| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Mike Rapoport | 9001 | 37.03% | 12 | 1.27% |
| Mel Gorman | 4008 | 16.49% | 135 | 14.33% |
| Johannes Weiner | 1214 | 4.99% | 25 | 2.65% |
| Huang Ying | 1006 | 4.14% | 9 | 0.96% |
| Kirill A. Shutemov | 670 | 2.76% | 13 | 1.38% |
| Vlastimil Babka | 444 | 1.83% | 47 | 4.99% |
| Alexander Duyck | 391 | 1.61% | 13 | 1.38% |
| Kamezawa Hiroyuki | 357 | 1.47% | 7 | 0.74% |
| Michal Nazarewicz | 351 | 1.44% | 7 | 0.74% |
| Michal Hocko | 340 | 1.40% | 34 | 3.61% |
| Matthew Wilcox | 328 | 1.35% | 20 | 2.12% |
| Andrew Morton | 317 | 1.30% | 39 | 4.14% |
| JoonSoo Kim | 307 | 1.26% | 27 | 2.87% |
| Oscar Salvador | 304 | 1.25% | 6 | 0.64% |
| Anshuman Khandual | 269 | 1.11% | 3 | 0.32% |
| Christoph Lameter | 242 | 1.00% | 28 | 2.97% |
| David Hildenbrand | 230 | 0.95% | 18 | 1.91% |
| Kefeng Wang | 223 | 0.92% | 9 | 0.96% |
| Fengguang Wu | 213 | 0.88% | 2 | 0.21% |
| Pavel Tatashin | 211 | 0.87% | 15 | 1.59% |
| MinChan Kim | 171 | 0.70% | 17 | 1.80% |
| Hugh Dickins | 155 | 0.64% | 10 | 1.06% |
| Linus Torvalds (pre-git) | 142 | 0.58% | 24 | 2.55% |
| Suren Baghdasaryan | 132 | 0.54% | 7 | 0.74% |
| Dave Hansen | 118 | 0.49% | 10 | 1.06% |
| Andrey Konovalov | 118 | 0.49% | 18 | 1.91% |
| Naoya Horiguchi | 112 | 0.46% | 4 | 0.42% |
| Zi Yan | 101 | 0.42% | 9 | 0.96% |
| Baoquan He | 100 | 0.41% | 5 | 0.53% |
| Dan J Williams | 98 | 0.40% | 6 | 0.64% |
| Richard Chang | 90 | 0.37% | 1 | 0.11% |
| Marek Szyprowski | 85 | 0.35% | 4 | 0.42% |
| Nicholas Piggin | 80 | 0.33% | 16 | 1.70% |
| Charan Teja Reddy | 78 | 0.32% | 7 | 0.74% |
| Andi Kleen | 78 | 0.32% | 8 | 0.85% |
| Jiang Liu | 77 | 0.32% | 8 | 0.85% |
| Christoph Hellwig | 67 | 0.28% | 2 | 0.21% |
| David Rientjes | 64 | 0.26% | 14 | 1.49% |
| Rohit Seth | 60 | 0.25% | 2 | 0.21% |
| Joao Martins | 55 | 0.23% | 1 | 0.11% |
| Miaohe Lin | 54 | 0.22% | 11 | 1.17% |
| Wei Yang | 54 | 0.22% | 11 | 1.17% |
| Linus Torvalds | 52 | 0.21% | 10 | 1.06% |
| David Howells | 51 | 0.21% | 3 | 0.32% |
| Cody P Schafer | 50 | 0.21% | 6 | 0.64% |
| Lin Yun Sheng | 48 | 0.20% | 3 | 0.32% |
| Alexander Potapenko | 47 | 0.19% | 3 | 0.32% |
| Eric Dumazet | 44 | 0.18% | 5 | 0.53% |
| Stanislaw Gruszka | 44 | 0.18% | 1 | 0.11% |
| Jesper Dangaard Brouer | 44 | 0.18% | 2 | 0.21% |
| Peter Zijlstra | 40 | 0.16% | 2 | 0.21% |
| Jaewon Kim | 40 | 0.16% | 2 | 0.21% |
| Lucas Stach | 39 | 0.16% | 4 | 0.42% |
| Akinobu Mita | 39 | 0.16% | 3 | 0.32% |
| Peter Collingbourne | 37 | 0.15% | 3 | 0.32% |
| Lee Schermerhorn | 36 | 0.15% | 3 | 0.32% |
| Daniel Jordan | 35 | 0.14% | 3 | 0.32% |
| Wen Congyang | 31 | 0.13% | 1 | 0.11% |
| Motohiro Kosaki | 30 | 0.12% | 6 | 0.64% |
| Art Haas | 29 | 0.12% | 1 | 0.11% |
| Arun K S | 27 | 0.11% | 3 | 0.32% |
| Sebastian Andrzej Siewior | 26 | 0.11% | 3 | 0.32% |
| Daniel Vetter | 26 | 0.11% | 1 | 0.11% |
| Aaron Lu | 26 | 0.11% | 4 | 0.42% |
| Waiman Long | 26 | 0.11% | 1 | 0.11% |
| Robin Holt | 25 | 0.10% | 1 | 0.11% |
| Li Zhijian | 24 | 0.10% | 1 | 0.11% |
| Qi Zheng | 23 | 0.09% | 3 | 0.32% |
| Andy Whitcroft | 22 | 0.09% | 3 | 0.32% |
| Matthew Dobson | 21 | 0.09% | 2 | 0.21% |
| Hyesoo Yu | 20 | 0.08% | 1 | 0.11% |
| Glauber de Oliveira Costa | 18 | 0.07% | 1 | 0.11% |
| Baolin Wang | 18 | 0.07% | 4 | 0.42% |
| Andrea Arcangeli | 17 | 0.07% | 4 | 0.42% |
| Timur Tabi | 17 | 0.07% | 1 | 0.11% |
| liuq | 16 | 0.07% | 1 | 0.11% |
| KeMeng Shi | 15 | 0.06% | 4 | 0.42% |
| Pavel Machek | 15 | 0.06% | 3 | 0.32% |
| Qian Cai | 15 | 0.06% | 2 | 0.21% |
| gehao | 15 | 0.06% | 3 | 0.32% |
| Brendan Jackman | 15 | 0.06% | 1 | 0.11% |
| Vladimir Davydov | 15 | 0.06% | 2 | 0.21% |
| Benjamin Poirier | 14 | 0.06% | 1 | 0.11% |
| Gilad Ben-Yossef | 14 | 0.06% | 1 | 0.11% |
| Feng Tang | 14 | 0.06% | 1 | 0.11% |
| Catalin Marinas | 14 | 0.06% | 2 | 0.21% |
| Laura Abbott | 13 | 0.05% | 4 | 0.42% |
| Hideo Aoki | 13 | 0.05% | 1 | 0.11% |
| Andrey Ryabinin | 13 | 0.05% | 3 | 0.32% |
| yangge | 13 | 0.05% | 1 | 0.11% |
| Xishi Qiu | 12 | 0.05% | 3 | 0.32% |
| Harvey Harrison | 12 | 0.05% | 1 | 0.11% |
| Liu Ping Fan | 11 | 0.05% | 1 | 0.11% |
| Nadia Yvette Chambers | 11 | 0.05% | 1 | 0.11% |
| Rusty Russell | 10 | 0.04% | 4 | 0.42% |
| Miklos Szeredi | 9 | 0.04% | 1 | 0.11% |
| Kemi Wang | 9 | 0.04% | 2 | 0.21% |
| Mike Kravetz | 9 | 0.04% | 2 | 0.21% |
| Roman Gushchin | 9 | 0.04% | 3 | 0.32% |
| Konstantin Khlebnikov | 9 | 0.04% | 1 | 0.11% |
| Srinivas Pandruvada | 9 | 0.04% | 1 | 0.11% |
| Rafael J. Wysocki | 9 | 0.04% | 3 | 0.32% |
| Aaron Tomlin | 8 | 0.03% | 1 | 0.11% |
| Sasha Levin | 8 | 0.03% | 2 | 0.21% |
| Luiz Fernando N. Capitulino | 8 | 0.03% | 1 | 0.11% |
| Jason Gunthorpe | 8 | 0.03% | 1 | 0.11% |
| Srikar Dronamraju | 8 | 0.03% | 1 | 0.11% |
| Uros Bizjak | 8 | 0.03% | 1 | 0.11% |
| Benjamin Herrenschmidt | 8 | 0.03% | 2 | 0.21% |
| Nathan Zimmer | 8 | 0.03% | 1 | 0.11% |
| Martin Hicks | 8 | 0.03% | 2 | 0.21% |
| Joel Granados | 7 | 0.03% | 1 | 0.11% |
| Bartlomiej Zolnierkiewicz | 7 | 0.03% | 2 | 0.21% |
| Song Muchun | 7 | 0.03% | 3 | 0.32% |
| Tetsuo Handa | 7 | 0.03% | 3 | 0.32% |
| Emese Revfy | 7 | 0.03% | 2 | 0.21% |
| Mateusz Nosek | 7 | 0.03% | 2 | 0.21% |
| Omar Sandoval | 7 | 0.03% | 1 | 0.11% |
| Chen Yu | 6 | 0.02% | 1 | 0.11% |
| Brent Casavant | 6 | 0.02% | 1 | 0.11% |
| Rik Van Riel | 6 | 0.02% | 2 | 0.21% |
| Keith Mannthey | 6 | 0.02% | 1 | 0.11% |
| Yu Zhao | 6 | 0.02% | 2 | 0.21% |
| Liangcai Fan | 6 | 0.02% | 1 | 0.11% |
| Alexandre Ghiti | 6 | 0.02% | 2 | 0.21% |
| seokhoon.yoon | 6 | 0.02% | 1 | 0.11% |
| Dean Nelson | 6 | 0.02% | 1 | 0.11% |
| Tony Luck | 6 | 0.02% | 2 | 0.21% |
| Ingo Molnar | 5 | 0.02% | 3 | 0.32% |
| Vegard Nossum | 5 | 0.02% | 1 | 0.11% |
| Vincenzo Frascino | 5 | 0.02% | 1 | 0.11% |
| Adam Litke | 5 | 0.02% | 1 | 0.11% |
| Keith Busch | 5 | 0.02% | 1 | 0.11% |
| David Chen | 5 | 0.02% | 1 | 0.11% |
| Jason (Hui) Wang | 5 | 0.02% | 1 | 0.11% |
| Nicolas Saenz Julienne | 5 | 0.02% | 2 | 0.21% |
| Randy Dunlap | 4 | 0.02% | 3 | 0.32% |
| Paul Jackson | 4 | 0.02% | 2 | 0.21% |
| Jose R. Santos | 4 | 0.02% | 1 | 0.11% |
| Yinghai Lu | 4 | 0.02% | 1 | 0.11% |
| Kevin Hao | 4 | 0.02% | 1 | 0.11% |
| Vijay Balakrishna | 4 | 0.02% | 1 | 0.11% |
| Kirill Korotaev | 4 | 0.02% | 1 | 0.11% |
| Weijie Yang | 4 | 0.02% | 1 | 0.11% |
| Yang Shi | 4 | 0.02% | 2 | 0.21% |
| Alexey Dobriyan | 4 | 0.02% | 3 | 0.32% |
| Chuck Lever | 4 | 0.02% | 1 | 0.11% |
| Geliang Tang | 4 | 0.02% | 2 | 0.21% |
| Yajun Deng | 4 | 0.02% | 2 | 0.21% |
| Ard Biesheuvel | 4 | 0.02% | 1 | 0.11% |
| Youquan Song | 3 | 0.01% | 1 | 0.11% |
| Han Pingtian | 3 | 0.01% | 1 | 0.11% |
| Doug Berger | 3 | 0.01% | 1 | 0.11% |
| Dave Jones | 3 | 0.01% | 1 | 0.11% |
| Vlad Yasevich | 3 | 0.01% | 1 | 0.11% |
| Liu hailong | 3 | 0.01% | 1 | 0.11% |
| Thorsten Blum | 3 | 0.01% | 1 | 0.11% |
| Yaowei Bai | 3 | 0.01% | 2 | 0.21% |
| Martin J. Bligh | 3 | 0.01% | 1 | 0.11% |
| Balbir Singh | 3 | 0.01% | 1 | 0.11% |
| Ben Hutchings | 3 | 0.01% | 1 | 0.11% |
| Wonhyuk Yang | 3 | 0.01% | 1 | 0.11% |
| Adrian Bunk | 3 | 0.01% | 1 | 0.11% |
| Sudeep Holla | 3 | 0.01% | 1 | 0.11% |
| Shailabh Nagar | 3 | 0.01% | 1 | 0.11% |
| Zhou Guanghui | 3 | 0.01% | 1 | 0.11% |
| Arnaldo Carvalho de Melo | 3 | 0.01% | 1 | 0.11% |
| Rasmus Villemoes | 2 | 0.01% | 2 | 0.21% |
| Dongli Zhang | 2 | 0.01% | 1 | 0.11% |
| Hideaki Yoshifuji / 吉藤英明 | 2 | 0.01% | 1 | 0.11% |
| Srivatsa S. Bhat | 2 | 0.01% | 1 | 0.11% |
| Lorenzo Stoakes | 2 | 0.01% | 1 | 0.11% |
| Lai Jiangshan | 2 | 0.01% | 1 | 0.11% |
| Kees Cook | 2 | 0.01% | 1 | 0.11% |
| Arnd Bergmann | 2 | 0.01% | 1 | 0.11% |
| Matteo Croce | 2 | 0.01% | 1 | 0.11% |
| Jan Beulich | 2 | 0.01% | 1 | 0.11% |
| Matthias Kaehlcke | 2 | 0.01% | 1 | 0.11% |
| nixiaoming | 2 | 0.01% | 1 | 0.11% |
| Steven Rostedt | 2 | 0.01% | 1 | 0.11% |
| haifeng.xu | 2 | 0.01% | 1 | 0.11% |
| Joe Perches | 2 | 0.01% | 1 | 0.11% |
| Maurizio Lombardi | 2 | 0.01% | 1 | 0.11% |
| Nishanth Aravamudan | 2 | 0.01% | 1 | 0.11% |
| Roman Zippel | 2 | 0.01% | 1 | 0.11% |
| chenqiwu | 1 | 0.00% | 1 | 0.11% |
| Greg Kroah-Hartman | 1 | 0.00% | 1 | 0.11% |
| Dimitri Sivanich | 1 | 0.00% | 1 | 0.11% |
| zhong jiang | 1 | 0.00% | 1 | 0.11% |
| Shile Zhang | 1 | 0.00% | 1 | 0.11% |
| Laurent Dufour | 1 | 0.00% | 1 | 0.11% |
| Francesco Fusco | 1 | 0.00% | 1 | 0.11% |
| Jason Yan | 1 | 0.00% | 1 | 0.11% |
| Yafang Shao | 1 | 0.00% | 1 | 0.11% |
| Paul Mundt | 1 | 0.00% | 1 | 0.11% |
| Ran Xiaokai | 1 | 0.00% | 1 | 0.11% |
| Jerry Zhou | 1 | 0.00% | 1 | 0.11% |
| Joel Savitz | 1 | 0.00% | 1 | 0.11% |
| Pintu Kumar | 1 | 0.00% | 1 | 0.11% |
| Tom Rix | 1 | 0.00% | 1 | 0.11% |
| Maninder Singh | 1 | 0.00% | 1 | 0.11% |
| Helge Deller | 1 | 0.00% | 1 | 0.11% |
| Li Zhe | 1 | 0.00% | 1 | 0.11% |
| Henry Willard | 1 | 0.00% | 1 | 0.11% |
| Rafael Aquini | 1 | 0.00% | 1 | 0.11% |
| Thomas Gleixner | 1 | 0.00% | 1 | 0.11% |
| Total | 24305 | 942 |
// SPDX-License-Identifier: GPL-2.0-only /* * linux/mm/page_alloc.c * * Manages the free list, the system allocates free pages here. * Note that kmalloc() lives in slab.c * * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds * Swap reorganised 29.12.95, Stephen Tweedie * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 * Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999 * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999 * Zone balancing, Kanoj Sarcar, SGI, Jan 2000 * Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002 * (lots of bits borrowed from Ingo Molnar & Andrew Morton) */ #include <linux/stddef.h> #include <linux/mm.h> #include <linux/highmem.h> #include <linux/interrupt.h> #include <linux/jiffies.h> #include <linux/compiler.h> #include <linux/kernel.h> #include <linux/kasan.h> #include <linux/kmsan.h> #include <linux/module.h> #include <linux/suspend.h> #include <linux/ratelimit.h> #include <linux/oom.h> #include <linux/topology.h> #include <linux/sysctl.h> #include <linux/cpu.h> #include <linux/cpuset.h> #include <linux/pagevec.h> #include <linux/memory_hotplug.h> #include <linux/nodemask.h> #include <linux/vmstat.h> #include <linux/fault-inject.h> #include <linux/compaction.h> #include <trace/events/kmem.h> #include <trace/events/oom.h> #include <linux/prefetch.h> #include <linux/mm_inline.h> #include <linux/mmu_notifier.h> #include <linux/migrate.h> #include <linux/sched/mm.h> #include <linux/page_owner.h> #include <linux/page_table_check.h> #include <linux/memcontrol.h> #include <linux/ftrace.h> #include <linux/lockdep.h> #include <linux/psi.h> #include <linux/khugepaged.h> #include <linux/delayacct.h> #include <linux/cacheinfo.h> #include <linux/pgalloc_tag.h> #include <asm/div64.h> #include "internal.h" #include "shuffle.h" #include "page_reporting.h" /* Free Page Internal flags: for internal, non-pcp variants of free_pages(). */ typedef int __bitwise fpi_t; /* No special request */ #define FPI_NONE ((__force fpi_t)0) /* * Skip free page reporting notification for the (possibly merged) page. * This does not hinder free page reporting from grabbing the page, * reporting it and marking it "reported" - it only skips notifying * the free page reporting infrastructure about a newly freed page. For * example, used when temporarily pulling a page from a freelist and * putting it back unmodified. */ #define FPI_SKIP_REPORT_NOTIFY ((__force fpi_t)BIT(0)) /* * Place the (possibly merged) page to the tail of the freelist. Will ignore * page shuffling (relevant code - e.g., memory onlining - is expected to * shuffle the whole zone). * * Note: No code should rely on this flag for correctness - it's purely * to allow for optimizations when handing back either fresh pages * (memory onlining) or untouched pages (page isolation, free page * reporting). */ #define FPI_TO_TAIL ((__force fpi_t)BIT(1)) /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */ static DEFINE_MUTEX(pcp_batch_high_lock); #define MIN_PERCPU_PAGELIST_HIGH_FRACTION (8) #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT) /* * On SMP, spin_trylock is sufficient protection. * On PREEMPT_RT, spin_trylock is equivalent on both SMP and UP. */ #define pcp_trylock_prepare(flags) do { } while (0) #define pcp_trylock_finish(flag) do { } while (0) #else /* UP spin_trylock always succeeds so disable IRQs to prevent re-entrancy. */ #define pcp_trylock_prepare(flags) local_irq_save(flags) #define pcp_trylock_finish(flags) local_irq_restore(flags) #endif /* * Locking a pcp requires a PCP lookup followed by a spinlock. To avoid * a migration causing the wrong PCP to be locked and remote memory being * potentially allocated, pin the task to the CPU for the lookup+lock. * preempt_disable is used on !RT because it is faster than migrate_disable. * migrate_disable is used on RT because otherwise RT spinlock usage is * interfered with and a high priority task cannot preempt the allocator. */ #ifndef CONFIG_PREEMPT_RT #define pcpu_task_pin() preempt_disable() #define pcpu_task_unpin() preempt_enable() #else #define pcpu_task_pin() migrate_disable() #define pcpu_task_unpin() migrate_enable() #endif /* * Generic helper to lookup and a per-cpu variable with an embedded spinlock. * Return value should be used with equivalent unlock helper. */ #define pcpu_spin_lock(type, member, ptr) \ ({ \ type *_ret; \ pcpu_task_pin(); \ _ret = this_cpu_ptr(ptr); \ spin_lock(&_ret->member); \ _ret; \ }) #define pcpu_spin_trylock(type, member, ptr) \ ({ \ type *_ret; \ pcpu_task_pin(); \ _ret = this_cpu_ptr(ptr); \ if (!spin_trylock(&_ret->member)) { \ pcpu_task_unpin(); \ _ret = NULL; \ } \ _ret; \ }) #define pcpu_spin_unlock(member, ptr) \ ({ \ spin_unlock(&ptr->member); \ pcpu_task_unpin(); \ }) /* struct per_cpu_pages specific helpers. */ #define pcp_spin_lock(ptr) \ pcpu_spin_lock(struct per_cpu_pages, lock, ptr) #define pcp_spin_trylock(ptr) \ pcpu_spin_trylock(struct per_cpu_pages, lock, ptr) #define pcp_spin_unlock(ptr) \ pcpu_spin_unlock(lock, ptr) #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID DEFINE_PER_CPU(int, numa_node); EXPORT_PER_CPU_SYMBOL(numa_node); #endif DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key); #ifdef CONFIG_HAVE_MEMORYLESS_NODES /* * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly. * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined. * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem() * defined in <linux/topology.h>. */ DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */ EXPORT_PER_CPU_SYMBOL(_numa_mem_); #endif static DEFINE_MUTEX(pcpu_drain_mutex); #ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY volatile unsigned long latent_entropy __latent_entropy; EXPORT_SYMBOL(latent_entropy); #endif /* * Array of node states. */ nodemask_t node_states[NR_NODE_STATES] __read_mostly = { [N_POSSIBLE] = NODE_MASK_ALL, [N_ONLINE] = { { [0] = 1UL } }, #ifndef CONFIG_NUMA [N_NORMAL_MEMORY] = { { [0] = 1UL } }, #ifdef CONFIG_HIGHMEM [N_HIGH_MEMORY] = { { [0] = 1UL } }, #endif [N_MEMORY] = { { [0] = 1UL } }, [N_CPU] = { { [0] = 1UL } }, #endif /* NUMA */ }; EXPORT_SYMBOL(node_states); gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK; #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE unsigned int pageblock_order __read_mostly; #endif static void __free_pages_ok(struct page *page, unsigned int order, fpi_t fpi_flags); /* * results with 256, 32 in the lowmem_reserve sysctl: * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high) * 1G machine -> (16M dma, 784M normal, 224M high) * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL * HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA * * TBD: should special case ZONE_DMA32 machines here - in those we normally * don't need any ZONE_NORMAL reservation */ static int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = { #ifdef CONFIG_ZONE_DMA [ZONE_DMA] = 256, #endif #ifdef CONFIG_ZONE_DMA32 [ZONE_DMA32] = 256, #endif [ZONE_NORMAL] = 32, #ifdef CONFIG_HIGHMEM [ZONE_HIGHMEM] = 0, #endif [ZONE_MOVABLE] = 0, }; char * const zone_names[MAX_NR_ZONES] = { #ifdef CONFIG_ZONE_DMA "DMA", #endif #ifdef CONFIG_ZONE_DMA32 "DMA32", #endif "Normal", #ifdef CONFIG_HIGHMEM "HighMem", #endif "Movable", #ifdef CONFIG_ZONE_DEVICE "Device", #endif }; const char * const migratetype_names[MIGRATE_TYPES] = { "Unmovable", "Movable", "Reclaimable", "HighAtomic", #ifdef CONFIG_CMA "CMA", #endif #ifdef CONFIG_MEMORY_ISOLATION "Isolate", #endif }; int min_free_kbytes = 1024; int user_min_free_kbytes = -1; static int watermark_boost_factor __read_mostly = 15000; static int watermark_scale_factor = 10; /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */ int movable_zone; EXPORT_SYMBOL(movable_zone); #if MAX_NUMNODES > 1 unsigned int nr_node_ids __read_mostly = MAX_NUMNODES; unsigned int nr_online_nodes __read_mostly = 1; EXPORT_SYMBOL(nr_node_ids); EXPORT_SYMBOL(nr_online_nodes); #endif static bool page_contains_unaccepted(struct page *page, unsigned int order); static void accept_page(struct page *page, unsigned int order); static bool cond_accept_memory(struct zone *zone, unsigned int order); static inline bool has_unaccepted_memory(void); static bool __free_unaccepted(struct page *page); int page_group_by_mobility_disabled __read_mostly; #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT /* * During boot we initialize deferred pages on-demand, as needed, but once * page_alloc_init_late() has finished, the deferred pages are all initialized, * and we can permanently disable that path. */ DEFINE_STATIC_KEY_TRUE(deferred_pages); static inline bool deferred_pages_enabled(void) { return static_branch_unlikely(&deferred_pages); } /* * deferred_grow_zone() is __init, but it is called from * get_page_from_freelist() during early boot until deferred_pages permanently * disables this call. This is why we have refdata wrapper to avoid warning, * and to ensure that the function body gets unloaded. */ static bool __ref _deferred_grow_zone(struct zone *zone, unsigned int order) { return deferred_grow_zone(zone, order); } #else static inline bool deferred_pages_enabled(void) { return false; } #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ /* Return a pointer to the bitmap storing bits affecting a block of pages */ static inline unsigned long *get_pageblock_bitmap(const struct page *page, unsigned long pfn) { #ifdef CONFIG_SPARSEMEM return section_to_usemap(__pfn_to_section(pfn)); #else return page_zone(page)->pageblock_flags; #endif /* CONFIG_SPARSEMEM */ } static inline int pfn_to_bitidx(const struct page *page, unsigned long pfn) { #ifdef CONFIG_SPARSEMEM pfn &= (PAGES_PER_SECTION-1); #else pfn = pfn - pageblock_start_pfn(page_zone(page)->zone_start_pfn); #endif /* CONFIG_SPARSEMEM */ return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS; } /** * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages * @page: The page within the block of interest * @pfn: The target page frame number * @mask: mask of bits that the caller is interested in * * Return: pageblock_bits flags */ unsigned long get_pfnblock_flags_mask(const struct page *page, unsigned long pfn, unsigned long mask) { unsigned long *bitmap; unsigned long bitidx, word_bitidx; unsigned long word; bitmap = get_pageblock_bitmap(page, pfn); bitidx = pfn_to_bitidx(page, pfn); word_bitidx = bitidx / BITS_PER_LONG; bitidx &= (BITS_PER_LONG-1); /* * This races, without locks, with set_pfnblock_flags_mask(). Ensure * a consistent read of the memory array, so that results, even though * racy, are not corrupted. */ word = READ_ONCE(bitmap[word_bitidx]); return (word >> bitidx) & mask; } static __always_inline int get_pfnblock_migratetype(const struct page *page, unsigned long pfn) { return get_pfnblock_flags_mask(page, pfn, MIGRATETYPE_MASK); } /** * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages * @page: The page within the block of interest * @flags: The flags to set * @pfn: The target page frame number * @mask: mask of bits that the caller is interested in */ void set_pfnblock_flags_mask(struct page *page, unsigned long flags, unsigned long pfn, unsigned long mask) { unsigned long *bitmap; unsigned long bitidx, word_bitidx; unsigned long word; BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4); BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits)); bitmap = get_pageblock_bitmap(page, pfn); bitidx = pfn_to_bitidx(page, pfn); word_bitidx = bitidx / BITS_PER_LONG; bitidx &= (BITS_PER_LONG-1); VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page); mask <<= bitidx; flags <<= bitidx; word = READ_ONCE(bitmap[word_bitidx]); do { } while (!try_cmpxchg(&bitmap[word_bitidx], &word, (word & ~mask) | flags)); } void set_pageblock_migratetype(struct page *page, int migratetype) { if (unlikely(page_group_by_mobility_disabled && migratetype < MIGRATE_PCPTYPES)) migratetype = MIGRATE_UNMOVABLE; set_pfnblock_flags_mask(page, (unsigned long)migratetype, page_to_pfn(page), MIGRATETYPE_MASK); } #ifdef CONFIG_DEBUG_VM static int page_outside_zone_boundaries(struct zone *zone, struct page *page) { int ret; unsigned seq; unsigned long pfn = page_to_pfn(page); unsigned long sp, start_pfn; do { seq = zone_span_seqbegin(zone); start_pfn = zone->zone_start_pfn; sp = zone->spanned_pages; ret = !zone_spans_pfn(zone, pfn); } while (zone_span_seqretry(zone, seq)); if (ret) pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n", pfn, zone_to_nid(zone), zone->name, start_pfn, start_pfn + sp); return ret; } /* * Temporary debugging check for pages not lying within a given zone. */ static bool __maybe_unused bad_range(struct zone *zone, struct page *page) { if (page_outside_zone_boundaries(zone, page)) return true; if (zone != page_zone(page)) return true; return false; } #else static inline bool __maybe_unused bad_range(struct zone *zone, struct page *page) { return false; } #endif static void bad_page(struct page *page, const char *reason) { static unsigned long resume; static unsigned long nr_shown; static unsigned long nr_unshown; /* * Allow a burst of 60 reports, then keep quiet for that minute; * or allow a steady drip of one report per second. */ if (nr_shown == 60) { if (time_before(jiffies, resume)) { nr_unshown++; goto out; } if (nr_unshown) { pr_alert( "BUG: Bad page state: %lu messages suppressed\n", nr_unshown); nr_unshown = 0; } nr_shown = 0; } if (nr_shown++ == 0) resume = jiffies + 60 * HZ; pr_alert("BUG: Bad page state in process %s pfn:%05lx\n", current->comm, page_to_pfn(page)); dump_page(page, reason); print_modules(); dump_stack(); out: /* Leave bad fields for debug, except PageBuddy could make trouble */ if (PageBuddy(page)) __ClearPageBuddy(page); add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); } static inline unsigned int order_to_pindex(int migratetype, int order) { bool __maybe_unused movable; #ifdef CONFIG_TRANSPARENT_HUGEPAGE if (order > PAGE_ALLOC_COSTLY_ORDER) { VM_BUG_ON(order != HPAGE_PMD_ORDER); movable = migratetype == MIGRATE_MOVABLE; return NR_LOWORDER_PCP_LISTS + movable; } #else VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER); #endif return (MIGRATE_PCPTYPES * order) + migratetype; } static inline int pindex_to_order(unsigned int pindex) { int order = pindex / MIGRATE_PCPTYPES; #ifdef CONFIG_TRANSPARENT_HUGEPAGE if (pindex >= NR_LOWORDER_PCP_LISTS) order = HPAGE_PMD_ORDER; #else VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER); #endif return order; } static inline bool pcp_allowed_order(unsigned int order) { if (order <= PAGE_ALLOC_COSTLY_ORDER) return true; #ifdef CONFIG_TRANSPARENT_HUGEPAGE if (order == HPAGE_PMD_ORDER) return true; #endif return false; } /* * Higher-order pages are called "compound pages". They are structured thusly: * * The first PAGE_SIZE page is called the "head page" and have PG_head set. * * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded * in bit 0 of page->compound_head. The rest of bits is pointer to head page. * * The first tail page's ->compound_order holds the order of allocation. * This usage means that zero-order pages may not be compound. */ void prep_compound_page(struct page *page, unsigned int order) { int i; int nr_pages = 1 << order; __SetPageHead(page); for (i = 1; i < nr_pages; i++) prep_compound_tail(page, i); prep_compound_head(page, order); } static inline void set_buddy_order(struct page *page, unsigned int order) { set_page_private(page, order); __SetPageBuddy(page); } #ifdef CONFIG_COMPACTION static inline struct capture_control *task_capc(struct zone *zone) { struct capture_control *capc = current->capture_control; return unlikely(capc) && !(current->flags & PF_KTHREAD) && !capc->page && capc->cc->zone == zone ? capc : NULL; } static inline bool compaction_capture(struct capture_control *capc, struct page *page, int order, int migratetype) { if (!capc || order != capc->cc->order) return false; /* Do not accidentally pollute CMA or isolated regions*/ if (is_migrate_cma(migratetype) || is_migrate_isolate(migratetype)) return false; /* * Do not let lower order allocations pollute a movable pageblock * unless compaction is also requesting movable pages. * This might let an unmovable request use a reclaimable pageblock * and vice-versa but no more than normal fallback logic which can * have trouble finding a high-order free page. */ if (order < pageblock_order && migratetype == MIGRATE_MOVABLE && capc->cc->migratetype != MIGRATE_MOVABLE) return false; capc->page = page; return true; } #else static inline struct capture_control *task_capc(struct zone *zone) { return NULL; } static inline bool compaction_capture(struct capture_control *capc, struct page *page, int order, int migratetype) { return false; } #endif /* CONFIG_COMPACTION */ static inline void account_freepages(struct zone *zone, int nr_pages, int migratetype) { if (is_migrate_isolate(migratetype)) return; __mod_zone_page_state(zone, NR_FREE_PAGES, nr_pages); if (is_migrate_cma(migratetype)) __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, nr_pages); } /* Used for pages not on another list */ static inline void __add_to_free_list(struct page *page, struct zone *zone, unsigned int order, int migratetype, bool tail) { struct free_area *area = &zone->free_area[order]; VM_WARN_ONCE(get_pageblock_migratetype(page) != migratetype, "page type is %lu, passed migratetype is %d (nr=%d)\n", get_pageblock_migratetype(page), migratetype, 1 << order); if (tail) list_add_tail(&page->buddy_list, &area->free_list[migratetype]); else list_add(&page->buddy_list, &area->free_list[migratetype]); area->nr_free++; } /* * Used for pages which are on another list. Move the pages to the tail * of the list - so the moved pages won't immediately be considered for * allocation again (e.g., optimization for memory onlining). */ static inline void move_to_free_list(struct page *page, struct zone *zone, unsigned int order, int old_mt, int new_mt) { struct free_area *area = &zone->free_area[order]; /* Free page moving can fail, so it happens before the type update */ VM_WARN_ONCE(get_pageblock_migratetype(page) != old_mt, "page type is %lu, passed migratetype is %d (nr=%d)\n", get_pageblock_migratetype(page), old_mt, 1 << order); list_move_tail(&page->buddy_list, &area->free_list[new_mt]); account_freepages(zone, -(1 << order), old_mt); account_freepages(zone, 1 << order, new_mt); } static inline void __del_page_from_free_list(struct page *page, struct zone *zone, unsigned int order, int migratetype) { VM_WARN_ONCE(get_pageblock_migratetype(page) != migratetype, "page type is %lu, passed migratetype is %d (nr=%d)\n", get_pageblock_migratetype(page), migratetype, 1 << order); /* clear reported state and update reported page count */ if (page_reported(page)) __ClearPageReported(page); list_del(&page->buddy_list); __ClearPageBuddy(page); set_page_private(page, 0); zone->free_area[order].nr_free--; } static inline void del_page_from_free_list(struct page *page, struct zone *zone, unsigned int order, int migratetype) { __del_page_from_free_list(page, zone, order, migratetype); account_freepages(zone, -(1 << order), migratetype); } static inline struct page *get_page_from_free_area(struct free_area *area, int migratetype) { return list_first_entry_or_null(&area->free_list[migratetype], struct page, buddy_list); } /* * If this is less than the 2nd largest possible page, check if the buddy * of the next-higher order is free. If it is, it's possible * that pages are being freed that will coalesce soon. In case, * that is happening, add the free page to the tail of the list * so it's less likely to be used soon and more likely to be merged * as a 2-level higher order page */ static inline bool buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn, struct page *page, unsigned int order) { unsigned long higher_page_pfn; struct page *higher_page; if (order >= MAX_PAGE_ORDER - 1) return false; higher_page_pfn = buddy_pfn & pfn; higher_page = page + (higher_page_pfn - pfn); return find_buddy_page_pfn(higher_page, higher_page_pfn, order + 1, NULL) != NULL; } /* * Freeing function for a buddy system allocator. * * The concept of a buddy system is to maintain direct-mapped table * (containing bit values) for memory blocks of various "orders". * The bottom level table contains the map for the smallest allocatable * units of memory (here, pages), and each level above it describes * pairs of units from the levels below, hence, "buddies". * At a high level, all that happens here is marking the table entry * at the bottom level available, and propagating the changes upward * as necessary, plus some accounting needed to play nicely with other * parts of the VM system. * At each level, we keep a list of pages, which are heads of continuous * free pages of length of (1 << order) and marked with PageBuddy. * Page's order is recorded in page_private(page) field. * So when we are allocating or freeing one, we can derive the state of the * other. That is, if we allocate a small block, and both were * free, the remainder of the region must be split into blocks. * If a block is freed, and its buddy is also free, then this * triggers coalescing into a block of larger size. * * -- nyc */ static inline void __free_one_page(struct page *page, unsigned long pfn, struct zone *zone, unsigned int order, int migratetype, fpi_t fpi_flags) { struct capture_control *capc = task_capc(zone); unsigned long buddy_pfn = 0; unsigned long combined_pfn; struct page *buddy; bool to_tail; VM_BUG_ON(!zone_is_initialized(zone)); VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page); VM_BUG_ON(migratetype == -1); VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page); VM_BUG_ON_PAGE(bad_range(zone, page), page); account_freepages(zone, 1 << order, migratetype); while (order < MAX_PAGE_ORDER) { int buddy_mt = migratetype; if (compaction_capture(capc, page, order, migratetype)) { account_freepages(zone, -(1 << order), migratetype); return; } buddy = find_buddy_page_pfn(page, pfn, order, &buddy_pfn); if (!buddy) goto done_merging; if (unlikely(order >= pageblock_order)) { /* * We want to prevent merge between freepages on pageblock * without fallbacks and normal pageblock. Without this, * pageblock isolation could cause incorrect freepage or CMA * accounting or HIGHATOMIC accounting. */ buddy_mt = get_pfnblock_migratetype(buddy, buddy_pfn); if (migratetype != buddy_mt && (!migratetype_is_mergeable(migratetype) || !migratetype_is_mergeable(buddy_mt))) goto done_merging; } /* * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page, * merge with it and move up one order. */ if (page_is_guard(buddy)) clear_page_guard(zone, buddy, order); else __del_page_from_free_list(buddy, zone, order, buddy_mt); if (unlikely(buddy_mt != migratetype)) { /* * Match buddy type. This ensures that an * expand() down the line puts the sub-blocks * on the right freelists. */ set_pageblock_migratetype(buddy, migratetype); } combined_pfn = buddy_pfn & pfn; page = page + (combined_pfn - pfn); pfn = combined_pfn; order++; } done_merging: set_buddy_order(page, order); if (fpi_flags & FPI_TO_TAIL) to_tail = true; else if (is_shuffle_order(order)) to_tail = shuffle_pick_tail(); else to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order); __add_to_free_list(page, zone, order, migratetype, to_tail); /* Notify page reporting subsystem of freed page */ if (!(fpi_flags & FPI_SKIP_REPORT_NOTIFY)) page_reporting_notify_free(order); } /* * A bad page could be due to a number of fields. Instead of multiple branches, * try and check multiple fields with one check. The caller must do a detailed * check if necessary. */ static inline bool page_expected_state(struct page *page, unsigned long check_flags) { if (unlikely(atomic_read(&page->_mapcount) != -1)) return false; if (unlikely((unsigned long)page->mapping | page_ref_count(page) | #ifdef CONFIG_MEMCG page->memcg_data | #endif #ifdef CONFIG_PAGE_POOL ((page->pp_magic & ~0x3UL) == PP_SIGNATURE) | #endif (page->flags & check_flags))) return false; return true; } static const char *page_bad_reason(struct page *page, unsigned long flags) { const char *bad_reason = NULL; if (unlikely(atomic_read(&page->_mapcount) != -1)) bad_reason = "nonzero mapcount"; if (unlikely(page->mapping != NULL)) bad_reason = "non-NULL mapping"; if (unlikely(page_ref_count(page) != 0)) bad_reason = "nonzero _refcount"; if (unlikely(page->flags & flags)) { if (flags == PAGE_FLAGS_CHECK_AT_PREP) bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag(s) set"; else bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set"; } #ifdef CONFIG_MEMCG if (unlikely(page->memcg_data)) bad_reason = "page still charged to cgroup"; #endif #ifdef CONFIG_PAGE_POOL if (unlikely((page->pp_magic & ~0x3UL) == PP_SIGNATURE)) bad_reason = "page_pool leak"; #endif return bad_reason; } static void free_page_is_bad_report(struct page *page) { bad_page(page, page_bad_reason(page, PAGE_FLAGS_CHECK_AT_FREE)); } static inline bool free_page_is_bad(struct page *page) { if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE))) return false; /* Something has gone sideways, find it */ free_page_is_bad_report(page); return true; } static inline bool is_check_pages_enabled(void) { return static_branch_unlikely(&check_pages_enabled); } static int free_tail_page_prepare(struct page *head_page, struct page *page) { struct folio *folio = (struct folio *)head_page; int ret = 1; /* * We rely page->lru.next never has bit 0 set, unless the page * is PageTail(). Let's make sure that's true even for poisoned ->lru. */ BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1); if (!is_check_pages_enabled()) { ret = 0; goto out; } switch (page - head_page) { case 1: /* the first tail page: these may be in place of ->mapping */ if (unlikely(folio_entire_mapcount(folio))) { bad_page(page, "nonzero entire_mapcount"); goto out; } if (unlikely(folio_large_mapcount(folio))) { bad_page(page, "nonzero large_mapcount"); goto out; } if (unlikely(atomic_read(&folio->_nr_pages_mapped))) { bad_page(page, "nonzero nr_pages_mapped"); goto out; } if (unlikely(atomic_read(&folio->_pincount))) { bad_page(page, "nonzero pincount"); goto out; } break; case 2: /* the second tail page: deferred_list overlaps ->mapping */ if (unlikely(!list_empty(&folio->_deferred_list))) { bad_page(page, "on deferred list"); goto out; } break; default: if (page->mapping != TAIL_MAPPING) { bad_page(page, "corrupted mapping in tail page"); goto out; } break; } if (unlikely(!PageTail(page))) { bad_page(page, "PageTail not set"); goto out; } if (unlikely(compound_head(page) != head_page)) { bad_page(page, "compound_head not consistent"); goto out; } ret = 0; out: page->mapping = NULL; clear_compound_head(page); return ret; } /* * Skip KASAN memory poisoning when either: * * 1. For generic KASAN: deferred memory initialization has not yet completed. * Tag-based KASAN modes skip pages freed via deferred memory initialization * using page tags instead (see below). * 2. For tag-based KASAN modes: the page has a match-all KASAN tag, indicating * that error detection is disabled for accesses via the page address. * * Pages will have match-all tags in the following circumstances: * * 1. Pages are being initialized for the first time, including during deferred * memory init; see the call to page_kasan_tag_reset in __init_single_page. * 2. The allocation was not unpoisoned due to __GFP_SKIP_KASAN, with the * exception of pages unpoisoned by kasan_unpoison_vmalloc. * 3. The allocation was excluded from being checked due to sampling, * see the call to kasan_unpoison_pages. * * Poisoning pages during deferred memory init will greatly lengthen the * process and cause problem in large memory systems as the deferred pages * initialization is done with interrupt disabled. * * Assuming that there will be no reference to those newly initialized * pages before they are ever allocated, this should have no effect on * KASAN memory tracking as the poison will be properly inserted at page * allocation time. The only corner case is when pages are allocated by * on-demand allocation and then freed again before the deferred pages * initialization is done, but this is not likely to happen. */ static inline bool should_skip_kasan_poison(struct page *page) { if (IS_ENABLED(CONFIG_KASAN_GENERIC)) return deferred_pages_enabled(); return page_kasan_tag(page) == KASAN_TAG_KERNEL; } static void kernel_init_pages(struct page *page, int numpages) { int i; /* s390's use of memset() could override KASAN redzones. */ kasan_disable_current(); for (i = 0; i < numpages; i++) clear_highpage_kasan_tagged(page + i); kasan_enable_current(); } __always_inline bool free_pages_prepare(struct page *page, unsigned int order) { int bad = 0; bool skip_kasan_poison = should_skip_kasan_poison(page); bool init = want_init_on_free(); bool compound = PageCompound(page); VM_BUG_ON_PAGE(PageTail(page), page); trace_mm_page_free(page, order); kmsan_free_page(page, order); if (memcg_kmem_online() && PageMemcgKmem(page)) __memcg_kmem_uncharge_page(page, order); if (unlikely(PageHWPoison(page)) && !order) { /* Do not let hwpoison pages hit pcplists/buddy */ reset_page_owner(page, order); page_table_check_free(page, order); pgalloc_tag_sub(page, 1 << order); /* * The page is isolated and accounted for. * Mark the codetag as empty to avoid accounting error * when the page is freed by unpoison_memory(). */ clear_page_tag_ref(page); return false; } VM_BUG_ON_PAGE(compound && compound_order(page) != order, page); /* * Check tail pages before head page information is cleared to * avoid checking PageCompound for order-0 pages. */ if (unlikely(order)) { int i; if (compound) page[1].flags &= ~PAGE_FLAGS_SECOND; for (i = 1; i < (1 << order); i++) { if (compound) bad += free_tail_page_prepare(page, page + i); if (is_check_pages_enabled()) { if (free_page_is_bad(page + i)) { bad++; continue; } } (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; } } if (PageMappingFlags(page)) page->mapping = NULL; if (is_check_pages_enabled()) { if (free_page_is_bad(page)) bad++; if (bad) return false; } page_cpupid_reset_last(page); page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; reset_page_owner(page, order); page_table_check_free(page, order); pgalloc_tag_sub(page, 1 << order); if (!PageHighMem(page)) { debug_check_no_locks_freed(page_address(page), PAGE_SIZE << order); debug_check_no_obj_freed(page_address(page), PAGE_SIZE << order); } kernel_poison_pages(page, 1 << order); /* * As memory initialization might be integrated into KASAN, * KASAN poisoning and memory initialization code must be * kept together to avoid discrepancies in behavior. * * With hardware tag-based KASAN, memory tags must be set before the * page becomes unavailable via debug_pagealloc or arch_free_page. */ if (!skip_kasan_poison) { kasan_poison_pages(page, order, init); /* Memory is already initialized if KASAN did it internally. */ if (kasan_has_integrated_init()) init = false; } if (init) kernel_init_pages(page, 1 << order); /* * arch_free_page() can make the page's contents inaccessible. s390 * does this. So nothing which can access the page's contents should * happen after this. */ arch_free_page(page, order); debug_pagealloc_unmap_pages(page, 1 << order); return true; } /* * Frees a number of pages from the PCP lists * Assumes all pages on list are in same zone. * count is the number of pages to free. */ static void free_pcppages_bulk(struct zone *zone, int count, struct per_cpu_pages *pcp, int pindex) { unsigned long flags; unsigned int order; struct page *page; /* * Ensure proper count is passed which otherwise would stuck in the * below while (list_empty(list)) loop. */ count = min(pcp->count, count); /* Ensure requested pindex is drained first. */ pindex = pindex - 1; spin_lock_irqsave(&zone->lock, flags); while (count > 0) { struct list_head *list; int nr_pages; /* Remove pages from lists in a round-robin fashion. */ do { if (++pindex > NR_PCP_LISTS - 1) pindex = 0; list = &pcp->lists[pindex]; } while (list_empty(list)); order = pindex_to_order(pindex); nr_pages = 1 << order; do { unsigned long pfn; int mt; page = list_last_entry(list, struct page, pcp_list); pfn = page_to_pfn(page); mt = get_pfnblock_migratetype(page, pfn); /* must delete to avoid corrupting pcp list */ list_del(&page->pcp_list); count -= nr_pages; pcp->count -= nr_pages; __free_one_page(page, pfn, zone, order, mt, FPI_NONE); trace_mm_page_pcpu_drain(page, order, mt); } while (count > 0 && !list_empty(list)); } spin_unlock_irqrestore(&zone->lock, flags); } static void free_one_page(struct zone *zone, struct page *page, unsigned long pfn, unsigned int order, fpi_t fpi_flags) { unsigned long flags; int migratetype; spin_lock_irqsave(&zone->lock, flags); migratetype = get_pfnblock_migratetype(page, pfn); __free_one_page(page, pfn, zone, order, migratetype, fpi_flags); spin_unlock_irqrestore(&zone->lock, flags); } static void __free_pages_ok(struct page *page, unsigned int order, fpi_t fpi_flags) { unsigned long pfn = page_to_pfn(page); struct zone *zone = page_zone(page); if (!free_pages_prepare(page, order)) return; free_one_page(zone, page, pfn, order, fpi_flags); __count_vm_events(PGFREE, 1 << order); } void __meminit __free_pages_core(struct page *page, unsigned int order, enum meminit_context context) { unsigned int nr_pages = 1 << order; struct page *p = page; unsigned int loop; /* * When initializing the memmap, __init_single_page() sets the refcount * of all pages to 1 ("allocated"/"not free"). We have to set the * refcount of all involved pages to 0. * * Note that hotplugged memory pages are initialized to PageOffline(). * Pages freed from memblock might be marked as reserved. */ if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG) && unlikely(context == MEMINIT_HOTPLUG)) { for (loop = 0; loop < nr_pages; loop++, p++) { VM_WARN_ON_ONCE(PageReserved(p)); __ClearPageOffline(p); set_page_count(p, 0); } /* * Freeing the page with debug_pagealloc enabled will try to * unmap it; some archs don't like double-unmappings, so * map it first. */ debug_pagealloc_map_pages(page, nr_pages); adjust_managed_page_count(page, nr_pages); } else { for (loop = 0; loop < nr_pages; loop++, p++) { __ClearPageReserved(p); set_page_count(p, 0); } /* memblock adjusts totalram_pages() manually. */ atomic_long_add(nr_pages, &page_zone(page)->managed_pages); } if (page_contains_unaccepted(page, order)) { if (order == MAX_PAGE_ORDER && __free_unaccepted(page)) return; accept_page(page, order); } /* * Bypass PCP and place fresh pages right to the tail, primarily * relevant for memory onlining. */ __free_pages_ok(page, order, FPI_TO_TAIL); } /* * Check that the whole (or subset of) a pageblock given by the interval of * [start_pfn, end_pfn) is valid and within the same zone, before scanning it * with the migration of free compaction scanner. * * Return struct page pointer of start_pfn, or NULL if checks were not passed. * * It's possible on some configurations to have a setup like node0 node1 node0 * i.e. it's possible that all pages within a zones range of pages do not * belong to a single zone. We assume that a border between node0 and node1 * can occur within a single pageblock, but not a node0 node1 node0 * interleaving within a single pageblock. It is therefore sufficient to check * the first and last page of a pageblock and avoid checking each individual * page in a pageblock. * * Note: the function may return non-NULL struct page even for a page block * which contains a memory hole (i.e. there is no physical memory for a subset * of the pfn range). For example, if the pageblock order is MAX_PAGE_ORDER, which * will fall into 2 sub-sections, and the end pfn of the pageblock may be hole * even though the start pfn is online and valid. This should be safe most of * the time because struct pages are still initialized via init_unavailable_range() * and pfn walkers shouldn't touch any physical memory range for which they do * not recognize any specific metadata in struct pages. */ struct page *__pageblock_pfn_to_page(unsigned long start_pfn, unsigned long end_pfn, struct zone *zone) { struct page *start_page; struct page *end_page; /* end_pfn is one past the range we are checking */ end_pfn--; if (!pfn_valid(end_pfn)) return NULL; start_page = pfn_to_online_page(start_pfn); if (!start_page) return NULL; if (page_zone(start_page) != zone) return NULL; end_page = pfn_to_page(end_pfn); /* This gives a shorter code than deriving page_zone(end_page) */ if (page_zone_id(start_page) != page_zone_id(end_page)) return NULL; return start_page; } /* * The order of subdivision here is critical for the IO subsystem. * Please do not alter this order without good reasons and regression * testing. Specifically, as large blocks of memory are subdivided, * the order in which smaller blocks are delivered depends on the order * they're subdivided in this function. This is the primary factor * influencing the order in which pages are delivered to the IO * subsystem according to empirical testing, and this is also justified * by considering the behavior of a buddy system containing a single * large block of memory acted on by a series of small allocations. * This behavior is a critical factor in sglist merging's success. * * -- nyc */ static inline void expand(struct zone *zone, struct page *page, int low, int high, int migratetype) { unsigned long size = 1 << high; unsigned long nr_added = 0; while (high > low) { high--; size >>= 1; VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]); /* * Mark as guard pages (or page), that will allow to * merge back to allocator when buddy will be freed. * Corresponding page table entries will not be touched, * pages will stay not present in virtual address space */ if (set_page_guard(zone, &page[size], high)) continue; __add_to_free_list(&page[size], zone, high, migratetype, false); set_buddy_order(&page[size], high); nr_added += size; } account_freepages(zone, nr_added, migratetype); } static void check_new_page_bad(struct page *page) { if (unlikely(page->flags & __PG_HWPOISON)) { /* Don't complain about hwpoisoned pages */ if (PageBuddy(page)) __ClearPageBuddy(page); return; } bad_page(page, page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP)); } /* * This page is about to be returned from the page allocator */ static bool check_new_page(struct page *page) { if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON))) return false; check_new_page_bad(page); return true; } static inline bool check_new_pages(struct page *page, unsigned int order) { if (is_check_pages_enabled()) { for (int i = 0; i < (1 << order); i++) { struct page *p = page + i; if (check_new_page(p)) return true; } } return false; } static inline bool should_skip_kasan_unpoison(gfp_t flags) { /* Don't skip if a software KASAN mode is enabled. */ if (IS_ENABLED(CONFIG_KASAN_GENERIC) || IS_ENABLED(CONFIG_KASAN_SW_TAGS)) return false; /* Skip, if hardware tag-based KASAN is not enabled. */ if (!kasan_hw_tags_enabled()) return true; /* * With hardware tag-based KASAN enabled, skip if this has been * requested via __GFP_SKIP_KASAN. */ return flags & __GFP_SKIP_KASAN; } static inline bool should_skip_init(gfp_t flags) { /* Don't skip, if hardware tag-based KASAN is not enabled. */ if (!kasan_hw_tags_enabled()) return false; /* For hardware tag-based KASAN, skip if requested. */ return (flags & __GFP_SKIP_ZERO); } inline void post_alloc_hook(struct page *page, unsigned int order, gfp_t gfp_flags) { bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags) && !should_skip_init(gfp_flags); bool zero_tags = init && (gfp_flags & __GFP_ZEROTAGS); int i; set_page_private(page, 0); set_page_refcounted(page); arch_alloc_page(page, order); debug_pagealloc_map_pages(page, 1 << order); /* * Page unpoisoning must happen before memory initialization. * Otherwise, the poison pattern will be overwritten for __GFP_ZERO * allocations and the page unpoisoning code will complain. */ kernel_unpoison_pages(page, 1 << order); /* * As memory initialization might be integrated into KASAN, * KASAN unpoisoning and memory initializion code must be * kept together to avoid discrepancies in behavior. */ /* * If memory tags should be zeroed * (which happens only when memory should be initialized as well). */ if (zero_tags) { /* Initialize both memory and memory tags. */ for (i = 0; i != 1 << order; ++i) tag_clear_highpage(page + i); /* Take note that memory was initialized by the loop above. */ init = false; } if (!should_skip_kasan_unpoison(gfp_flags) && kasan_unpoison_pages(page, order, init)) { /* Take note that memory was initialized by KASAN. */ if (kasan_has_integrated_init()) init = false; } else { /* * If memory tags have not been set by KASAN, reset the page * tags to ensure page_address() dereferencing does not fault. */ for (i = 0; i != 1 << order; ++i) page_kasan_tag_reset(page + i); } /* If memory is still not initialized, initialize it now. */ if (init) kernel_init_pages(page, 1 << order); set_page_owner(page, order, gfp_flags); page_table_check_alloc(page, order); pgalloc_tag_add(page, current, 1 << order); } static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags, unsigned int alloc_flags) { post_alloc_hook(page, order, gfp_flags); if (order && (gfp_flags & __GFP_COMP)) prep_compound_page(page, order); /* * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to * allocate the page. The expectation is that the caller is taking * steps that will free more memory. The caller should avoid the page * being used for !PFMEMALLOC purposes. */ if (alloc_flags & ALLOC_NO_WATERMARKS) set_page_pfmemalloc(page); else clear_page_pfmemalloc(page); } /* * Go through the free lists for the given migratetype and remove * the smallest available page from the freelists */ static __always_inline struct page *__rmqueue_smallest(struct zone *zone, unsigned int order, int migratetype) { unsigned int current_order; struct free_area *area; struct page *page; /* Find a page of the appropriate size in the preferred list */ for (current_order = order; current_order < NR_PAGE_ORDERS; ++current_order) { area = &(zone->free_area[current_order]); page = get_page_from_free_area(area, migratetype); if (!page) continue; del_page_from_free_list(page, zone, current_order, migratetype); expand(zone, page, order, current_order, migratetype); trace_mm_page_alloc_zone_locked(page, order, migratetype, pcp_allowed_order(order) && migratetype < MIGRATE_PCPTYPES); return page; } return NULL; } /* * This array describes the order lists are fallen back to when * the free lists for the desirable migrate type are depleted * * The other migratetypes do not have fallbacks. */ static int fallbacks[MIGRATE_PCPTYPES][MIGRATE_PCPTYPES - 1] = { [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE }, [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE }, [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE }, }; #ifdef CONFIG_CMA static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone, unsigned int order) { return __rmqueue_smallest(zone, order, MIGRATE_CMA); } #else static inline struct page *__rmqueue_cma_fallback(struct zone *zone, unsigned int order) { return NULL; } #endif /* * Change the type of a block and move all its free pages to that * type's freelist. */ static int __move_freepages_block(struct zone *zone, unsigned long start_pfn, int old_mt, int new_mt) { struct page *page; unsigned long pfn, end_pfn; unsigned int order; int pages_moved = 0; VM_WARN_ON(start_pfn & (pageblock_nr_pages - 1)); end_pfn = pageblock_end_pfn(start_pfn); for (pfn = start_pfn; pfn < end_pfn;) { page = pfn_to_page(pfn); if (!PageBuddy(page)) { pfn++; continue; } /* Make sure we are not inadvertently changing nodes */ VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); VM_BUG_ON_PAGE(page_zone(page) != zone, page); order = buddy_order(page); move_to_free_list(page, zone, order, old_mt, new_mt); pfn += 1 << order; pages_moved += 1 << order; } set_pageblock_migratetype(pfn_to_page(start_pfn), new_mt); return pages_moved; } static bool prep_move_freepages_block(struct zone *zone, struct page *page, unsigned long *start_pfn, int *num_free, int *num_movable) { unsigned long pfn, start, end; pfn = page_to_pfn(page); start = pageblock_start_pfn(pfn); end = pageblock_end_pfn(pfn); /* * The caller only has the lock for @zone, don't touch ranges * that straddle into other zones. While we could move part of * the range that's inside the zone, this call is usually * accompanied by other operations such as migratetype updates * which also should be locked. */ if (!zone_spans_pfn(zone, start)) return false; if (!zone_spans_pfn(zone, end - 1)) return false; *start_pfn = start; if (num_free) { *num_free = 0; *num_movable = 0; for (pfn = start; pfn < end;) { page = pfn_to_page(pfn); if (PageBuddy(page)) { int nr = 1 << buddy_order(page); *num_free += nr; pfn += nr; continue; } /* * We assume that pages that could be isolated for * migration are movable. But we don't actually try * isolating, as that would be expensive. */ if (PageLRU(page) || __PageMovable(page)) (*num_movable)++; pfn++; } } return true; } static int move_freepages_block(struct zone *zone, struct page *page, int old_mt, int new_mt) { unsigned long start_pfn; if (!prep_move_freepages_block(zone, page, &start_pfn, NULL, NULL)) return -1; return __move_freepages_block(zone, start_pfn, old_mt, new_mt); } #ifdef CONFIG_MEMORY_ISOLATION /* Look for a buddy that straddles start_pfn */ static unsigned long find_large_buddy(unsigned long start_pfn) { int order = 0; struct page *page; unsigned long pfn = start_pfn; while (!PageBuddy(page = pfn_to_page(pfn))) { /* Nothing found */ if (++order > MAX_PAGE_ORDER) return start_pfn; pfn &= ~0UL << order; } /* * Found a preceding buddy, but does it straddle? */ if (pfn + (1 << buddy_order(page)) > start_pfn) return pfn; /* Nothing found */ return start_pfn; } /* Split a multi-block free page into its individual pageblocks */ static void split_large_buddy(struct zone *zone, struct page *page, unsigned long pfn, int order) { unsigned long end_pfn = pfn + (1 << order); VM_WARN_ON_ONCE(order <= pageblock_order); VM_WARN_ON_ONCE(pfn & (pageblock_nr_pages - 1)); /* Caller removed page from freelist, buddy info cleared! */ VM_WARN_ON_ONCE(PageBuddy(page)); while (pfn != end_pfn) { int mt = get_pfnblock_migratetype(page, pfn); __free_one_page(page, pfn, zone, pageblock_order, mt, FPI_NONE); pfn += pageblock_nr_pages; page = pfn_to_page(pfn); } } /** * move_freepages_block_isolate - move free pages in block for page isolation * @zone: the zone * @page: the pageblock page * @migratetype: migratetype to set on the pageblock * * This is similar to move_freepages_block(), but handles the special * case encountered in page isolation, where the block of interest * might be part of a larger buddy spanning multiple pageblocks. * * Unlike the regular page allocator path, which moves pages while * stealing buddies off the freelist, page isolation is interested in * arbitrary pfn ranges that may have overlapping buddies on both ends. * * This function handles that. Straddling buddies are split into * individual pageblocks. Only the block of interest is moved. * * Returns %true if pages could be moved, %false otherwise. */ bool move_freepages_block_isolate(struct zone *zone, struct page *page, int migratetype) { unsigned long start_pfn, pfn; if (!prep_move_freepages_block(zone, page, &start_pfn, NULL, NULL)) return false; /* No splits needed if buddies can't span multiple blocks */ if (pageblock_order == MAX_PAGE_ORDER) goto move; /* We're a tail block in a larger buddy */ pfn = find_large_buddy(start_pfn); if (pfn != start_pfn) { struct page *buddy = pfn_to_page(pfn); int order = buddy_order(buddy); del_page_from_free_list(buddy, zone, order, get_pfnblock_migratetype(buddy, pfn)); set_pageblock_migratetype(page, migratetype); split_large_buddy(zone, buddy, pfn, order); return true; } /* We're the starting block of a larger buddy */ if (PageBuddy(page) && buddy_order(page) > pageblock_order) { int order = buddy_order(page); del_page_from_free_list(page, zone, order, get_pfnblock_migratetype(page, pfn)); set_pageblock_migratetype(page, migratetype); split_large_buddy(zone, page, pfn, order); return true; } move: __move_freepages_block(zone, start_pfn, get_pfnblock_migratetype(page, start_pfn), migratetype); return true; } #endif /* CONFIG_MEMORY_ISOLATION */ static void change_pageblock_range(struct page *pageblock_page, int start_order, int migratetype) { int nr_pageblocks = 1 << (start_order - pageblock_order); while (nr_pageblocks--) { set_pageblock_migratetype(pageblock_page, migratetype); pageblock_page += pageblock_nr_pages; } } /* * When we are falling back to another migratetype during allocation, try to * steal extra free pages from the same pageblocks to satisfy further * allocations, instead of polluting multiple pageblocks. * * If we are stealing a relatively large buddy page, it is likely there will * be more free pages in the pageblock, so try to steal them all. For * reclaimable and unmovable allocations, we steal regardless of page size, * as fragmentation caused by those allocations polluting movable pageblocks * is worse than movable allocations stealing from unmovable and reclaimable * pageblocks. */ static bool can_steal_fallback(unsigned int order, int start_mt) { /* * Leaving this order check is intended, although there is * relaxed order check in next check. The reason is that * we can actually steal whole pageblock if this condition met, * but, below check doesn't guarantee it and that is just heuristic * so could be changed anytime. */ if (order >= pageblock_order) return true; if (order >= pageblock_order / 2 || start_mt == MIGRATE_RECLAIMABLE || start_mt == MIGRATE_UNMOVABLE || page_group_by_mobility_disabled) return true; return false; } static inline bool boost_watermark(struct zone *zone) { unsigned long max_boost; if (!watermark_boost_factor) return false; /* * Don't bother in zones that are unlikely to produce results. * On small machines, including kdump capture kernels running * in a small area, boosting the watermark can cause an out of * memory situation immediately. */ if ((pageblock_nr_pages * 4) > zone_managed_pages(zone)) return false; max_boost = mult_frac(zone->_watermark[WMARK_HIGH], watermark_boost_factor, 10000); /* * high watermark may be uninitialised if fragmentation occurs * very early in boot so do not boost. We do not fall * through and boost by pageblock_nr_pages as failing * allocations that early means that reclaim is not going * to help and it may even be impossible to reclaim the * boosted watermark resulting in a hang. */ if (!max_boost) return false; max_boost = max(pageblock_nr_pages, max_boost); zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages, max_boost); return true; } /* * This function implements actual steal behaviour. If order is large enough, we * can claim the whole pageblock for the requested migratetype. If not, we check * the pageblock for constituent pages; if at least half of the pages are free * or compatible, we can still claim the whole block, so pages freed in the * future will be put on the correct free list. Otherwise, we isolate exactly * the order we need from the fallback block and leave its migratetype alone. */ static struct page * steal_suitable_fallback(struct zone *zone, struct page *page, int current_order, int order, int start_type, unsigned int alloc_flags, bool whole_block) { int free_pages, movable_pages, alike_pages; unsigned long start_pfn; int block_type; block_type = get_pageblock_migratetype(page); /* * This can happen due to races and we want to prevent broken * highatomic accounting. */ if (is_migrate_highatomic(block_type)) goto single_page; /* Take ownership for orders >= pageblock_order */ if (current_order >= pageblock_order) { del_page_from_free_list(page, zone, current_order, block_type); change_pageblock_range(page, current_order, start_type); expand(zone, page, order, current_order, start_type); return page; } /* * Boost watermarks to increase reclaim pressure to reduce the * likelihood of future fallbacks. Wake kswapd now as the node * may be balanced overall and kswapd will not wake naturally. */ if (boost_watermark(zone) && (alloc_flags & ALLOC_KSWAPD)) set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags); /* We are not allowed to try stealing from the whole block */ if (!whole_block) goto single_page; /* moving whole block can fail due to zone boundary conditions */ if (!prep_move_freepages_block(zone, page, &start_pfn, &free_pages, &movable_pages)) goto single_page; /* * Determine how many pages are compatible with our allocation. * For movable allocation, it's the number of movable pages which * we just obtained. For other types it's a bit more tricky. */ if (start_type == MIGRATE_MOVABLE) { alike_pages = movable_pages; } else { /* * If we are falling back a RECLAIMABLE or UNMOVABLE allocation * to MOVABLE pageblock, consider all non-movable pages as * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or * vice versa, be conservative since we can't distinguish the * exact migratetype of non-movable pages. */ if (block_type == MIGRATE_MOVABLE) alike_pages = pageblock_nr_pages - (free_pages + movable_pages); else alike_pages = 0; } /* * If a sufficient number of pages in the block are either free or of * compatible migratability as our allocation, claim the whole block. */ if (free_pages + alike_pages >= (1 << (pageblock_order-1)) || page_group_by_mobility_disabled) { __move_freepages_block(zone, start_pfn, block_type, start_type); return __rmqueue_smallest(zone, order, start_type); } single_page: del_page_from_free_list(page, zone, current_order, block_type); expand(zone, page, order, current_order, block_type); return page; } /* * Check whether there is a suitable fallback freepage with requested order. * If only_stealable is true, this function returns fallback_mt only if * we can steal other freepages all together. This would help to reduce * fragmentation due to mixed migratetype pages in one pageblock. */ int find_suitable_fallback(struct free_area *area, unsigned int order, int migratetype, bool only_stealable, bool *can_steal) { int i; int fallback_mt; if (area->nr_free == 0) return -1; *can_steal = false; for (i = 0; i < MIGRATE_PCPTYPES - 1 ; i++) { fallback_mt = fallbacks[migratetype][i]; if (free_area_empty(area, fallback_mt)) continue; if (can_steal_fallback(order, migratetype)) *can_steal = true; if (!only_stealable) return fallback_mt; if (*can_steal) return fallback_mt; } return -1; } /* * Reserve the pageblock(s) surrounding an allocation request for * exclusive use of high-order atomic allocations if there are no * empty page blocks that contain a page with a suitable order */ static void reserve_highatomic_pageblock(struct page *page, int order, struct zone *zone) { int mt; unsigned long max_managed, flags; /* * The number reserved as: minimum is 1 pageblock, maximum is * roughly 1% of a zone. But if 1% of a zone falls below a * pageblock size, then don't reserve any pageblocks. * Check is race-prone but harmless. */ if ((zone_managed_pages(zone) / 100) < pageblock_nr_pages) return; max_managed = ALIGN((zone_managed_pages(zone) / 100), pageblock_nr_pages); if (zone->nr_reserved_highatomic >= max_managed) return; spin_lock_irqsave(&zone->lock, flags); /* Recheck the nr_reserved_highatomic limit under the lock */ if (zone->nr_reserved_highatomic >= max_managed) goto out_unlock; /* Yoink! */ mt = get_pageblock_migratetype(page); /* Only reserve normal pageblocks (i.e., they can merge with others) */ if (!migratetype_is_mergeable(mt)) goto out_unlock; if (order < pageblock_order) { if (move_freepages_block(zone, page, mt, MIGRATE_HIGHATOMIC) == -1) goto out_unlock; zone->nr_reserved_highatomic += pageblock_nr_pages; } else { change_pageblock_range(page, order, MIGRATE_HIGHATOMIC); zone->nr_reserved_highatomic += 1 << order; } out_unlock: spin_unlock_irqrestore(&zone->lock, flags); } /* * Used when an allocation is about to fail under memory pressure. This * potentially hurts the reliability of high-order allocations when under * intense memory pressure but failed atomic allocations should be easier * to recover from than an OOM. * * If @force is true, try to unreserve pageblocks even though highatomic * pageblock is exhausted. */ static bool unreserve_highatomic_pageblock(const struct alloc_context *ac, bool force) { struct zonelist *zonelist = ac->zonelist; unsigned long flags; struct zoneref *z; struct zone *zone; struct page *page; int order; int ret; for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->highest_zoneidx, ac->nodemask) { /* * Preserve at least one pageblock unless memory pressure * is really high. */ if (!force && zone->nr_reserved_highatomic <= pageblock_nr_pages) continue; spin_lock_irqsave(&zone->lock, flags); for (order = 0; order < NR_PAGE_ORDERS; order++) { struct free_area *area = &(zone->free_area[order]); int mt; page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC); if (!page) continue; mt = get_pageblock_migratetype(page); /* * In page freeing path, migratetype change is racy so * we can counter several free pages in a pageblock * in this loop although we changed the pageblock type * from highatomic to ac->migratetype. So we should * adjust the count once. */ if (is_migrate_highatomic(mt)) { unsigned long size; /* * It should never happen but changes to * locking could inadvertently allow a per-cpu * drain to add pages to MIGRATE_HIGHATOMIC * while unreserving so be safe and watch for * underflows. */ size = max(pageblock_nr_pages, 1UL << order); size = min(size, zone->nr_reserved_highatomic); zone->nr_reserved_highatomic -= size; } /* * Convert to ac->migratetype and avoid the normal * pageblock stealing heuristics. Minimally, the caller * is doing the work and needs the pages. More * importantly, if the block was always converted to * MIGRATE_UNMOVABLE or another type then the number * of pageblocks that cannot be completely freed * may increase. */ if (order < pageblock_order) ret = move_freepages_block(zone, page, mt, ac->migratetype); else { move_to_free_list(page, zone, order, mt, ac->migratetype); change_pageblock_range(page, order, ac->migratetype); ret = 1; } /* * Reserving the block(s) already succeeded, * so this should not fail on zone boundaries. */ WARN_ON_ONCE(ret == -1); if (ret > 0) { spin_unlock_irqrestore(&zone->lock, flags); return ret; } } spin_unlock_irqrestore(&zone->lock, flags); } return false; } /* * Try finding a free buddy page on the fallback list and put it on the free * list of requested migratetype, possibly along with other pages from the same * block, depending on fragmentation avoidance heuristics. Returns true if * fallback was found so that __rmqueue_smallest() can grab it. * * The use of signed ints for order and current_order is a deliberate * deviation from the rest of this file, to make the for loop * condition simpler. */ static __always_inline struct page * __rmqueue_fallback(struct zone *zone, int order, int start_migratetype, unsigned int alloc_flags) { struct free_area *area; int current_order; int min_order = order; struct page *page; int fallback_mt; bool can_steal; /* * Do not steal pages from freelists belonging to other pageblocks * i.e. orders < pageblock_order. If there are no local zones free, * the zonelists will be reiterated without ALLOC_NOFRAGMENT. */ if (order < pageblock_order && alloc_flags & ALLOC_NOFRAGMENT) min_order = pageblock_order; /* * Find the largest available free page in the other list. This roughly * approximates finding the pageblock with the most free pages, which * would be too costly to do exactly. */ for (current_order = MAX_PAGE_ORDER; current_order >= min_order; --current_order) { area = &(zone->free_area[current_order]); fallback_mt = find_suitable_fallback(area, current_order, start_migratetype, false, &can_steal); if (fallback_mt == -1) continue; /* * We cannot steal all free pages from the pageblock and the * requested migratetype is movable. In that case it's better to * steal and split the smallest available page instead of the * largest available page, because even if the next movable * allocation falls back into a different pageblock than this * one, it won't cause permanent fragmentation. */ if (!can_steal && start_migratetype == MIGRATE_MOVABLE && current_order > order) goto find_smallest; goto do_steal; } return NULL; find_smallest: for (current_order = order; current_order < NR_PAGE_ORDERS; current_order++) { area = &(zone->free_area[current_order]); fallback_mt = find_suitable_fallback(area, current_order, start_migratetype, false, &can_steal); if (fallback_mt != -1) break; } /* * This should not happen - we already found a suitable fallback * when looking for the largest page. */ VM_BUG_ON(current_order > MAX_PAGE_ORDER); do_steal: page = get_page_from_free_area(area, fallback_mt); /* take off list, maybe claim block, expand remainder */ page = steal_suitable_fallback(zone, page, current_order, order, start_migratetype, alloc_flags, can_steal); trace_mm_page_alloc_extfrag(page, order, current_order, start_migratetype, fallback_mt); return page; } /* * Do the hard work of removing an element from the buddy allocator. * Call me with the zone->lock already held. */ static __always_inline struct page * __rmqueue(struct zone *zone, unsigned int order, int migratetype, unsigned int alloc_flags) { struct page *page; if (IS_ENABLED(CONFIG_CMA)) { /* * Balance movable allocations between regular and CMA areas by * allocating from CMA when over half of the zone's free memory * is in the CMA area. */ if (alloc_flags & ALLOC_CMA && zone_page_state(zone, NR_FREE_CMA_PAGES) > zone_page_state(zone, NR_FREE_PAGES) / 2) { page = __rmqueue_cma_fallback(zone, order); if (page) return page; } } page = __rmqueue_smallest(zone, order, migratetype); if (unlikely(!page)) { if (alloc_flags & ALLOC_CMA) page = __rmqueue_cma_fallback(zone, order); if (!page) page = __rmqueue_fallback(zone, order, migratetype, alloc_flags); } return page; } /* * Obtain a specified number of elements from the buddy allocator, all under * a single hold of the lock, for efficiency. Add them to the supplied list. * Returns the number of new pages which were placed at *list. */ static int rmqueue_bulk(struct zone *zone, unsigned int order, unsigned long count, struct list_head *list, int migratetype, unsigned int alloc_flags) { unsigned long flags; int i; spin_lock_irqsave(&zone->lock, flags); for (i = 0; i < count; ++i) { struct page *page = __rmqueue(zone, order, migratetype, alloc_flags); if (unlikely(page == NULL)) break; /* * Split buddy pages returned by expand() are received here in * physical page order. The page is added to the tail of * caller's list. From the callers perspective, the linked list * is ordered by page number under some conditions. This is * useful for IO devices that can forward direction from the * head, thus also in the physical page order. This is useful * for IO devices that can merge IO requests if the physical * pages are ordered properly. */ list_add_tail(&page->pcp_list, list); } spin_unlock_irqrestore(&zone->lock, flags); return i; } /* * Called from the vmstat counter updater to decay the PCP high. * Return whether there are addition works to do. */ int decay_pcp_high(struct zone *zone, struct per_cpu_pages *pcp) { int high_min, to_drain, batch; int todo = 0; high_min = READ_ONCE(pcp->high_min); batch = READ_ONCE(pcp->batch); /* * Decrease pcp->high periodically to try to free possible * idle PCP pages. And, avoid to free too many pages to * control latency. This caps pcp->high decrement too. */ if (pcp->high > high_min) { pcp->high = max3(pcp->count - (batch << CONFIG_PCP_BATCH_SCALE_MAX), pcp->high - (pcp->high >> 3), high_min); if (pcp->high > high_min) todo++; } to_drain = pcp->count - pcp->high; if (to_drain > 0) { spin_lock(&pcp->lock); free_pcppages_bulk(zone, to_drain, pcp, 0); spin_unlock(&pcp->lock); todo++; } return todo; } #ifdef CONFIG_NUMA /* * Called from the vmstat counter updater to drain pagesets of this * currently executing processor on remote nodes after they have * expired. */ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp) { int to_drain, batch; batch = READ_ONCE(pcp->batch); to_drain = min(pcp->count, batch); if (to_drain > 0) { spin_lock(&pcp->lock); free_pcppages_bulk(zone, to_drain, pcp, 0); spin_unlock(&pcp->lock); } } #endif /* * Drain pcplists of the indicated processor and zone. */ static void drain_pages_zone(unsigned int cpu, struct zone *zone) { struct per_cpu_pages *pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); int count; do { spin_lock(&pcp->lock); count = pcp->count; if (count) { int to_drain = min(count, pcp->batch << CONFIG_PCP_BATCH_SCALE_MAX); free_pcppages_bulk(zone, to_drain, pcp, 0); count -= to_drain; } spin_unlock(&pcp->lock); } while (count); } /* * Drain pcplists of all zones on the indicated processor. */ static void drain_pages(unsigned int cpu) { struct zone *zone; for_each_populated_zone(zone) { drain_pages_zone(cpu, zone); } } /* * Spill all of this CPU's per-cpu pages back into the buddy allocator. */ void drain_local_pages(struct zone *zone) { int cpu = smp_processor_id(); if (zone) drain_pages_zone(cpu, zone); else drain_pages(cpu); } /* * The implementation of drain_all_pages(), exposing an extra parameter to * drain on all cpus. * * drain_all_pages() is optimized to only execute on cpus where pcplists are * not empty. The check for non-emptiness can however race with a free to * pcplist that has not yet increased the pcp->count from 0 to 1. Callers * that need the guarantee that every CPU has drained can disable the * optimizing racy check. */ static void __drain_all_pages(struct zone *zone, bool force_all_cpus) { int cpu; /* * Allocate in the BSS so we won't require allocation in * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y */ static cpumask_t cpus_with_pcps; /* * Do not drain if one is already in progress unless it's specific to * a zone. Such callers are primarily CMA and memory hotplug and need * the drain to be complete when the call returns. */ if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) { if (!zone) return; mutex_lock(&pcpu_drain_mutex); } /* * We don't care about racing with CPU hotplug event * as offline notification will cause the notified * cpu to drain that CPU pcps and on_each_cpu_mask * disables preemption as part of its processing */ for_each_online_cpu(cpu) { struct per_cpu_pages *pcp; struct zone *z; bool has_pcps = false; if (force_all_cpus) { /* * The pcp.count check is racy, some callers need a * guarantee that no cpu is missed. */ has_pcps = true; } else if (zone) { pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); if (pcp->count) has_pcps = true; } else { for_each_populated_zone(z) { pcp = per_cpu_ptr(z->per_cpu_pageset, cpu); if (pcp->count) { has_pcps = true; break; } } } if (has_pcps) cpumask_set_cpu(cpu, &cpus_with_pcps); else cpumask_clear_cpu(cpu, &cpus_with_pcps); } for_each_cpu(cpu, &cpus_with_pcps) { if (zone) drain_pages_zone(cpu, zone); else drain_pages(cpu); } mutex_unlock(&pcpu_drain_mutex); } /* * Spill all the per-cpu pages from all CPUs back into the buddy allocator. * * When zone parameter is non-NULL, spill just the single zone's pages. */ void drain_all_pages(struct zone *zone) { __drain_all_pages(zone, false); } static int nr_pcp_free(struct per_cpu_pages *pcp, int batch, int high, bool free_high) { int min_nr_free, max_nr_free; /* Free as much as possible if batch freeing high-order pages. */ if (unlikely(free_high)) return min(pcp->count, batch << CONFIG_PCP_BATCH_SCALE_MAX); /* Check for PCP disabled or boot pageset */ if (unlikely(high < batch)) return 1; /* Leave at least pcp->batch pages on the list */ min_nr_free = batch; max_nr_free = high - batch; /* * Increase the batch number to the number of the consecutive * freed pages to reduce zone lock contention. */ batch = clamp_t(int, pcp->free_count, min_nr_free, max_nr_free); return batch; } static int nr_pcp_high(struct per_cpu_pages *pcp, struct zone *zone, int batch, bool free_high) { int high, high_min, high_max; high_min = READ_ONCE(pcp->high_min); high_max = READ_ONCE(pcp->high_max); high = pcp->high = clamp(pcp->high, high_min, high_max); if (unlikely(!high)) return 0; if (unlikely(free_high)) { pcp->high = max(high - (batch << CONFIG_PCP_BATCH_SCALE_MAX), high_min); return 0; } /* * If reclaim is active, limit the number of pages that can be * stored on pcp lists */ if (test_bit(ZONE_RECLAIM_ACTIVE, &zone->flags)) { int free_count = max_t(int, pcp->free_count, batch); pcp->high = max(high - free_count, high_min); return min(batch << 2, pcp->high); } if (high_min == high_max) return high; if (test_bit(ZONE_BELOW_HIGH, &zone->flags)) { int free_count = max_t(int, pcp->free_count, batch); pcp->high = max(high - free_count, high_min); high = max(pcp->count, high_min); } else if (pcp->count >= high) { int need_high = pcp->free_count + batch; /* pcp->high should be large enough to hold batch freed pages */ if (pcp->high < need_high) pcp->high = clamp(need_high, high_min, high_max); } return high; } static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, struct page *page, int migratetype, unsigned int order) { int high, batch; int pindex; bool free_high = false; /* * On freeing, reduce the number of pages that are batch allocated. * See nr_pcp_alloc() where alloc_factor is increased for subsequent * allocations. */ pcp->alloc_factor >>= 1; __count_vm_events(PGFREE, 1 << order); pindex = order_to_pindex(migratetype, order); list_add(&page->pcp_list, &pcp->lists[pindex]); pcp->count += 1 << order; batch = READ_ONCE(pcp->batch); /* * As high-order pages other than THP's stored on PCP can contribute * to fragmentation, limit the number stored when PCP is heavily * freeing without allocation. The remainder after bulk freeing * stops will be drained from vmstat refresh context. */ if (order && order <= PAGE_ALLOC_COSTLY_ORDER) { free_high = (pcp->free_count >= batch && (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) && (!(pcp->flags & PCPF_FREE_HIGH_BATCH) || pcp->count >= READ_ONCE(batch))); pcp->flags |= PCPF_PREV_FREE_HIGH_ORDER; } else if (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) { pcp->flags &= ~PCPF_PREV_FREE_HIGH_ORDER; } if (pcp->free_count < (batch << CONFIG_PCP_BATCH_SCALE_MAX)) pcp->free_count += (1 << order); high = nr_pcp_high(pcp, zone, batch, free_high); if (pcp->count >= high) { free_pcppages_bulk(zone, nr_pcp_free(pcp, batch, high, free_high), pcp, pindex); if (test_bit(ZONE_BELOW_HIGH, &zone->flags) && zone_watermark_ok(zone, 0, high_wmark_pages(zone), ZONE_MOVABLE, 0)) clear_bit(ZONE_BELOW_HIGH, &zone->flags); } } /* * Free a pcp page */ void free_unref_page(struct page *page, unsigned int order) { unsigned long __maybe_unused UP_flags; struct per_cpu_pages *pcp; struct zone *zone; unsigned long pfn = page_to_pfn(page); int migratetype; if (!pcp_allowed_order(order)) { __free_pages_ok(page, order, FPI_NONE); return; } if (!free_pages_prepare(page, order)) return; /* * We only track unmovable, reclaimable and movable on pcp lists. * Place ISOLATE pages on the isolated list because they are being * offlined but treat HIGHATOMIC and CMA as movable pages so we can * get those areas back if necessary. Otherwise, we may have to free * excessively into the page allocator */ migratetype = get_pfnblock_migratetype(page, pfn); if (unlikely(migratetype >= MIGRATE_PCPTYPES)) { if (unlikely(is_migrate_isolate(migratetype))) { free_one_page(page_zone(page), page, pfn, order, FPI_NONE); return; } migratetype = MIGRATE_MOVABLE; } zone = page_zone(page); pcp_trylock_prepare(UP_flags); pcp = pcp_spin_trylock(zone->per_cpu_pageset); if (pcp) { free_unref_page_commit(zone, pcp, page, migratetype, order); pcp_spin_unlock(pcp); } else { free_one_page(zone, page, pfn, order, FPI_NONE); } pcp_trylock_finish(UP_flags); } /* * Free a batch of folios */ void free_unref_folios(struct folio_batch *folios) { unsigned long __maybe_unused UP_flags; struct per_cpu_pages *pcp = NULL; struct zone *locked_zone = NULL; int i, j; /* Prepare folios for freeing */ for (i = 0, j = 0; i < folios->nr; i++) { struct folio *folio = folios->folios[i]; unsigned long pfn = folio_pfn(folio); unsigned int order = folio_order(folio); folio_undo_large_rmappable(folio); if (!free_pages_prepare(&folio->page, order)) continue; /* * Free orders not handled on the PCP directly to the * allocator. */ if (!pcp_allowed_order(order)) { free_one_page(folio_zone(folio), &folio->page, pfn, order, FPI_NONE); continue; } folio->private = (void *)(unsigned long)order; if (j != i) folios->folios[j] = folio; j++; } folios->nr = j; for (i = 0; i < folios->nr; i++) { struct folio *folio = folios->folios[i]; struct zone *zone = folio_zone(folio); unsigned long pfn = folio_pfn(folio); unsigned int order = (unsigned long)folio->private; int migratetype; folio->private = NULL; migratetype = get_pfnblock_migratetype(&folio->page, pfn); /* Different zone requires a different pcp lock */ if (zone != locked_zone || is_migrate_isolate(migratetype)) { if (pcp) { pcp_spin_unlock(pcp); pcp_trylock_finish(UP_flags); locked_zone = NULL; pcp = NULL; } /* * Free isolated pages directly to the * allocator, see comment in free_unref_page. */ if (is_migrate_isolate(migratetype)) { free_one_page(zone, &folio->page, pfn, order, FPI_NONE); continue; } /* * trylock is necessary as folios may be getting freed * from IRQ or SoftIRQ context after an IO completion. */ pcp_trylock_prepare(UP_flags); pcp = pcp_spin_trylock(zone->per_cpu_pageset); if (unlikely(!pcp)) { pcp_trylock_finish(UP_flags); free_one_page(zone, &folio->page, pfn, order, FPI_NONE); continue; } locked_zone = zone; } /* * Non-isolated types over MIGRATE_PCPTYPES get added * to the MIGRATE_MOVABLE pcp list. */ if (unlikely(migratetype >= MIGRATE_PCPTYPES)) migratetype = MIGRATE_MOVABLE; trace_mm_page_free_batched(&folio->page); free_unref_page_commit(zone, pcp, &folio->page, migratetype, order); } if (pcp) { pcp_spin_unlock(pcp); pcp_trylock_finish(UP_flags); } folio_batch_reinit(folios); } /* * split_page takes a non-compound higher-order page, and splits it into * n (1<<order) sub-pages: page[0..n] * Each sub-page must be freed individually. * * Note: this is probably too low level an operation for use in drivers. * Please consult with lkml before using this in your driver. */ void split_page(struct page *page, unsigned int order) { int i; VM_BUG_ON_PAGE(PageCompound(page), page); VM_BUG_ON_PAGE(!page_count(page), page); for (i = 1; i < (1 << order); i++) set_page_refcounted(page + i); split_page_owner(page, order, 0); pgalloc_tag_split(page, 1 << order); split_page_memcg(page, order, 0); } EXPORT_SYMBOL_GPL(split_page); int __isolate_free_page(struct page *page, unsigned int order) { struct zone *zone = page_zone(page); int mt = get_pageblock_migratetype(page); if (!is_migrate_isolate(mt)) { unsigned long watermark; /* * Obey watermarks as if the page was being allocated. We can * emulate a high-order watermark check with a raised order-0 * watermark, because we already know our high-order page * exists. */ watermark = zone->_watermark[WMARK_MIN] + (1UL << order); if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA)) return 0; } del_page_from_free_list(page, zone, order, mt); /* * Set the pageblock if the isolated page is at least half of a * pageblock */ if (order >= pageblock_order - 1) { struct page *endpage = page + (1 << order) - 1; for (; page < endpage; page += pageblock_nr_pages) { int mt = get_pageblock_migratetype(page); /* * Only change normal pageblocks (i.e., they can merge * with others) */ if (migratetype_is_mergeable(mt)) move_freepages_block(zone, page, mt, MIGRATE_MOVABLE); } } return 1UL << order; } /** * __putback_isolated_page - Return a now-isolated page back where we got it * @page: Page that was isolated * @order: Order of the isolated page * @mt: The page's pageblock's migratetype * * This function is meant to return a page pulled from the free lists via * __isolate_free_page back to the free lists they were pulled from. */ void __putback_isolated_page(struct page *page, unsigned int order, int mt) { struct zone *zone = page_zone(page); /* zone lock should be held when this function is called */ lockdep_assert_held(&zone->lock); /* Return isolated page to tail of freelist. */ __free_one_page(page, page_to_pfn(page), zone, order, mt, FPI_SKIP_REPORT_NOTIFY | FPI_TO_TAIL); } /* * Update NUMA hit/miss statistics */ static inline void zone_statistics(struct zone *preferred_zone, struct zone *z, long nr_account) { #ifdef CONFIG_NUMA enum numa_stat_item local_stat = NUMA_LOCAL; /* skip numa counters update if numa stats is disabled */ if (!static_branch_likely(&vm_numa_stat_key)) return; if (zone_to_nid(z) != numa_node_id()) local_stat = NUMA_OTHER; if (zone_to_nid(z) == zone_to_nid(preferred_zone)) __count_numa_events(z, NUMA_HIT, nr_account); else { __count_numa_events(z, NUMA_MISS, nr_account); __count_numa_events(preferred_zone, NUMA_FOREIGN, nr_account); } __count_numa_events(z, local_stat, nr_account); #endif } static __always_inline struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone, unsigned int order, unsigned int alloc_flags, int migratetype) { struct page *page; unsigned long flags; do { page = NULL; spin_lock_irqsave(&zone->lock, flags); if (alloc_flags & ALLOC_HIGHATOMIC) page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC); if (!page) { page = __rmqueue(zone, order, migratetype, alloc_flags); /* * If the allocation fails, allow OOM handling access * to HIGHATOMIC reserves as failing now is worse than * failing a high-order atomic allocation in the * future. */ if (!page && (alloc_flags & ALLOC_OOM)) page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC); if (!page) { spin_unlock_irqrestore(&zone->lock, flags); return NULL; } } spin_unlock_irqrestore(&zone->lock, flags); } while (check_new_pages(page, order)); __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order); zone_statistics(preferred_zone, zone, 1); return page; } static int nr_pcp_alloc(struct per_cpu_pages *pcp, struct zone *zone, int order) { int high, base_batch, batch, max_nr_alloc; int high_max, high_min; base_batch = READ_ONCE(pcp->batch); high_min = READ_ONCE(pcp->high_min); high_max = READ_ONCE(pcp->high_max); high = pcp->high = clamp(pcp->high, high_min, high_max); /* Check for PCP disabled or boot pageset */ if (unlikely(high < base_batch)) return 1; if (order) batch = base_batch; else batch = (base_batch << pcp->alloc_factor); /* * If we had larger pcp->high, we could avoid to allocate from * zone. */ if (high_min != high_max && !test_bit(ZONE_BELOW_HIGH, &zone->flags)) high = pcp->high = min(high + batch, high_max); if (!order) { max_nr_alloc = max(high - pcp->count - base_batch, base_batch); /* * Double the number of pages allocated each time there is * subsequent allocation of order-0 pages without any freeing. */ if (batch <= max_nr_alloc && pcp->alloc_factor < CONFIG_PCP_BATCH_SCALE_MAX) pcp->alloc_factor++; batch = min(batch, max_nr_alloc); } /* * Scale batch relative to order if batch implies free pages * can be stored on the PCP. Batch can be 1 for small zones or * for boot pagesets which should never store free pages as * the pages may belong to arbitrary zones. */ if (batch > 1) batch = max(batch >> order, 2); return batch; } /* Remove page from the per-cpu list, caller must protect the list */ static inline struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order, int migratetype, unsigned int alloc_flags, struct per_cpu_pages *pcp, struct list_head *list) { struct page *page; do { if (list_empty(list)) { int batch = nr_pcp_alloc(pcp, zone, order); int alloced; alloced = rmqueue_bulk(zone, order, batch, list, migratetype, alloc_flags); pcp->count += alloced << order; if (unlikely(list_empty(list))) return NULL; } page = list_first_entry(list, struct page, pcp_list); list_del(&page->pcp_list); pcp->count -= 1 << order; } while (check_new_pages(page, order)); return page; } /* Lock and remove page from the per-cpu list */ static struct page *rmqueue_pcplist(struct zone *preferred_zone, struct zone *zone, unsigned int order, int migratetype, unsigned int alloc_flags) { struct per_cpu_pages *pcp; struct list_head *list; struct page *page; unsigned long __maybe_unused UP_flags; /* spin_trylock may fail due to a parallel drain or IRQ reentrancy. */ pcp_trylock_prepare(UP_flags); pcp = pcp_spin_trylock(zone->per_cpu_pageset); if (!pcp) { pcp_trylock_finish(UP_flags); return NULL; } /* * On allocation, reduce the number of pages that are batch freed. * See nr_pcp_free() where free_factor is increased for subsequent * frees. */ pcp->free_count >>= 1; list = &pcp->lists[order_to_pindex(migratetype, order)]; page = __rmqueue_pcplist(zone, order, migratetype, alloc_flags, pcp, list); pcp_spin_unlock(pcp); pcp_trylock_finish(UP_flags); if (page) { __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order); zone_statistics(preferred_zone, zone, 1); } return page; } /* * Allocate a page from the given zone. * Use pcplists for THP or "cheap" high-order allocations. */ /* * Do not instrument rmqueue() with KMSAN. This function may call * __msan_poison_alloca() through a call to set_pfnblock_flags_mask(). * If __msan_poison_alloca() attempts to allocate pages for the stack depot, it * may call rmqueue() again, which will result in a deadlock. */ __no_sanitize_memory static inline struct page *rmqueue(struct zone *preferred_zone, struct zone *zone, unsigned int order, gfp_t gfp_flags, unsigned int alloc_flags, int migratetype) { struct page *page; /* * We most definitely don't want callers attempting to * allocate greater than order-1 page units with __GFP_NOFAIL. */ WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1)); if (likely(pcp_allowed_order(order))) { page = rmqueue_pcplist(preferred_zone, zone, order, migratetype, alloc_flags); if (likely(page)) goto out; } page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags, migratetype); out: /* Separate test+clear to avoid unnecessary atomics */ if ((alloc_flags & ALLOC_KSWAPD) && unlikely(test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags))) { clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags); wakeup_kswapd(zone, 0, 0, zone_idx(zone)); } VM_BUG_ON_PAGE(page && bad_range(zone, page), page); return page; } static inline long __zone_watermark_unusable_free(struct zone *z, unsigned int order, unsigned int alloc_flags) { long unusable_free = (1 << order) - 1; /* * If the caller does not have rights to reserves below the min * watermark then subtract the high-atomic reserves. This will * over-estimate the size of the atomic reserve but it avoids a search. */ if (likely(!(alloc_flags & ALLOC_RESERVES))) unusable_free += z->nr_reserved_highatomic; #ifdef CONFIG_CMA /* If allocation can't use CMA areas don't use free CMA pages */ if (!(alloc_flags & ALLOC_CMA)) unusable_free += zone_page_state(z, NR_FREE_CMA_PAGES); #endif return unusable_free; } /* * Return true if free base pages are above 'mark'. For high-order checks it * will return true of the order-0 watermark is reached and there is at least * one free page of a suitable size. Checking now avoids taking the zone lock * to check in the allocation paths if no pages are free. */ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, int highest_zoneidx, unsigned int alloc_flags, long free_pages) { long min = mark; int o; /* free_pages may go negative - that's OK */ free_pages -= __zone_watermark_unusable_free(z, order, alloc_flags); if (unlikely(alloc_flags & ALLOC_RESERVES)) { /* * __GFP_HIGH allows access to 50% of the min reserve as well * as OOM. */ if (alloc_flags & ALLOC_MIN_RESERVE) { min -= min / 2; /* * Non-blocking allocations (e.g. GFP_ATOMIC) can * access more reserves than just __GFP_HIGH. Other * non-blocking allocations requests such as GFP_NOWAIT * or (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) do not get * access to the min reserve. */ if (alloc_flags & ALLOC_NON_BLOCK) min -= min / 4; } /* * OOM victims can try even harder than the normal reserve * users on the grounds that it's definitely going to be in * the exit path shortly and free memory. Any allocation it * makes during the free path will be small and short-lived. */ if (alloc_flags & ALLOC_OOM) min -= min / 2; } /* * Check watermarks for an order-0 allocation request. If these * are not met, then a high-order request also cannot go ahead * even if a suitable page happened to be free. */ if (free_pages <= min + z->lowmem_reserve[highest_zoneidx]) return false; /* If this is an order-0 request then the watermark is fine */ if (!order) return true; /* For a high-order request, check at least one suitable page is free */ for (o = order; o < NR_PAGE_ORDERS; o++) { struct free_area *area = &z->free_area[o]; int mt; if (!area->nr_free) continue; for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) { if (!free_area_empty(area, mt)) return true; } #ifdef CONFIG_CMA if ((alloc_flags & ALLOC_CMA) && !free_area_empty(area, MIGRATE_CMA)) { return true; } #endif if ((alloc_flags & (ALLOC_HIGHATOMIC|ALLOC_OOM)) && !free_area_empty(area, MIGRATE_HIGHATOMIC)) { return true; } } return false; } bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, int highest_zoneidx, unsigned int alloc_flags) { return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags, zone_page_state(z, NR_FREE_PAGES)); } static inline bool zone_watermark_fast(struct zone *z, unsigned int order, unsigned long mark, int highest_zoneidx, unsigned int alloc_flags, gfp_t gfp_mask) { long free_pages; free_pages = zone_page_state(z, NR_FREE_PAGES); /* * Fast check for order-0 only. If this fails then the reserves * need to be calculated. */ if (!order) { long usable_free; long reserved; usable_free = free_pages; reserved = __zone_watermark_unusable_free(z, 0, alloc_flags); /* reserved may over estimate high-atomic reserves. */ usable_free -= min(usable_free, reserved); if (usable_free > mark + z->lowmem_reserve[highest_zoneidx]) return true; } if (__zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags, free_pages)) return true; /* * Ignore watermark boosting for __GFP_HIGH order-0 allocations * when checking the min watermark. The min watermark is the * point where boosting is ignored so that kswapd is woken up * when below the low watermark. */ if (unlikely(!order && (alloc_flags & ALLOC_MIN_RESERVE) && z->watermark_boost && ((alloc_flags & ALLOC_WMARK_MASK) == WMARK_MIN))) { mark = z->_watermark[WMARK_MIN]; return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags, free_pages); } return false; } bool zone_watermark_ok_safe(struct zone *z, unsigned int order, unsigned long mark, int highest_zoneidx) { long free_pages = zone_page_state(z, NR_FREE_PAGES); if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark) free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES); return __zone_watermark_ok(z, order, mark, highest_zoneidx, 0, free_pages); } #ifdef CONFIG_NUMA int __read_mostly node_reclaim_distance = RECLAIM_DISTANCE; static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) { return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <= node_reclaim_distance; } #else /* CONFIG_NUMA */ static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) { return true; } #endif /* CONFIG_NUMA */ /* * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid * fragmentation is subtle. If the preferred zone was HIGHMEM then * premature use of a lower zone may cause lowmem pressure problems that * are worse than fragmentation. If the next zone is ZONE_DMA then it is * probably too small. It only makes sense to spread allocations to avoid * fragmentation between the Normal and DMA32 zones. */ static inline unsigned int alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask) { unsigned int alloc_flags; /* * __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD * to save a branch. */ alloc_flags = (__force int) (gfp_mask & __GFP_KSWAPD_RECLAIM); #ifdef CONFIG_ZONE_DMA32 if (!zone) return alloc_flags; if (zone_idx(zone) != ZONE_NORMAL) return alloc_flags; /* * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and * the pointer is within zone->zone_pgdat->node_zones[]. Also assume * on UMA that if Normal is populated then so is DMA32. */ BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1); if (nr_online_nodes > 1 && !populated_zone(--zone)) return alloc_flags; alloc_flags |= ALLOC_NOFRAGMENT; #endif /* CONFIG_ZONE_DMA32 */ return alloc_flags; } /* Must be called after current_gfp_context() which can change gfp_mask */ static inline unsigned int gfp_to_alloc_flags_cma(gfp_t gfp_mask, unsigned int alloc_flags) { #ifdef CONFIG_CMA if (gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE) alloc_flags |= ALLOC_CMA; #endif return alloc_flags; } /* * get_page_from_freelist goes through the zonelist trying to allocate * a page. */ static struct page * get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, const struct alloc_context *ac) { struct zoneref *z; struct zone *zone; struct pglist_data *last_pgdat = NULL; bool last_pgdat_dirty_ok = false; bool no_fallback; retry: /* * Scan zonelist, looking for a zone with enough free. * See also cpuset_node_allowed() comment in kernel/cgroup/cpuset.c. */ no_fallback = alloc_flags & ALLOC_NOFRAGMENT; z = ac->preferred_zoneref; for_next_zone_zonelist_nodemask(zone, z, ac->highest_zoneidx, ac->nodemask) { struct page *page; unsigned long mark; if (cpusets_enabled() && (alloc_flags & ALLOC_CPUSET) && !__cpuset_zone_allowed(zone, gfp_mask)) continue; /* * When allocating a page cache page for writing, we * want to get it from a node that is within its dirty * limit, such that no single node holds more than its * proportional share of globally allowed dirty pages. * The dirty limits take into account the node's * lowmem reserves and high watermark so that kswapd * should be able to balance it without having to * write pages from its LRU list. * * XXX: For now, allow allocations to potentially * exceed the per-node dirty limit in the slowpath * (spread_dirty_pages unset) before going into reclaim, * which is important when on a NUMA setup the allowed * nodes are together not big enough to reach the * global limit. The proper fix for these situations * will require awareness of nodes in the * dirty-throttling and the flusher threads. */ if (ac->spread_dirty_pages) { if (last_pgdat != zone->zone_pgdat) { last_pgdat = zone->zone_pgdat; last_pgdat_dirty_ok = node_dirty_ok(zone->zone_pgdat); } if (!last_pgdat_dirty_ok) continue; } if (no_fallback && nr_online_nodes > 1 && zone != ac->preferred_zoneref->zone) { int local_nid; /* * If moving to a remote node, retry but allow * fragmenting fallbacks. Locality is more important * than fragmentation avoidance. */ local_nid = zone_to_nid(ac->preferred_zoneref->zone); if (zone_to_nid(zone) != local_nid) { alloc_flags &= ~ALLOC_NOFRAGMENT; goto retry; } } cond_accept_memory(zone, order); /* * Detect whether the number of free pages is below high * watermark. If so, we will decrease pcp->high and free * PCP pages in free path to reduce the possibility of * premature page reclaiming. Detection is done here to * avoid to do that in hotter free path. */ if (test_bit(ZONE_BELOW_HIGH, &zone->flags)) goto check_alloc_wmark; mark = high_wmark_pages(zone); if (zone_watermark_fast(zone, order, mark, ac->highest_zoneidx, alloc_flags, gfp_mask)) goto try_this_zone; else set_bit(ZONE_BELOW_HIGH, &zone->flags); check_alloc_wmark: mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK); if (!zone_watermark_fast(zone, order, mark, ac->highest_zoneidx, alloc_flags, gfp_mask)) { int ret; if (cond_accept_memory(zone, order)) goto try_this_zone; #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT /* * Watermark failed for this zone, but see if we can * grow this zone if it contains deferred pages. */ if (deferred_pages_enabled()) { if (_deferred_grow_zone(zone, order)) goto try_this_zone; } #endif /* Checked here to keep the fast path fast */ BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK); if (alloc_flags & ALLOC_NO_WATERMARKS) goto try_this_zone; if (!node_reclaim_enabled() || !zone_allows_reclaim(ac->preferred_zoneref->zone, zone)) continue; ret = node_reclaim(zone->zone_pgdat, gfp_mask, order); switch (ret) { case NODE_RECLAIM_NOSCAN: /* did not scan */ continue; case NODE_RECLAIM_FULL: /* scanned but unreclaimable */ continue; default: /* did we reclaim enough */ if (zone_watermark_ok(zone, order, mark, ac->highest_zoneidx, alloc_flags)) goto try_this_zone; continue; } } try_this_zone: page = rmqueue(ac->preferred_zoneref->zone, zone, order, gfp_mask, alloc_flags, ac->migratetype); if (page) { prep_new_page(page, order, gfp_mask, alloc_flags); /* * If this is a high-order atomic allocation then check * if the pageblock should be reserved for the future */ if (unlikely(alloc_flags & ALLOC_HIGHATOMIC)) reserve_highatomic_pageblock(page, order, zone); return page; } else { if (cond_accept_memory(zone, order)) goto try_this_zone; #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT /* Try again if zone has deferred pages */ if (deferred_pages_enabled()) { if (_deferred_grow_zone(zone, order)) goto try_this_zone; } #endif } } /* * It's possible on a UMA machine to get through all zones that are * fragmented. If avoiding fragmentation, reset and try again. */ if (no_fallback) { alloc_flags &= ~ALLOC_NOFRAGMENT; goto retry; } return NULL; } static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask) { unsigned int filter = SHOW_MEM_FILTER_NODES; /* * This documents exceptions given to allocations in certain * contexts that are allowed to allocate outside current's set * of allowed nodes. */ if (!(gfp_mask & __GFP_NOMEMALLOC)) if (tsk_is_oom_victim(current) || (current->flags & (PF_MEMALLOC | PF_EXITING))) filter &= ~SHOW_MEM_FILTER_NODES; if (!in_task() || !(gfp_mask & __GFP_DIRECT_RECLAIM)) filter &= ~SHOW_MEM_FILTER_NODES; __show_mem(filter, nodemask, gfp_zone(gfp_mask)); } void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...) { struct va_format vaf; va_list args; static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1); if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) || ((gfp_mask & __GFP_DMA) && !has_managed_dma())) return; va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl", current->comm, &vaf, gfp_mask, &gfp_mask, nodemask_pr_args(nodemask)); va_end(args); cpuset_print_current_mems_allowed(); pr_cont("\n"); dump_stack(); warn_alloc_show_mem(gfp_mask, nodemask); } static inline struct page * __alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order, unsigned int alloc_flags, const struct alloc_context *ac) { struct page *page; page = get_page_from_freelist(gfp_mask, order, alloc_flags|ALLOC_CPUSET, ac); /* * fallback to ignore cpuset restriction if our nodes * are depleted */ if (!page) page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); return page; } static inline struct page * __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, const struct alloc_context *ac, unsigned long *did_some_progress) { struct oom_control oc = { .zonelist = ac->zonelist, .nodemask = ac->nodemask, .memcg = NULL, .gfp_mask = gfp_mask, .order = order, }; struct page *page; *did_some_progress = 0; /* * Acquire the oom lock. If that fails, somebody else is * making progress for us. */ if (!mutex_trylock(&oom_lock)) { *did_some_progress = 1; schedule_timeout_uninterruptible(1); return NULL; } /* * Go through the zonelist yet one more time, keep very high watermark * here, this is only to catch a parallel oom killing, we must fail if * we're still under heavy pressure. But make sure that this reclaim * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY * allocation which will never fail due to oom_lock already held. */ page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) & ~__GFP_DIRECT_RECLAIM, order, ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac); if (page) goto out; /* Coredumps can quickly deplete all memory reserves */ if (current->flags & PF_DUMPCORE) goto out; /* The OOM killer will not help higher order allocs */ if (order > PAGE_ALLOC_COSTLY_ORDER) goto out; /* * We have already exhausted all our reclaim opportunities without any * success so it is time to admit defeat. We will skip the OOM killer * because it is very likely that the caller has a more reasonable * fallback than shooting a random task. * * The OOM killer may not free memory on a specific node. */ if (gfp_mask & (__GFP_RETRY_MAYFAIL | __GFP_THISNODE)) goto out; /* The OOM killer does not needlessly kill tasks for lowmem */ if (ac->highest_zoneidx < ZONE_NORMAL) goto out; if (pm_suspended_storage()) goto out; /* * XXX: GFP_NOFS allocations should rather fail than rely on * other request to make a forward progress. * We are in an unfortunate situation where out_of_memory cannot * do much for this context but let's try it to at least get * access to memory reserved if the current task is killed (see * out_of_memory). Once filesystems are ready to handle allocation * failures more gracefully we should just bail out here. */ /* Exhausted what can be done so it's blame time */ if (out_of_memory(&oc) || WARN_ON_ONCE_GFP(gfp_mask & __GFP_NOFAIL, gfp_mask)) { *did_some_progress = 1; /* * Help non-failing allocations by giving them access to memory * reserves */ if (gfp_mask & __GFP_NOFAIL) page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_NO_WATERMARKS, ac); } out: mutex_unlock(&oom_lock); return page; } /* * Maximum number of compaction retries with a progress before OOM * killer is consider as the only way to move forward. */ #define MAX_COMPACT_RETRIES 16 #ifdef CONFIG_COMPACTION /* Try memory compaction for high-order allocations before reclaim */ static struct page * __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, unsigned int alloc_flags, const struct alloc_context *ac, enum compact_priority prio, enum compact_result *compact_result) { struct page *page = NULL; unsigned long pflags; unsigned int noreclaim_flag; if (!order) return NULL; psi_memstall_enter(&pflags); delayacct_compact_start(); noreclaim_flag = memalloc_noreclaim_save(); *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac, prio, &page); memalloc_noreclaim_restore(noreclaim_flag); psi_memstall_leave(&pflags); delayacct_compact_end(); if (*compact_result == COMPACT_SKIPPED) return NULL; /* * At least in one zone compaction wasn't deferred or skipped, so let's * count a compaction stall */ count_vm_event(COMPACTSTALL); /* Prep a captured page if available */ if (page) prep_new_page(page, order, gfp_mask, alloc_flags); /* Try get a page from the freelist if available */ if (!page) page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); if (page) { struct zone *zone = page_zone(page); zone->compact_blockskip_flush = false; compaction_defer_reset(zone, order, true); count_vm_event(COMPACTSUCCESS); return page; } /* * It's bad if compaction run occurs and fails. The most likely reason * is that pages exist, but not enough to satisfy watermarks. */ count_vm_event(COMPACTFAIL); cond_resched(); return NULL; } static inline bool should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, enum compact_result compact_result, enum compact_priority *compact_priority, int *compaction_retries) { int max_retries = MAX_COMPACT_RETRIES; int min_priority; bool ret = false; int retries = *compaction_retries; enum compact_priority priority = *compact_priority; if (!order) return false; if (fatal_signal_pending(current)) return false; /* * Compaction was skipped due to a lack of free order-0 * migration targets. Continue if reclaim can help. */ if (compact_result == COMPACT_SKIPPED) { ret = compaction_zonelist_suitable(ac, order, alloc_flags); goto out; } /* * Compaction managed to coalesce some page blocks, but the * allocation failed presumably due to a race. Retry some. */ if (compact_result == COMPACT_SUCCESS) { /* * !costly requests are much more important than * __GFP_RETRY_MAYFAIL costly ones because they are de * facto nofail and invoke OOM killer to move on while * costly can fail and users are ready to cope with * that. 1/4 retries is rather arbitrary but we would * need much more detailed feedback from compaction to * make a better decision. */ if (order > PAGE_ALLOC_COSTLY_ORDER) max_retries /= 4; if (++(*compaction_retries) <= max_retries) { ret = true; goto out; } } /* * Compaction failed. Retry with increasing priority. */ min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ? MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY; if (*compact_priority > min_priority) { (*compact_priority)--; *compaction_retries = 0; ret = true; } out: trace_compact_retry(order, priority, compact_result, retries, max_retries, ret); return ret; } #else static inline struct page * __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, unsigned int alloc_flags, const struct alloc_context *ac, enum compact_priority prio, enum compact_result *compact_result) { *compact_result = COMPACT_SKIPPED; return NULL; } static inline bool should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags, enum compact_result compact_result, enum compact_priority *compact_priority, int *compaction_retries) { struct zone *zone; struct zoneref *z; if (!order || order > PAGE_ALLOC_COSTLY_ORDER) return false; /* * There are setups with compaction disabled which would prefer to loop * inside the allocator rather than hit the oom killer prematurely. * Let's give them a good hope and keep retrying while the order-0 * watermarks are OK. */ for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->highest_zoneidx, ac->nodemask) { if (zone_watermark_ok(zone, 0, min_wmark_pages(zone), ac->highest_zoneidx, alloc_flags)) return true; } return false; } #endif /* CONFIG_COMPACTION */ #ifdef CONFIG_LOCKDEP static struct lockdep_map __fs_reclaim_map = STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map); static bool __need_reclaim(gfp_t gfp_mask) { /* no reclaim without waiting on it */ if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) return false; /* this guy won't enter reclaim */ if (current->flags & PF_MEMALLOC) return false; if (gfp_mask & __GFP_NOLOCKDEP) return false; return true; } void __fs_reclaim_acquire(unsigned long ip) { lock_acquire_exclusive(&__fs_reclaim_map, 0, 0, NULL, ip); } void __fs_reclaim_release(unsigned long ip) { lock_release(&__fs_reclaim_map, ip); } void fs_reclaim_acquire(gfp_t gfp_mask) { gfp_mask = current_gfp_context(gfp_mask); if (__need_reclaim(gfp_mask)) { if (gfp_mask & __GFP_FS) __fs_reclaim_acquire(_RET_IP_); #ifdef CONFIG_MMU_NOTIFIER lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); lock_map_release(&__mmu_notifier_invalidate_range_start_map); #endif } } EXPORT_SYMBOL_GPL(fs_reclaim_acquire); void fs_reclaim_release(gfp_t gfp_mask) { gfp_mask = current_gfp_context(gfp_mask); if (__need_reclaim(gfp_mask)) { if (gfp_mask & __GFP_FS) __fs_reclaim_release(_RET_IP_); } } EXPORT_SYMBOL_GPL(fs_reclaim_release); #endif /* * Zonelists may change due to hotplug during allocation. Detect when zonelists * have been rebuilt so allocation retries. Reader side does not lock and * retries the allocation if zonelist changes. Writer side is protected by the * embedded spin_lock. */ static DEFINE_SEQLOCK(zonelist_update_seq); static unsigned int zonelist_iter_begin(void) { if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) return read_seqbegin(&zonelist_update_seq); return 0; } static unsigned int check_retry_zonelist(unsigned int seq) { if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) return read_seqretry(&zonelist_update_seq, seq); return seq; } /* Perform direct synchronous page reclaim */ static unsigned long __perform_reclaim(gfp_t gfp_mask, unsigned int order, const struct alloc_context *ac) { unsigned int noreclaim_flag; unsigned long progress; cond_resched(); /* We now go into synchronous reclaim */ cpuset_memory_pressure_bump(); fs_reclaim_acquire(gfp_mask); noreclaim_flag = memalloc_noreclaim_save(); progress = try_to_free_pages(ac->zonelist, order, gfp_mask, ac->nodemask); memalloc_noreclaim_restore(noreclaim_flag); fs_reclaim_release(gfp_mask); cond_resched(); return progress; } /* The really slow allocator path where we enter direct reclaim */ static inline struct page * __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order, unsigned int alloc_flags, const struct alloc_context *ac, unsigned long *did_some_progress) { struct page *page = NULL; unsigned long pflags; bool drained = false; psi_memstall_enter(&pflags); *did_some_progress = __perform_reclaim(gfp_mask, order, ac); if (unlikely(!(*did_some_progress))) goto out; retry: page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); /* * If an allocation failed after direct reclaim, it could be because * pages are pinned on the per-cpu lists or in high alloc reserves. * Shrink them and try again */ if (!page && !drained) { unreserve_highatomic_pageblock(ac, false); drain_all_pages(NULL); drained = true; goto retry; } out: psi_memstall_leave(&pflags); return page; } static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask, const struct alloc_context *ac) { struct zoneref *z; struct zone *zone; pg_data_t *last_pgdat = NULL; enum zone_type highest_zoneidx = ac->highest_zoneidx; for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, highest_zoneidx, ac->nodemask) { if (!managed_zone(zone)) continue; if (last_pgdat != zone->zone_pgdat) { wakeup_kswapd(zone, gfp_mask, order, highest_zoneidx); last_pgdat = zone->zone_pgdat; } } } static inline unsigned int gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order) { unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET; /* * __GFP_HIGH is assumed to be the same as ALLOC_MIN_RESERVE * and __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD * to save two branches. */ BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_MIN_RESERVE); BUILD_BUG_ON(__GFP_KSWAPD_RECLAIM != (__force gfp_t) ALLOC_KSWAPD); /* * The caller may dip into page reserves a bit more if the caller * cannot run direct reclaim, or if the caller has realtime scheduling * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will * set both ALLOC_NON_BLOCK and ALLOC_MIN_RESERVE(__GFP_HIGH). */ alloc_flags |= (__force int) (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM)); if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) { /* * Not worth trying to allocate harder for __GFP_NOMEMALLOC even * if it can't schedule. */ if (!(gfp_mask & __GFP_NOMEMALLOC)) { alloc_flags |= ALLOC_NON_BLOCK; if (order > 0) alloc_flags |= ALLOC_HIGHATOMIC; } /* * Ignore cpuset mems for non-blocking __GFP_HIGH (probably * GFP_ATOMIC) rather than fail, see the comment for * cpuset_node_allowed(). */ if (alloc_flags & ALLOC_MIN_RESERVE) alloc_flags &= ~ALLOC_CPUSET; } else if (unlikely(rt_task(current)) && in_task()) alloc_flags |= ALLOC_MIN_RESERVE; alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags); return alloc_flags; } static bool oom_reserves_allowed(struct task_struct *tsk) { if (!tsk_is_oom_victim(tsk)) return false; /* * !MMU doesn't have oom reaper so give access to memory reserves * only to the thread with TIF_MEMDIE set */ if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE)) return false; return true; } /* * Distinguish requests which really need access to full memory * reserves from oom victims which can live with a portion of it */ static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask) { if (unlikely(gfp_mask & __GFP_NOMEMALLOC)) return 0; if (gfp_mask & __GFP_MEMALLOC) return ALLOC_NO_WATERMARKS; if (in_serving_softirq() && (current->flags & PF_MEMALLOC)) return ALLOC_NO_WATERMARKS; if (!in_interrupt()) { if (current->flags & PF_MEMALLOC) return ALLOC_NO_WATERMARKS; else if (oom_reserves_allowed(current)) return ALLOC_OOM; } return 0; } bool gfp_pfmemalloc_allowed(gfp_t gfp_mask) { return !!__gfp_pfmemalloc_flags(gfp_mask); } /* * Checks whether it makes sense to retry the reclaim to make a forward progress * for the given allocation request. * * We give up when we either have tried MAX_RECLAIM_RETRIES in a row * without success, or when we couldn't even meet the watermark if we * reclaimed all remaining pages on the LRU lists. * * Returns true if a retry is viable or false to enter the oom path. */ static inline bool should_reclaim_retry(gfp_t gfp_mask, unsigned order, struct alloc_context *ac, int alloc_flags, bool did_some_progress, int *no_progress_loops) { struct zone *zone; struct zoneref *z; bool ret = false; /* * Costly allocations might have made a progress but this doesn't mean * their order will become available due to high fragmentation so * always increment the no progress counter for them */ if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER) *no_progress_loops = 0; else (*no_progress_loops)++; if (*no_progress_loops > MAX_RECLAIM_RETRIES) goto out; /* * Keep reclaiming pages while there is a chance this will lead * somewhere. If none of the target zones can satisfy our allocation * request even if all reclaimable pages are considered then we are * screwed and have to go OOM. */ for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->highest_zoneidx, ac->nodemask) { unsigned long available; unsigned long reclaimable; unsigned long min_wmark = min_wmark_pages(zone); bool wmark; available = reclaimable = zone_reclaimable_pages(zone); available += zone_page_state_snapshot(zone, NR_FREE_PAGES); /* * Would the allocation succeed if we reclaimed all * reclaimable pages? */ wmark = __zone_watermark_ok(zone, order, min_wmark, ac->highest_zoneidx, alloc_flags, available); trace_reclaim_retry_zone(z, order, reclaimable, available, min_wmark, *no_progress_loops, wmark); if (wmark) { ret = true; break; } } /* * Memory allocation/reclaim might be called from a WQ context and the * current implementation of the WQ concurrency control doesn't * recognize that a particular WQ is congested if the worker thread is * looping without ever sleeping. Therefore we have to do a short sleep * here rather than calling cond_resched(). */ if (current->flags & PF_WQ_WORKER) schedule_timeout_uninterruptible(1); else cond_resched(); out: /* Before OOM, exhaust highatomic_reserve */ if (!ret) return unreserve_highatomic_pageblock(ac, true); return ret; } static inline bool check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac) { /* * It's possible that cpuset's mems_allowed and the nodemask from * mempolicy don't intersect. This should be normally dealt with by * policy_nodemask(), but it's possible to race with cpuset update in * such a way the check therein was true, and then it became false * before we got our cpuset_mems_cookie here. * This assumes that for all allocations, ac->nodemask can come only * from MPOL_BIND mempolicy (whose documented semantics is to be ignored * when it does not intersect with the cpuset restrictions) or the * caller can deal with a violated nodemask. */ if (cpusets_enabled() && ac->nodemask && !cpuset_nodemask_valid_mems_allowed(ac->nodemask)) { ac->nodemask = NULL; return true; } /* * When updating a task's mems_allowed or mempolicy nodemask, it is * possible to race with parallel threads in such a way that our * allocation can fail while the mask is being updated. If we are about * to fail, check if the cpuset changed during allocation and if so, * retry. */ if (read_mems_allowed_retry(cpuset_mems_cookie)) return true; return false; } static inline struct page * __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, struct alloc_context *ac) { bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM; bool can_compact = gfp_compaction_allowed(gfp_mask); const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER; struct page *page = NULL; unsigned int alloc_flags; unsigned long did_some_progress; enum compact_priority compact_priority; enum compact_result compact_result; int compaction_retries; int no_progress_loops; unsigned int cpuset_mems_cookie; unsigned int zonelist_iter_cookie; int reserve_flags; restart: compaction_retries = 0; no_progress_loops = 0; compact_priority = DEF_COMPACT_PRIORITY; cpuset_mems_cookie = read_mems_allowed_begin(); zonelist_iter_cookie = zonelist_iter_begin(); /* * The fast path uses conservative alloc_flags to succeed only until * kswapd needs to be woken up, and to avoid the cost of setting up * alloc_flags precisely. So we do that now. */ alloc_flags = gfp_to_alloc_flags(gfp_mask, order); /* * We need to recalculate the starting point for the zonelist iterator * because we might have used different nodemask in the fast path, or * there was a cpuset modification and we are retrying - otherwise we * could end up iterating over non-eligible zones endlessly. */ ac->preferred_zoneref = first_zones_zonelist(ac->zonelist, ac->highest_zoneidx, ac->nodemask); if (!ac->preferred_zoneref->zone) goto nopage; /* * Check for insane configurations where the cpuset doesn't contain * any suitable zone to satisfy the request - e.g. non-movable * GFP_HIGHUSER allocations from MOVABLE nodes only. */ if (cpusets_insane_config() && (gfp_mask & __GFP_HARDWALL)) { struct zoneref *z = first_zones_zonelist(ac->zonelist, ac->highest_zoneidx, &cpuset_current_mems_allowed); if (!z->zone) goto nopage; } if (alloc_flags & ALLOC_KSWAPD) wake_all_kswapds(order, gfp_mask, ac); /* * The adjusted alloc_flags might result in immediate success, so try * that first */ page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); if (page) goto got_pg; /* * For costly allocations, try direct compaction first, as it's likely * that we have enough base pages and don't need to reclaim. For non- * movable high-order allocations, do that as well, as compaction will * try prevent permanent fragmentation by migrating from blocks of the * same migratetype. * Don't try this for allocations that are allowed to ignore * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen. */ if (can_direct_reclaim && can_compact && (costly_order || (order > 0 && ac->migratetype != MIGRATE_MOVABLE)) && !gfp_pfmemalloc_allowed(gfp_mask)) { page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac, INIT_COMPACT_PRIORITY, &compact_result); if (page) goto got_pg; /* * Checks for costly allocations with __GFP_NORETRY, which * includes some THP page fault allocations */ if (costly_order && (gfp_mask & __GFP_NORETRY)) { /* * If allocating entire pageblock(s) and compaction * failed because all zones are below low watermarks * or is prohibited because it recently failed at this * order, fail immediately unless the allocator has * requested compaction and reclaim retry. * * Reclaim is * - potentially very expensive because zones are far * below their low watermarks or this is part of very * bursty high order allocations, * - not guaranteed to help because isolate_freepages() * may not iterate over freed pages as part of its * linear scan, and * - unlikely to make entire pageblocks free on its * own. */ if (compact_result == COMPACT_SKIPPED || compact_result == COMPACT_DEFERRED) goto nopage; /* * Looks like reclaim/compaction is worth trying, but * sync compaction could be very expensive, so keep * using async compaction. */ compact_priority = INIT_COMPACT_PRIORITY; } } retry: /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */ if (alloc_flags & ALLOC_KSWAPD) wake_all_kswapds(order, gfp_mask, ac); reserve_flags = __gfp_pfmemalloc_flags(gfp_mask); if (reserve_flags) alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags) | (alloc_flags & ALLOC_KSWAPD); /* * Reset the nodemask and zonelist iterators if memory policies can be * ignored. These allocations are high priority and system rather than * user oriented. */ if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) { ac->nodemask = NULL; ac->preferred_zoneref = first_zones_zonelist(ac->zonelist, ac->highest_zoneidx, ac->nodemask); } /* Attempt with potentially adjusted zonelist and alloc_flags */ page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); if (page) goto got_pg; /* Caller is not willing to reclaim, we can't balance anything */ if (!can_direct_reclaim) goto nopage; /* Avoid recursion of direct reclaim */ if (current->flags & PF_MEMALLOC) goto nopage; /* Try direct reclaim and then allocating */ page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac, &did_some_progress); if (page) goto got_pg; /* Try direct compaction and then allocating */ page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac, compact_priority, &compact_result); if (page) goto got_pg; /* Do not loop if specifically requested */ if (gfp_mask & __GFP_NORETRY) goto nopage; /* * Do not retry costly high order allocations unless they are * __GFP_RETRY_MAYFAIL and we can compact */ if (costly_order && (!can_compact || !(gfp_mask & __GFP_RETRY_MAYFAIL))) goto nopage; if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags, did_some_progress > 0, &no_progress_loops)) goto retry; /* * It doesn't make any sense to retry for the compaction if the order-0 * reclaim is not able to make any progress because the current * implementation of the compaction depends on the sufficient amount * of free memory (see __compaction_suitable) */ if (did_some_progress > 0 && can_compact && should_compact_retry(ac, order, alloc_flags, compact_result, &compact_priority, &compaction_retries)) goto retry; /* * Deal with possible cpuset update races or zonelist updates to avoid * a unnecessary OOM kill. */ if (check_retry_cpuset(cpuset_mems_cookie, ac) || check_retry_zonelist(zonelist_iter_cookie)) goto restart; /* Reclaim has failed us, start killing things */ page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress); if (page) goto got_pg; /* Avoid allocations with no watermarks from looping endlessly */ if (tsk_is_oom_victim(current) && (alloc_flags & ALLOC_OOM || (gfp_mask & __GFP_NOMEMALLOC))) goto nopage; /* Retry as long as the OOM killer is making progress */ if (did_some_progress) { no_progress_loops = 0; goto retry; } nopage: /* * Deal with possible cpuset update races or zonelist updates to avoid * a unnecessary OOM kill. */ if (check_retry_cpuset(cpuset_mems_cookie, ac) || check_retry_zonelist(zonelist_iter_cookie)) goto restart; /* * Make sure that __GFP_NOFAIL request doesn't leak out and make sure * we always retry */ if (gfp_mask & __GFP_NOFAIL) { /* * All existing users of the __GFP_NOFAIL are blockable, so warn * of any new users that actually require GFP_NOWAIT */ if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask)) goto fail; /* * PF_MEMALLOC request from this context is rather bizarre * because we cannot reclaim anything and only can loop waiting * for somebody to do a work for us */ WARN_ON_ONCE_GFP(current->flags & PF_MEMALLOC, gfp_mask); /* * non failing costly orders are a hard requirement which we * are not prepared for much so let's warn about these users * so that we can identify them and convert them to something * else. */ WARN_ON_ONCE_GFP(costly_order, gfp_mask); /* * Help non-failing allocations by giving some access to memory * reserves normally used for high priority non-blocking * allocations but do not use ALLOC_NO_WATERMARKS because this * could deplete whole memory reserves which would just make * the situation worse. */ page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_MIN_RESERVE, ac); if (page) goto got_pg; cond_resched(); goto retry; } fail: warn_alloc(gfp_mask, ac->nodemask, "page allocation failure: order:%u", order); got_pg: return page; } static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, int preferred_nid, nodemask_t *nodemask, struct alloc_context *ac, gfp_t *alloc_gfp, unsigned int *alloc_flags) { ac->highest_zoneidx = gfp_zone(gfp_mask); ac->zonelist = node_zonelist(preferred_nid, gfp_mask); ac->nodemask = nodemask; ac->migratetype = gfp_migratetype(gfp_mask); if (cpusets_enabled()) { *alloc_gfp |= __GFP_HARDWALL; /* * When we are in the interrupt context, it is irrelevant * to the current task context. It means that any node ok. */ if (in_task() && !ac->nodemask) ac->nodemask = &cpuset_current_mems_allowed; else *alloc_flags |= ALLOC_CPUSET; } might_alloc(gfp_mask); if (should_fail_alloc_page(gfp_mask, order)) return false; *alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, *alloc_flags); /* Dirty zone balancing only done in the fast path */ ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE); /* * The preferred zone is used for statistics but crucially it is * also used as the starting point for the zonelist iterator. It * may get reset for allocations that ignore memory policies. */ ac->preferred_zoneref = first_zones_zonelist(ac->zonelist, ac->highest_zoneidx, ac->nodemask); return true; } /* * __alloc_pages_bulk - Allocate a number of order-0 pages to a list or array * @gfp: GFP flags for the allocation * @preferred_nid: The preferred NUMA node ID to allocate from * @nodemask: Set of nodes to allocate from, may be NULL * @nr_pages: The number of pages desired on the list or array * @page_list: Optional list to store the allocated pages * @page_array: Optional array to store the pages * * This is a batched version of the page allocator that attempts to * allocate nr_pages quickly. Pages are added to page_list if page_list * is not NULL, otherwise it is assumed that the page_array is valid. * * For lists, nr_pages is the number of pages that should be allocated. * * For arrays, only NULL elements are populated with pages and nr_pages * is the maximum number of pages that will be stored in the array. * * Returns the number of pages on the list or array. */ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid, nodemask_t *nodemask, int nr_pages, struct list_head *page_list, struct page **page_array) { struct page *page; unsigned long __maybe_unused UP_flags; struct zone *zone; struct zoneref *z; struct per_cpu_pages *pcp; struct list_head *pcp_list; struct alloc_context ac; gfp_t alloc_gfp; unsigned int alloc_flags = ALLOC_WMARK_LOW; int nr_populated = 0, nr_account = 0; /* * Skip populated array elements to determine if any pages need * to be allocated before disabling IRQs. */ while (page_array && nr_populated < nr_pages && page_array[nr_populated]) nr_populated++; /* No pages requested? */ if (unlikely(nr_pages <= 0)) goto out; /* Already populated array? */ if (unlikely(page_array && nr_pages - nr_populated == 0)) goto out; /* Bulk allocator does not support memcg accounting. */ if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT)) goto failed; /* Use the single page allocator for one page. */ if (nr_pages - nr_populated == 1) goto failed; #ifdef CONFIG_PAGE_OWNER /* * PAGE_OWNER may recurse into the allocator to allocate space to * save the stack with pagesets.lock held. Releasing/reacquiring * removes much of the performance benefit of bulk allocation so * force the caller to allocate one page at a time as it'll have * similar performance to added complexity to the bulk allocator. */ if (static_branch_unlikely(&page_owner_inited)) goto failed; #endif /* May set ALLOC_NOFRAGMENT, fragmentation will return 1 page. */ gfp &= gfp_allowed_mask; alloc_gfp = gfp; if (!prepare_alloc_pages(gfp, 0, preferred_nid, nodemask, &ac, &alloc_gfp, &alloc_flags)) goto out; gfp = alloc_gfp; /* Find an allowed local zone that meets the low watermark. */ for_each_zone_zonelist_nodemask(zone, z, ac.zonelist, ac.highest_zoneidx, ac.nodemask) { unsigned long mark; if (cpusets_enabled() && (alloc_flags & ALLOC_CPUSET) && !__cpuset_zone_allowed(zone, gfp)) { continue; } if (nr_online_nodes > 1 && zone != ac.preferred_zoneref->zone && zone_to_nid(zone) != zone_to_nid(ac.preferred_zoneref->zone)) { goto failed; } mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK) + nr_pages; if (zone_watermark_fast(zone, 0, mark, zonelist_zone_idx(ac.preferred_zoneref), alloc_flags, gfp)) { break; } } /* * If there are no allowed local zones that meets the watermarks then * try to allocate a single page and reclaim if necessary. */ if (unlikely(!zone)) goto failed; /* spin_trylock may fail due to a parallel drain or IRQ reentrancy. */ pcp_trylock_prepare(UP_flags); pcp = pcp_spin_trylock(zone->per_cpu_pageset); if (!pcp) goto failed_irq; /* Attempt the batch allocation */ pcp_list = &pcp->lists[order_to_pindex(ac.migratetype, 0)]; while (nr_populated < nr_pages) { /* Skip existing pages */ if (page_array && page_array[nr_populated]) { nr_populated++; continue; } page = __rmqueue_pcplist(zone, 0, ac.migratetype, alloc_flags, pcp, pcp_list); if (unlikely(!page)) { /* Try and allocate at least one page */ if (!nr_account) { pcp_spin_unlock(pcp); goto failed_irq; } break; } nr_account++; prep_new_page(page, 0, gfp, 0); if (page_list) list_add(&page->lru, page_list); else page_array[nr_populated] = page; nr_populated++; } pcp_spin_unlock(pcp); pcp_trylock_finish(UP_flags); __count_zid_vm_events(PGALLOC, zone_idx(zone), nr_account); zone_statistics(ac.preferred_zoneref->zone, zone, nr_account); out: return nr_populated; failed_irq: pcp_trylock_finish(UP_flags); failed: page = __alloc_pages_noprof(gfp, 0, preferred_nid, nodemask); if (page) { if (page_list) list_add(&page->lru, page_list); else page_array[nr_populated] = page; nr_populated++; } goto out; } EXPORT_SYMBOL_GPL(alloc_pages_bulk_noprof); /* * This is the 'heart' of the zoned buddy allocator. */ struct page *__alloc_pages_noprof(gfp_t gfp, unsigned int order, int preferred_nid, nodemask_t *nodemask) { struct page *page; unsigned int alloc_flags = ALLOC_WMARK_LOW; gfp_t alloc_gfp; /* The gfp_t that was actually used for allocation */ struct alloc_context ac = { }; /* * There are several places where we assume that the order value is sane * so bail out early if the request is out of bound. */ if (WARN_ON_ONCE_GFP(order > MAX_PAGE_ORDER, gfp)) return NULL; gfp &= gfp_allowed_mask; /* * Apply scoped allocation constraints. This is mainly about GFP_NOFS * resp. GFP_NOIO which has to be inherited for all allocation requests * from a particular context which has been marked by * memalloc_no{fs,io}_{save,restore}. And PF_MEMALLOC_PIN which ensures * movable zones are not used during allocation. */ gfp = current_gfp_context(gfp); alloc_gfp = gfp; if (!prepare_alloc_pages(gfp, order, preferred_nid, nodemask, &ac, &alloc_gfp, &alloc_flags)) return NULL; /* * Forbid the first pass from falling back to types that fragment * memory until all local zones are considered. */ alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp); /* First allocation attempt */ page = get_page_from_freelist(alloc_gfp, order, alloc_flags, &ac); if (likely(page)) goto out; alloc_gfp = gfp; ac.spread_dirty_pages = false; /* * Restore the original nodemask if it was potentially replaced with * &cpuset_current_mems_allowed to optimize the fast-path attempt. */ ac.nodemask = nodemask; page = __alloc_pages_slowpath(alloc_gfp, order, &ac); out: if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT) && page && unlikely(__memcg_kmem_charge_page(page, gfp, order) != 0)) { __free_pages(page, order); page = NULL; } trace_mm_page_alloc(page, order, alloc_gfp, ac.migratetype); kmsan_alloc_page(page, order, alloc_gfp); return page; } EXPORT_SYMBOL(__alloc_pages_noprof); struct folio *__folio_alloc_noprof(gfp_t gfp, unsigned int order, int preferred_nid, nodemask_t *nodemask) { struct page *page = __alloc_pages_noprof(gfp | __GFP_COMP, order, preferred_nid, nodemask); return page_rmappable_folio(page); } EXPORT_SYMBOL(__folio_alloc_noprof); /* * Common helper functions. Never use with __GFP_HIGHMEM because the returned * address cannot represent highmem pages. Use alloc_pages and then kmap if * you need to access high mem. */ unsigned long get_free_pages_noprof(gfp_t gfp_mask, unsigned int order) { struct page *page; page = alloc_pages_noprof(gfp_mask & ~__GFP_HIGHMEM, order); if (!page) return 0; return (unsigned long) page_address(page); } EXPORT_SYMBOL(get_free_pages_noprof); unsigned long get_zeroed_page_noprof(gfp_t gfp_mask) { return get_free_pages_noprof(gfp_mask | __GFP_ZERO, 0); } EXPORT_SYMBOL(get_zeroed_page_noprof); /** * __free_pages - Free pages allocated with alloc_pages(). * @page: The page pointer returned from alloc_pages(). * @order: The order of the allocation. * * This function can free multi-page allocations that are not compound * pages. It does not check that the @order passed in matches that of * the allocation, so it is easy to leak memory. Freeing more memory * than was allocated will probably emit a warning. * * If the last reference to this page is speculative, it will be released * by put_page() which only frees the first page of a non-compound * allocation. To prevent the remaining pages from being leaked, we free * the subsequent pages here. If you want to use the page's reference * count to decide when to free the allocation, you should allocate a * compound page, and use put_page() instead of __free_pages(). * * Context: May be called in interrupt context or while holding a normal * spinlock, but not in NMI context or while holding a raw spinlock. */ void __free_pages(struct page *page, unsigned int order) { /* get PageHead before we drop reference */ int head = PageHead(page); struct alloc_tag *tag = pgalloc_tag_get(page); if (put_page_testzero(page)) free_unref_page(page, order); else if (!head) { pgalloc_tag_sub_pages(tag, (1 << order) - 1); while (order-- > 0) free_unref_page(page + (1 << order), order); } } EXPORT_SYMBOL(__free_pages); void free_pages(unsigned long addr, unsigned int order) { if (addr != 0) { VM_BUG_ON(!virt_addr_valid((void *)addr)); __free_pages(virt_to_page((void *)addr), order); } } EXPORT_SYMBOL(free_pages); /* * Page Fragment: * An arbitrary-length arbitrary-offset area of memory which resides * within a 0 or higher order page. Multiple fragments within that page * are individually refcounted, in the page's reference counter. * * The page_frag functions below provide a simple allocation framework for * page fragments. This is used by the network stack and network device * drivers to provide a backing region of memory for use as either an * sk_buff->head, or to be used in the "frags" portion of skb_shared_info. */ static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, gfp_t gfp_mask) { struct page *page = NULL; gfp_t gfp = gfp_mask; #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) gfp_mask = (gfp_mask & ~__GFP_DIRECT_RECLAIM) | __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC; page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, PAGE_FRAG_CACHE_MAX_ORDER); nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE; #endif if (unlikely(!page)) page = alloc_pages_node(NUMA_NO_NODE, gfp, 0); nc->va = page ? page_address(page) : NULL; return page; } void page_frag_cache_drain(struct page_frag_cache *nc) { if (!nc->va) return; __page_frag_cache_drain(virt_to_head_page(nc->va), nc->pagecnt_bias); nc->va = NULL; } EXPORT_SYMBOL(page_frag_cache_drain); void __page_frag_cache_drain(struct page *page, unsigned int count) { VM_BUG_ON_PAGE(page_ref_count(page) == 0, page); if (page_ref_sub_and_test(page, count)) free_unref_page(page, compound_order(page)); } EXPORT_SYMBOL(__page_frag_cache_drain); void *__page_frag_alloc_align(struct page_frag_cache *nc, unsigned int fragsz, gfp_t gfp_mask, unsigned int align_mask) { unsigned int size = PAGE_SIZE; struct page *page; int offset; if (unlikely(!nc->va)) { refill: page = __page_frag_cache_refill(nc, gfp_mask); if (!page) return NULL; #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) /* if size can vary use size else just use PAGE_SIZE */ size = nc->size; #endif /* Even if we own the page, we do not use atomic_set(). * This would break get_page_unless_zero() users. */ page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE); /* reset page count bias and offset to start of new frag */ nc->pfmemalloc = page_is_pfmemalloc(page); nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; nc->offset = size; } offset = nc->offset - fragsz; if (unlikely(offset < 0)) { page = virt_to_page(nc->va); if (!page_ref_sub_and_test(page, nc->pagecnt_bias)) goto refill; if (unlikely(nc->pfmemalloc)) { free_unref_page(page, compound_order(page)); goto refill; } #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) /* if size can vary use size else just use PAGE_SIZE */ size = nc->size; #endif /* OK, page count is 0, we can safely set it */ set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1); /* reset page count bias and offset to start of new frag */ nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; offset = size - fragsz; if (unlikely(offset < 0)) { /* * The caller is trying to allocate a fragment * with fragsz > PAGE_SIZE but the cache isn't big * enough to satisfy the request, this may * happen in low memory conditions. * We don't release the cache page because * it could make memory pressure worse * so we simply return NULL here. */ return NULL; } } nc->pagecnt_bias--; offset &= align_mask; nc->offset = offset; return nc->va + offset; } EXPORT_SYMBOL(__page_frag_alloc_align); /* * Frees a page fragment allocated out of either a compound or order 0 page. */ void page_frag_free(void *addr) { struct page *page = virt_to_head_page(addr); if (unlikely(put_page_testzero(page))) free_unref_page(page, compound_order(page)); } EXPORT_SYMBOL(page_frag_free); static void *make_alloc_exact(unsigned long addr, unsigned int order, size_t size) { if (addr) { unsigned long nr = DIV_ROUND_UP(size, PAGE_SIZE); struct page *page = virt_to_page((void *)addr); struct page *last = page + nr; split_page_owner(page, order, 0); pgalloc_tag_split(page, 1 << order); split_page_memcg(page, order, 0); while (page < --last) set_page_refcounted(last); last = page + (1UL << order); for (page += nr; page < last; page++) __free_pages_ok(page, 0, FPI_TO_TAIL); } return (void *)addr; } /** * alloc_pages_exact - allocate an exact number physically-contiguous pages. * @size: the number of bytes to allocate * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP * * This function is similar to alloc_pages(), except that it allocates the * minimum number of pages to satisfy the request. alloc_pages() can only * allocate memory in power-of-two pages. * * This function is also limited by MAX_PAGE_ORDER. * * Memory allocated by this function must be released by free_pages_exact(). * * Return: pointer to the allocated area or %NULL in case of error. */ void *alloc_pages_exact_noprof(size_t size, gfp_t gfp_mask) { unsigned int order = get_order(size); unsigned long addr; if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM))) gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM); addr = get_free_pages_noprof(gfp_mask, order); return make_alloc_exact(addr, order, size); } EXPORT_SYMBOL(alloc_pages_exact_noprof); /** * alloc_pages_exact_nid - allocate an exact number of physically-contiguous * pages on a node. * @nid: the preferred node ID where memory should be allocated * @size: the number of bytes to allocate * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP * * Like alloc_pages_exact(), but try to allocate on node nid first before falling * back. * * Return: pointer to the allocated area or %NULL in case of error. */ void * __meminit alloc_pages_exact_nid_noprof(int nid, size_t size, gfp_t gfp_mask) { unsigned int order = get_order(size); struct page *p; if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM))) gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM); p = alloc_pages_node_noprof(nid, gfp_mask, order); if (!p) return NULL; return make_alloc_exact((unsigned long)page_address(p), order, size); } /** * free_pages_exact - release memory allocated via alloc_pages_exact() * @virt: the value returned by alloc_pages_exact. * @size: size of allocation, same value as passed to alloc_pages_exact(). * * Release the memory allocated by a previous call to alloc_pages_exact. */ void free_pages_exact(void *virt, size_t size) { unsigned long addr = (unsigned long)virt; unsigned long end = addr + PAGE_ALIGN(size); while (addr < end) { free_page(addr); addr += PAGE_SIZE; } } EXPORT_SYMBOL(free_pages_exact); /** * nr_free_zone_pages - count number of pages beyond high watermark * @offset: The zone index of the highest zone * * nr_free_zone_pages() counts the number of pages which are beyond the * high watermark within all zones at or below a given zone index. For each * zone, the number of pages is calculated as: * * nr_free_zone_pages = managed_pages - high_pages * * Return: number of pages beyond high watermark. */ static unsigned long nr_free_zone_pages(int offset) { struct zoneref *z; struct zone *zone; /* Just pick one node, since fallback list is circular */ unsigned long sum = 0; struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL); for_each_zone_zonelist(zone, z, zonelist, offset) { unsigned long size = zone_managed_pages(zone); unsigned long high = high_wmark_pages(zone); if (size > high) sum += size - high; } return sum; } /** * nr_free_buffer_pages - count number of pages beyond high watermark * * nr_free_buffer_pages() counts the number of pages which are beyond the high * watermark within ZONE_DMA and ZONE_NORMAL. * * Return: number of pages beyond high watermark within ZONE_DMA and * ZONE_NORMAL. */ unsigned long nr_free_buffer_pages(void) { return nr_free_zone_pages(gfp_zone(GFP_USER)); } EXPORT_SYMBOL_GPL(nr_free_buffer_pages); static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref) { zoneref->zone = zone; zoneref->zone_idx = zone_idx(zone); } /* * Builds allocation fallback zone lists. * * Add all populated zones of a node to the zonelist. */ static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs) { struct zone *zone; enum zone_type zone_type = MAX_NR_ZONES; int nr_zones = 0; do { zone_type--; zone = pgdat->node_zones + zone_type; if (populated_zone(zone)) { zoneref_set_zone(zone, &zonerefs[nr_zones++]); check_highest_zone(zone_type); } } while (zone_type); return nr_zones; } #ifdef CONFIG_NUMA static int __parse_numa_zonelist_order(char *s) { /* * We used to support different zonelists modes but they turned * out to be just not useful. Let's keep the warning in place * if somebody still use the cmd line parameter so that we do * not fail it silently */ if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) { pr_warn("Ignoring unsupported numa_zonelist_order value: %s\n", s); return -EINVAL; } return 0; } static char numa_zonelist_order[] = "Node"; #define NUMA_ZONELIST_ORDER_LEN 16 /* * sysctl handler for numa_zonelist_order */ static int numa_zonelist_order_handler(const struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { if (write) return __parse_numa_zonelist_order(buffer); return proc_dostring(table, write, buffer, length, ppos); } static int node_load[MAX_NUMNODES]; /** * find_next_best_node - find the next node that should appear in a given node's fallback list * @node: node whose fallback list we're appending * @used_node_mask: nodemask_t of already used nodes * * We use a number of factors to determine which is the next node that should * appear on a given node's fallback list. The node should not have appeared * already in @node's fallback list, and it should be the next closest node * according to the distance array (which contains arbitrary distance values * from each node to each node in the system), and should also prefer nodes * with no CPUs, since presumably they'll have very little allocation pressure * on them otherwise. * * Return: node id of the found node or %NUMA_NO_NODE if no node is found. */ int find_next_best_node(int node, nodemask_t *used_node_mask) { int n, val; int min_val = INT_MAX; int best_node = NUMA_NO_NODE; /* * Use the local node if we haven't already, but for memoryless local * node, we should skip it and fall back to other nodes. */ if (!node_isset(node, *used_node_mask) && node_state(node, N_MEMORY)) { node_set(node, *used_node_mask); return node; } for_each_node_state(n, N_MEMORY) { /* Don't want a node to appear more than once */ if (node_isset(n, *used_node_mask)) continue; /* Use the distance array to find the distance */ val = node_distance(node, n); /* Penalize nodes under us ("prefer the next node") */ val += (n < node); /* Give preference to headless and unused nodes */ if (!cpumask_empty(cpumask_of_node(n))) val += PENALTY_FOR_NODE_WITH_CPUS; /* Slight preference for less loaded node */ val *= MAX_NUMNODES; val += node_load[n]; if (val < min_val) { min_val = val; best_node = n; } } if (best_node >= 0) node_set(best_node, *used_node_mask); return best_node; } /* * Build zonelists ordered by node and zones within node. * This results in maximum locality--normal zone overflows into local * DMA zone, if any--but risks exhausting DMA zone. */ static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order, unsigned nr_nodes) { struct zoneref *zonerefs; int i; zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; for (i = 0; i < nr_nodes; i++) { int nr_zones; pg_data_t *node = NODE_DATA(node_order[i]); nr_zones = build_zonerefs_node(node, zonerefs); zonerefs += nr_zones; } zonerefs->zone = NULL; zonerefs->zone_idx = 0; } /* * Build __GFP_THISNODE zonelists */ static void build_thisnode_zonelists(pg_data_t *pgdat) { struct zoneref *zonerefs; int nr_zones; zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs; nr_zones = build_zonerefs_node(pgdat, zonerefs); zonerefs += nr_zones; zonerefs->zone = NULL; zonerefs->zone_idx = 0; } /* * Build zonelists ordered by zone and nodes within zones. * This results in conserving DMA zone[s] until all Normal memory is * exhausted, but results in overflowing to remote node while memory * may still exist in local DMA zone. */ static void build_zonelists(pg_data_t *pgdat) { static int node_order[MAX_NUMNODES]; int node, nr_nodes = 0; nodemask_t used_mask = NODE_MASK_NONE; int local_node, prev_node; /* NUMA-aware ordering of nodes */ local_node = pgdat->node_id; prev_node = local_node; memset(node_order, 0, sizeof(node_order)); while ((node = find_next_best_node(local_node, &used_mask)) >= 0) { /* * We don't want to pressure a particular node. * So adding penalty to the first node in same * distance group to make it round-robin. */ if (node_distance(local_node, node) != node_distance(local_node, prev_node)) node_load[node] += 1; node_order[nr_nodes++] = node; prev_node = node; } build_zonelists_in_node_order(pgdat, node_order, nr_nodes); build_thisnode_zonelists(pgdat); pr_info("Fallback order for Node %d: ", local_node); for (node = 0; node < nr_nodes; node++) pr_cont("%d ", node_order[node]); pr_cont("\n"); } #ifdef CONFIG_HAVE_MEMORYLESS_NODES /* * Return node id of node used for "local" allocations. * I.e., first node id of first zone in arg node's generic zonelist. * Used for initializing percpu 'numa_mem', which is used primarily * for kernel allocations, so use GFP_KERNEL flags to locate zonelist. */ int local_memory_node(int node) { struct zoneref *z; z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL), gfp_zone(GFP_KERNEL), NULL); return zone_to_nid(z->zone); } #endif static void setup_min_unmapped_ratio(void); static void setup_min_slab_ratio(void); #else /* CONFIG_NUMA */ static void build_zonelists(pg_data_t *pgdat) { struct zoneref *zonerefs; int nr_zones; zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; nr_zones = build_zonerefs_node(pgdat, zonerefs); zonerefs += nr_zones; zonerefs->zone = NULL; zonerefs->zone_idx = 0; } #endif /* CONFIG_NUMA */ /* * Boot pageset table. One per cpu which is going to be used for all * zones and all nodes. The parameters will be set in such a way * that an item put on a list will immediately be handed over to * the buddy list. This is safe since pageset manipulation is done * with interrupts disabled. * * The boot_pagesets must be kept even after bootup is complete for * unused processors and/or zones. They do play a role for bootstrapping * hotplugged processors. * * zoneinfo_show() and maybe other functions do * not check if the processor is online before following the pageset pointer. * Other parts of the kernel may not check if the zone is available. */ static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonestat *pzstats); /* These effectively disable the pcplists in the boot pageset completely */ #define BOOT_PAGESET_HIGH 0 #define BOOT_PAGESET_BATCH 1 static DEFINE_PER_CPU(struct per_cpu_pages, boot_pageset); static DEFINE_PER_CPU(struct per_cpu_zonestat, boot_zonestats); static void __build_all_zonelists(void *data) { int nid; int __maybe_unused cpu; pg_data_t *self = data; unsigned long flags; /* * The zonelist_update_seq must be acquired with irqsave because the * reader can be invoked from IRQ with GFP_ATOMIC. */ write_seqlock_irqsave(&zonelist_update_seq, flags); /* * Also disable synchronous printk() to prevent any printk() from * trying to hold port->lock, for * tty_insert_flip_string_and_push_buffer() on other CPU might be * calling kmalloc(GFP_ATOMIC | __GFP_NOWARN) with port->lock held. */ printk_deferred_enter(); #ifdef CONFIG_NUMA memset(node_load, 0, sizeof(node_load)); #endif /* * This node is hotadded and no memory is yet present. So just * building zonelists is fine - no need to touch other nodes. */ if (self && !node_online(self->node_id)) { build_zonelists(self); } else { /* * All possible nodes have pgdat preallocated * in free_area_init */ for_each_node(nid) { pg_data_t *pgdat = NODE_DATA(nid); build_zonelists(pgdat); } #ifdef CONFIG_HAVE_MEMORYLESS_NODES /* * We now know the "local memory node" for each node-- * i.e., the node of the first zone in the generic zonelist. * Set up numa_mem percpu variable for on-line cpus. During * boot, only the boot cpu should be on-line; we'll init the * secondary cpus' numa_mem as they come on-line. During * node/memory hotplug, we'll fixup all on-line cpus. */ for_each_online_cpu(cpu) set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu))); #endif } printk_deferred_exit(); write_sequnlock_irqrestore(&zonelist_update_seq, flags); } static noinline void __init build_all_zonelists_init(void) { int cpu; __build_all_zonelists(NULL); /* * Initialize the boot_pagesets that are going to be used * for bootstrapping processors. The real pagesets for * each zone will be allocated later when the per cpu * allocator is available. * * boot_pagesets are used also for bootstrapping offline * cpus if the system is already booted because the pagesets * are needed to initialize allocators on a specific cpu too. * F.e. the percpu allocator needs the page allocator which * needs the percpu allocator in order to allocate its pagesets * (a chicken-egg dilemma). */ for_each_possible_cpu(cpu) per_cpu_pages_init(&per_cpu(boot_pageset, cpu), &per_cpu(boot_zonestats, cpu)); mminit_verify_zonelist(); cpuset_init_current_mems_allowed(); } /* * unless system_state == SYSTEM_BOOTING. * * __ref due to call of __init annotated helper build_all_zonelists_init * [protected by SYSTEM_BOOTING]. */ void __ref build_all_zonelists(pg_data_t *pgdat) { unsigned long vm_total_pages; if (system_state == SYSTEM_BOOTING) { build_all_zonelists_init(); } else { __build_all_zonelists(pgdat); /* cpuset refresh routine should be here */ } /* Get the number of free pages beyond high watermark in all zones. */ vm_total_pages = nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE)); /* * Disable grouping by mobility if the number of pages in the * system is too low to allow the mechanism to work. It would be * more accurate, but expensive to check per-zone. This check is * made on memory-hotadd so a system can start with mobility * disabled and enable it later */ if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES)) page_group_by_mobility_disabled = 1; else page_group_by_mobility_disabled = 0; pr_info("Built %u zonelists, mobility grouping %s. Total pages: %ld\n", nr_online_nodes, page_group_by_mobility_disabled ? "off" : "on", vm_total_pages); #ifdef CONFIG_NUMA pr_info("Policy zone: %s\n", zone_names[policy_zone]); #endif } static int zone_batchsize(struct zone *zone) { #ifdef CONFIG_MMU int batch; /* * The number of pages to batch allocate is either ~0.1% * of the zone or 1MB, whichever is smaller. The batch * size is striking a balance between allocation latency * and zone lock contention. */ batch = min(zone_managed_pages(zone) >> 10, SZ_1M / PAGE_SIZE); batch /= 4; /* We effectively *= 4 below */ if (batch < 1) batch = 1; /* * Clamp the batch to a 2^n - 1 value. Having a power * of 2 value was found to be more likely to have * suboptimal cache aliasing properties in some cases. * * For example if 2 tasks are alternately allocating * batches of pages, one task can end up with a lot * of pages of one half of the possible page colors * and the other with pages of the other colors. */ batch = rounddown_pow_of_two(batch + batch/2) - 1; return batch; #else /* The deferral and batching of frees should be suppressed under NOMMU * conditions. * * The problem is that NOMMU needs to be able to allocate large chunks * of contiguous memory as there's no hardware page translation to * assemble apparent contiguous memory from discontiguous pages. * * Queueing large contiguous runs of pages for batching, however, * causes the pages to actually be freed in smaller chunks. As there * can be a significant delay between the individual batches being * recycled, this leads to the once large chunks of space being * fragmented and becoming unavailable for high-order allocations. */ return 0; #endif } static int percpu_pagelist_high_fraction; static int zone_highsize(struct zone *zone, int batch, int cpu_online, int high_fraction) { #ifdef CONFIG_MMU int high; int nr_split_cpus; unsigned long total_pages; if (!high_fraction) { /* * By default, the high value of the pcp is based on the zone * low watermark so that if they are full then background * reclaim will not be started prematurely. */ total_pages = low_wmark_pages(zone); } else { /* * If percpu_pagelist_high_fraction is configured, the high * value is based on a fraction of the managed pages in the * zone. */ total_pages = zone_managed_pages(zone) / high_fraction; } /* * Split the high value across all online CPUs local to the zone. Note * that early in boot that CPUs may not be online yet and that during * CPU hotplug that the cpumask is not yet updated when a CPU is being * onlined. For memory nodes that have no CPUs, split the high value * across all online CPUs to mitigate the risk that reclaim is triggered * prematurely due to pages stored on pcp lists. */ nr_split_cpus = cpumask_weight(cpumask_of_node(zone_to_nid(zone))) + cpu_online; if (!nr_split_cpus) nr_split_cpus = num_online_cpus(); high = total_pages / nr_split_cpus; /* * Ensure high is at least batch*4. The multiple is based on the * historical relationship between high and batch. */ high = max(high, batch << 2); return high; #else return 0; #endif } /* * pcp->high and pcp->batch values are related and generally batch is lower * than high. They are also related to pcp->count such that count is lower * than high, and as soon as it reaches high, the pcplist is flushed. * * However, guaranteeing these relations at all times would require e.g. write * barriers here but also careful usage of read barriers at the read side, and * thus be prone to error and bad for performance. Thus the update only prevents * store tearing. Any new users of pcp->batch, pcp->high_min and pcp->high_max * should ensure they can cope with those fields changing asynchronously, and * fully trust only the pcp->count field on the local CPU with interrupts * disabled. * * mutex_is_locked(&pcp_batch_high_lock) required when calling this function * outside of boot time (or some other assurance that no concurrent updaters * exist). */ static void pageset_update(struct per_cpu_pages *pcp, unsigned long high_min, unsigned long high_max, unsigned long batch) { WRITE_ONCE(pcp->batch, batch); WRITE_ONCE(pcp->high_min, high_min); WRITE_ONCE(pcp->high_max, high_max); } static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonestat *pzstats) { int pindex; memset(pcp, 0, sizeof(*pcp)); memset(pzstats, 0, sizeof(*pzstats)); spin_lock_init(&pcp->lock); for (pindex = 0; pindex < NR_PCP_LISTS; pindex++) INIT_LIST_HEAD(&pcp->lists[pindex]); /* * Set batch and high values safe for a boot pageset. A true percpu * pageset's initialization will update them subsequently. Here we don't * need to be as careful as pageset_update() as nobody can access the * pageset yet. */ pcp->high_min = BOOT_PAGESET_HIGH; pcp->high_max = BOOT_PAGESET_HIGH; pcp->batch = BOOT_PAGESET_BATCH; pcp->free_count = 0; } static void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long high_min, unsigned long high_max, unsigned long batch) { struct per_cpu_pages *pcp; int cpu; for_each_possible_cpu(cpu) { pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); pageset_update(pcp, high_min, high_max, batch); } } /* * Calculate and set new high and batch values for all per-cpu pagesets of a * zone based on the zone's size. */ static void zone_set_pageset_high_and_batch(struct zone *zone, int cpu_online) { int new_high_min, new_high_max, new_batch; new_batch = max(1, zone_batchsize(zone)); if (percpu_pagelist_high_fraction) { new_high_min = zone_highsize(zone, new_batch, cpu_online, percpu_pagelist_high_fraction); /* * PCP high is tuned manually, disable auto-tuning via * setting high_min and high_max to the manual value. */ new_high_max = new_high_min; } else { new_high_min = zone_highsize(zone, new_batch, cpu_online, 0); new_high_max = zone_highsize(zone, new_batch, cpu_online, MIN_PERCPU_PAGELIST_HIGH_FRACTION); } if (zone->pageset_high_min == new_high_min && zone->pageset_high_max == new_high_max && zone->pageset_batch == new_batch) return; zone->pageset_high_min = new_high_min; zone->pageset_high_max = new_high_max; zone->pageset_batch = new_batch; __zone_set_pageset_high_and_batch(zone, new_high_min, new_high_max, new_batch); } void __meminit setup_zone_pageset(struct zone *zone) { int cpu; /* Size may be 0 on !SMP && !NUMA */ if (sizeof(struct per_cpu_zonestat) > 0) zone->per_cpu_zonestats = alloc_percpu(struct per_cpu_zonestat); zone->per_cpu_pageset = alloc_percpu(struct per_cpu_pages); for_each_possible_cpu(cpu) { struct per_cpu_pages *pcp; struct per_cpu_zonestat *pzstats; pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu); per_cpu_pages_init(pcp, pzstats); } zone_set_pageset_high_and_batch(zone, 0); } /* * The zone indicated has a new number of managed_pages; batch sizes and percpu * page high values need to be recalculated. */ static void zone_pcp_update(struct zone *zone, int cpu_online) { mutex_lock(&pcp_batch_high_lock); zone_set_pageset_high_and_batch(zone, cpu_online); mutex_unlock(&pcp_batch_high_lock); } static void zone_pcp_update_cacheinfo(struct zone *zone, unsigned int cpu) { struct per_cpu_pages *pcp; struct cpu_cacheinfo *cci; pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); cci = get_cpu_cacheinfo(cpu); /* * If data cache slice of CPU is large enough, "pcp->batch" * pages can be preserved in PCP before draining PCP for * consecutive high-order pages freeing without allocation. * This can reduce zone lock contention without hurting * cache-hot pages sharing. */ spin_lock(&pcp->lock); if ((cci->per_cpu_data_slice_size >> PAGE_SHIFT) > 3 * pcp->batch) pcp->flags |= PCPF_FREE_HIGH_BATCH; else pcp->flags &= ~PCPF_FREE_HIGH_BATCH; spin_unlock(&pcp->lock); } void setup_pcp_cacheinfo(unsigned int cpu) { struct zone *zone; for_each_populated_zone(zone) zone_pcp_update_cacheinfo(zone, cpu); } /* * Allocate per cpu pagesets and initialize them. * Before this call only boot pagesets were available. */ void __init setup_per_cpu_pageset(void) { struct pglist_data *pgdat; struct zone *zone; int __maybe_unused cpu; for_each_populated_zone(zone) setup_zone_pageset(zone); #ifdef CONFIG_NUMA /* * Unpopulated zones continue using the boot pagesets. * The numa stats for these pagesets need to be reset. * Otherwise, they will end up skewing the stats of * the nodes these zones are associated with. */ for_each_possible_cpu(cpu) { struct per_cpu_zonestat *pzstats = &per_cpu(boot_zonestats, cpu); memset(pzstats->vm_numa_event, 0, sizeof(pzstats->vm_numa_event)); } #endif for_each_online_pgdat(pgdat) pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat); } __meminit void zone_pcp_init(struct zone *zone) { /* * per cpu subsystem is not up at this point. The following code * relies on the ability of the linker to provide the * offset of a (static) per cpu variable into the per cpu area. */ zone->per_cpu_pageset = &boot_pageset; zone->per_cpu_zonestats = &boot_zonestats; zone->pageset_high_min = BOOT_PAGESET_HIGH; zone->pageset_high_max = BOOT_PAGESET_HIGH; zone->pageset_batch = BOOT_PAGESET_BATCH; if (populated_zone(zone)) pr_debug(" %s zone: %lu pages, LIFO batch:%u\n", zone->name, zone->present_pages, zone_batchsize(zone)); } void adjust_managed_page_count(struct page *page, long count) { atomic_long_add(count, &page_zone(page)->managed_pages); totalram_pages_add(count); } EXPORT_SYMBOL(adjust_managed_page_count); unsigned long free_reserved_area(void *start, void *end, int poison, const char *s) { void *pos; unsigned long pages = 0; start = (void *)PAGE_ALIGN((unsigned long)start); end = (void *)((unsigned long)end & PAGE_MASK); for (pos = start; pos < end; pos += PAGE_SIZE, pages++) { struct page *page = virt_to_page(pos); void *direct_map_addr; /* * 'direct_map_addr' might be different from 'pos' * because some architectures' virt_to_page() * work with aliases. Getting the direct map * address ensures that we get a _writeable_ * alias for the memset(). */ direct_map_addr = page_address(page); /* * Perform a kasan-unchecked memset() since this memory * has not been initialized. */ direct_map_addr = kasan_reset_tag(direct_map_addr); if ((unsigned int)poison <= 0xFF) memset(direct_map_addr, poison, PAGE_SIZE); free_reserved_page(page); } if (pages && s) pr_info("Freeing %s memory: %ldK\n", s, K(pages)); return pages; } void free_reserved_page(struct page *page) { clear_page_tag_ref(page); ClearPageReserved(page); init_page_count(page); __free_page(page); adjust_managed_page_count(page, 1); } EXPORT_SYMBOL(free_reserved_page); static int page_alloc_cpu_dead(unsigned int cpu) { struct zone *zone; lru_add_drain_cpu(cpu); mlock_drain_remote(cpu); drain_pages(cpu); /* * Spill the event counters of the dead processor * into the current processors event counters. * This artificially elevates the count of the current * processor. */ vm_events_fold_cpu(cpu); /* * Zero the differential counters of the dead processor * so that the vm statistics are consistent. * * This is only okay since the processor is dead and cannot * race with what we are doing. */ cpu_vm_stats_fold(cpu); for_each_populated_zone(zone) zone_pcp_update(zone, 0); return 0; } static int page_alloc_cpu_online(unsigned int cpu) { struct zone *zone; for_each_populated_zone(zone) zone_pcp_update(zone, 1); return 0; } void __init page_alloc_init_cpuhp(void) { int ret; ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC, "mm/page_alloc:pcp", page_alloc_cpu_online, page_alloc_cpu_dead); WARN_ON(ret < 0); } /* * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio * or min_free_kbytes changes. */ static void calculate_totalreserve_pages(void) { struct pglist_data *pgdat; unsigned long reserve_pages = 0; enum zone_type i, j; for_each_online_pgdat(pgdat) { pgdat->totalreserve_pages = 0; for (i = 0; i < MAX_NR_ZONES; i++) { struct zone *zone = pgdat->node_zones + i; long max = 0; unsigned long managed_pages = zone_managed_pages(zone); /* Find valid and maximum lowmem_reserve in the zone */ for (j = i; j < MAX_NR_ZONES; j++) { if (zone->lowmem_reserve[j] > max) max = zone->lowmem_reserve[j]; } /* we treat the high watermark as reserved pages. */ max += high_wmark_pages(zone); if (max > managed_pages) max = managed_pages; pgdat->totalreserve_pages += max; reserve_pages += max; } } totalreserve_pages = reserve_pages; } /* * setup_per_zone_lowmem_reserve - called whenever * sysctl_lowmem_reserve_ratio changes. Ensures that each zone * has a correct pages reserved value, so an adequate number of * pages are left in the zone after a successful __alloc_pages(). */ static void setup_per_zone_lowmem_reserve(void) { struct pglist_data *pgdat; enum zone_type i, j; for_each_online_pgdat(pgdat) { for (i = 0; i < MAX_NR_ZONES - 1; i++) { struct zone *zone = &pgdat->node_zones[i]; int ratio = sysctl_lowmem_reserve_ratio[i]; bool clear = !ratio || !zone_managed_pages(zone); unsigned long managed_pages = 0; for (j = i + 1; j < MAX_NR_ZONES; j++) { struct zone *upper_zone = &pgdat->node_zones[j]; bool empty = !zone_managed_pages(upper_zone); managed_pages += zone_managed_pages(upper_zone); if (clear || empty) zone->lowmem_reserve[j] = 0; else zone->lowmem_reserve[j] = managed_pages / ratio; } } } /* update totalreserve_pages */ calculate_totalreserve_pages(); } static void __setup_per_zone_wmarks(void) { unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10); unsigned long lowmem_pages = 0; struct zone *zone; unsigned long flags; /* Calculate total number of !ZONE_HIGHMEM and !ZONE_MOVABLE pages */ for_each_zone(zone) { if (!is_highmem(zone) && zone_idx(zone) != ZONE_MOVABLE) lowmem_pages += zone_managed_pages(zone); } for_each_zone(zone) { u64 tmp; spin_lock_irqsave(&zone->lock, flags); tmp = (u64)pages_min * zone_managed_pages(zone); tmp = div64_ul(tmp, lowmem_pages); if (is_highmem(zone) || zone_idx(zone) == ZONE_MOVABLE) { /* * __GFP_HIGH and PF_MEMALLOC allocations usually don't * need highmem and movable zones pages, so cap pages_min * to a small value here. * * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN) * deltas control async page reclaim, and so should * not be capped for highmem and movable zones. */ unsigned long min_pages; min_pages = zone_managed_pages(zone) / 1024; min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL); zone->_watermark[WMARK_MIN] = min_pages; } else { /* * If it's a lowmem zone, reserve a number of pages * proportionate to the zone's size. */ zone->_watermark[WMARK_MIN] = tmp; } /* * Set the kswapd watermarks distance according to the * scale factor in proportion to available memory, but * ensure a minimum size on small systems. */ tmp = max_t(u64, tmp >> 2, mult_frac(zone_managed_pages(zone), watermark_scale_factor, 10000)); zone->watermark_boost = 0; zone->_watermark[WMARK_LOW] = min_wmark_pages(zone) + tmp; zone->_watermark[WMARK_HIGH] = low_wmark_pages(zone) + tmp; zone->_watermark[WMARK_PROMO] = high_wmark_pages(zone) + tmp; spin_unlock_irqrestore(&zone->lock, flags); } /* update totalreserve_pages */ calculate_totalreserve_pages(); } /** * setup_per_zone_wmarks - called when min_free_kbytes changes * or when memory is hot-{added|removed} * * Ensures that the watermark[min,low,high] values for each zone are set * correctly with respect to min_free_kbytes. */ void setup_per_zone_wmarks(void) { struct zone *zone; static DEFINE_SPINLOCK(lock); spin_lock(&lock); __setup_per_zone_wmarks(); spin_unlock(&lock); /* * The watermark size have changed so update the pcpu batch * and high limits or the limits may be inappropriate. */ for_each_zone(zone) zone_pcp_update(zone, 0); } /* * Initialise min_free_kbytes. * * For small machines we want it small (128k min). For large machines * we want it large (256MB max). But it is not linear, because network * bandwidth does not increase linearly with machine size. We use * * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy: * min_free_kbytes = sqrt(lowmem_kbytes * 16) * * which yields * * 16MB: 512k * 32MB: 724k * 64MB: 1024k * 128MB: 1448k * 256MB: 2048k * 512MB: 2896k * 1024MB: 4096k * 2048MB: 5792k * 4096MB: 8192k * 8192MB: 11584k * 16384MB: 16384k */ void calculate_min_free_kbytes(void) { unsigned long lowmem_kbytes; int new_min_free_kbytes; lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10); new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16); if (new_min_free_kbytes > user_min_free_kbytes) min_free_kbytes = clamp(new_min_free_kbytes, 128, 262144); else pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n", new_min_free_kbytes, user_min_free_kbytes); } int __meminit init_per_zone_wmark_min(void) { calculate_min_free_kbytes(); setup_per_zone_wmarks(); refresh_zone_stat_thresholds(); setup_per_zone_lowmem_reserve(); #ifdef CONFIG_NUMA setup_min_unmapped_ratio(); setup_min_slab_ratio(); #endif khugepaged_min_free_kbytes_update(); return 0; } postcore_initcall(init_per_zone_wmark_min) /* * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so * that we can call two helper functions whenever min_free_kbytes * changes. */ static int min_free_kbytes_sysctl_handler(const struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { int rc; rc = proc_dointvec_minmax(table, write, buffer, length, ppos); if (rc) return rc; if (write) { user_min_free_kbytes = min_free_kbytes; setup_per_zone_wmarks(); } return 0; } static int watermark_scale_factor_sysctl_handler(const struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { int rc; rc = proc_dointvec_minmax(table, write, buffer, length, ppos); if (rc) return rc; if (write) setup_per_zone_wmarks(); return 0; } #ifdef CONFIG_NUMA static void setup_min_unmapped_ratio(void) { pg_data_t *pgdat; struct zone *zone; for_each_online_pgdat(pgdat) pgdat->min_unmapped_pages = 0; for_each_zone(zone) zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) * sysctl_min_unmapped_ratio) / 100; } static int sysctl_min_unmapped_ratio_sysctl_handler(const struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { int rc; rc = proc_dointvec_minmax(table, write, buffer, length, ppos); if (rc) return rc; setup_min_unmapped_ratio(); return 0; } static void setup_min_slab_ratio(void) { pg_data_t *pgdat; struct zone *zone; for_each_online_pgdat(pgdat) pgdat->min_slab_pages = 0; for_each_zone(zone) zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) * sysctl_min_slab_ratio) / 100; } static int sysctl_min_slab_ratio_sysctl_handler(const struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { int rc; rc = proc_dointvec_minmax(table, write, buffer, length, ppos); if (rc) return rc; setup_min_slab_ratio(); return 0; } #endif /* * lowmem_reserve_ratio_sysctl_handler - just a wrapper around * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve() * whenever sysctl_lowmem_reserve_ratio changes. * * The reserve ratio obviously has absolutely no relation with the * minimum watermarks. The lowmem reserve ratio can only make sense * if in function of the boot time zone sizes. */ static int lowmem_reserve_ratio_sysctl_handler(const struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { int i; proc_dointvec_minmax(table, write, buffer, length, ppos); for (i = 0; i < MAX_NR_ZONES; i++) { if (sysctl_lowmem_reserve_ratio[i] < 1) sysctl_lowmem_reserve_ratio[i] = 0; } setup_per_zone_lowmem_reserve(); return 0; } /* * percpu_pagelist_high_fraction - changes the pcp->high for each zone on each * cpu. It is the fraction of total pages in each zone that a hot per cpu * pagelist can have before it gets flushed back to buddy allocator. */ static int percpu_pagelist_high_fraction_sysctl_handler(const struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { struct zone *zone; int old_percpu_pagelist_high_fraction; int ret; mutex_lock(&pcp_batch_high_lock); old_percpu_pagelist_high_fraction = percpu_pagelist_high_fraction; ret = proc_dointvec_minmax(table, write, buffer, length, ppos); if (!write || ret < 0) goto out; /* Sanity checking to avoid pcp imbalance */ if (percpu_pagelist_high_fraction && percpu_pagelist_high_fraction < MIN_PERCPU_PAGELIST_HIGH_FRACTION) { percpu_pagelist_high_fraction = old_percpu_pagelist_high_fraction; ret = -EINVAL; goto out; } /* No change? */ if (percpu_pagelist_high_fraction == old_percpu_pagelist_high_fraction) goto out; for_each_populated_zone(zone) zone_set_pageset_high_and_batch(zone, 0); out: mutex_unlock(&pcp_batch_high_lock); return ret; } static struct ctl_table page_alloc_sysctl_table[] = { { .procname = "min_free_kbytes", .data = &min_free_kbytes, .maxlen = sizeof(min_free_kbytes), .mode = 0644, .proc_handler = min_free_kbytes_sysctl_handler, .extra1 = SYSCTL_ZERO, }, { .procname = "watermark_boost_factor", .data = &watermark_boost_factor, .maxlen = sizeof(watermark_boost_factor), .mode = 0644, .proc_handler = proc_dointvec_minmax, .extra1 = SYSCTL_ZERO, }, { .procname = "watermark_scale_factor", .data = &watermark_scale_factor, .maxlen = sizeof(watermark_scale_factor), .mode = 0644, .proc_handler = watermark_scale_factor_sysctl_handler, .extra1 = SYSCTL_ONE, .extra2 = SYSCTL_THREE_THOUSAND, }, { .procname = "percpu_pagelist_high_fraction", .data = &percpu_pagelist_high_fraction, .maxlen = sizeof(percpu_pagelist_high_fraction), .mode = 0644, .proc_handler = percpu_pagelist_high_fraction_sysctl_handler, .extra1 = SYSCTL_ZERO, }, { .procname = "lowmem_reserve_ratio", .data = &sysctl_lowmem_reserve_ratio, .maxlen = sizeof(sysctl_lowmem_reserve_ratio), .mode = 0644, .proc_handler = lowmem_reserve_ratio_sysctl_handler, }, #ifdef CONFIG_NUMA { .procname = "numa_zonelist_order", .data = &numa_zonelist_order, .maxlen = NUMA_ZONELIST_ORDER_LEN, .mode = 0644, .proc_handler = numa_zonelist_order_handler, }, { .procname = "min_unmapped_ratio", .data = &sysctl_min_unmapped_ratio, .maxlen = sizeof(sysctl_min_unmapped_ratio), .mode = 0644, .proc_handler = sysctl_min_unmapped_ratio_sysctl_handler, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE_HUNDRED, }, { .procname = "min_slab_ratio", .data = &sysctl_min_slab_ratio, .maxlen = sizeof(sysctl_min_slab_ratio), .mode = 0644, .proc_handler = sysctl_min_slab_ratio_sysctl_handler, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE_HUNDRED, }, #endif }; void __init page_alloc_sysctl_init(void) { register_sysctl_init("vm", page_alloc_sysctl_table); } #ifdef CONFIG_CONTIG_ALLOC /* Usage: See admin-guide/dynamic-debug-howto.rst */ static void alloc_contig_dump_pages(struct list_head *page_list) { DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, "migrate failure"); if (DYNAMIC_DEBUG_BRANCH(descriptor)) { struct page *page; dump_stack(); list_for_each_entry(page, page_list, lru) dump_page(page, "migration failure"); } } /* * [start, end) must belong to a single zone. * @migratetype: using migratetype to filter the type of migration in * trace_mm_alloc_contig_migrate_range_info. */ int __alloc_contig_migrate_range(struct compact_control *cc, unsigned long start, unsigned long end, int migratetype) { /* This function is based on compact_zone() from compaction.c. */ unsigned int nr_reclaimed; unsigned long pfn = start; unsigned int tries = 0; int ret = 0; struct migration_target_control mtc = { .nid = zone_to_nid(cc->zone), .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, .reason = MR_CONTIG_RANGE, }; struct page *page; unsigned long total_mapped = 0; unsigned long total_migrated = 0; unsigned long total_reclaimed = 0; lru_cache_disable(); while (pfn < end || !list_empty(&cc->migratepages)) { if (fatal_signal_pending(current)) { ret = -EINTR; break; } if (list_empty(&cc->migratepages)) { cc->nr_migratepages = 0; ret = isolate_migratepages_range(cc, pfn, end); if (ret && ret != -EAGAIN) break; pfn = cc->migrate_pfn; tries = 0; } else if (++tries == 5) { ret = -EBUSY; break; } nr_reclaimed = reclaim_clean_pages_from_list(cc->zone, &cc->migratepages); cc->nr_migratepages -= nr_reclaimed; if (trace_mm_alloc_contig_migrate_range_info_enabled()) { total_reclaimed += nr_reclaimed; list_for_each_entry(page, &cc->migratepages, lru) { struct folio *folio = page_folio(page); total_mapped += folio_mapped(folio) * folio_nr_pages(folio); } } ret = migrate_pages(&cc->migratepages, alloc_migration_target, NULL, (unsigned long)&mtc, cc->mode, MR_CONTIG_RANGE, NULL); if (trace_mm_alloc_contig_migrate_range_info_enabled() && !ret) total_migrated += cc->nr_migratepages; /* * On -ENOMEM, migrate_pages() bails out right away. It is pointless * to retry again over this error, so do the same here. */ if (ret == -ENOMEM) break; } lru_cache_enable(); if (ret < 0) { if (!(cc->gfp_mask & __GFP_NOWARN) && ret == -EBUSY) alloc_contig_dump_pages(&cc->migratepages); putback_movable_pages(&cc->migratepages); } trace_mm_alloc_contig_migrate_range_info(start, end, migratetype, total_migrated, total_reclaimed, total_mapped); return (ret < 0) ? ret : 0; } /** * alloc_contig_range() -- tries to allocate given range of pages * @start: start PFN to allocate * @end: one-past-the-last PFN to allocate * @migratetype: migratetype of the underlying pageblocks (either * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks * in range must have the same migratetype and it must * be either of the two. * @gfp_mask: GFP mask to use during compaction * * The PFN range does not have to be pageblock aligned. The PFN range must * belong to a single zone. * * The first thing this routine does is attempt to MIGRATE_ISOLATE all * pageblocks in the range. Once isolated, the pageblocks should not * be modified by others. * * Return: zero on success or negative error code. On success all * pages which PFN is in [start, end) are allocated for the caller and * need to be freed with free_contig_range(). */ int alloc_contig_range_noprof(unsigned long start, unsigned long end, unsigned migratetype, gfp_t gfp_mask) { unsigned long outer_start, outer_end; int ret = 0; struct compact_control cc = { .nr_migratepages = 0, .order = -1, .zone = page_zone(pfn_to_page(start)), .mode = MIGRATE_SYNC, .ignore_skip_hint = true, .no_set_skip_hint = true, .gfp_mask = current_gfp_context(gfp_mask), .alloc_contig = true, }; INIT_LIST_HEAD(&cc.migratepages); /* * What we do here is we mark all pageblocks in range as * MIGRATE_ISOLATE. Because pageblock and max order pages may * have different sizes, and due to the way page allocator * work, start_isolate_page_range() has special handlings for this. * * Once the pageblocks are marked as MIGRATE_ISOLATE, we * migrate the pages from an unaligned range (ie. pages that * we are interested in). This will put all the pages in * range back to page allocator as MIGRATE_ISOLATE. * * When this is done, we take the pages in range from page * allocator removing them from the buddy system. This way * page allocator will never consider using them. * * This lets us mark the pageblocks back as * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the * aligned range but not in the unaligned, original range are * put back to page allocator so that buddy can use them. */ ret = start_isolate_page_range(start, end, migratetype, 0, gfp_mask); if (ret) goto done; drain_all_pages(cc.zone); /* * In case of -EBUSY, we'd like to know which page causes problem. * So, just fall through. test_pages_isolated() has a tracepoint * which will report the busy page. * * It is possible that busy pages could become available before * the call to test_pages_isolated, and the range will actually be * allocated. So, if we fall through be sure to clear ret so that * -EBUSY is not accidentally used or returned to caller. */ ret = __alloc_contig_migrate_range(&cc, start, end, migratetype); if (ret && ret != -EBUSY) goto done; ret = 0; /* * Pages from [start, end) are within a pageblock_nr_pages * aligned blocks that are marked as MIGRATE_ISOLATE. What's * more, all pages in [start, end) are free in page allocator. * What we are going to do is to allocate all pages from * [start, end) (that is remove them from page allocator). * * The only problem is that pages at the beginning and at the * end of interesting range may be not aligned with pages that * page allocator holds, ie. they can be part of higher order * pages. Because of this, we reserve the bigger range and * once this is done free the pages we are not interested in. * * We don't have to hold zone->lock here because the pages are * isolated thus they won't get removed from buddy. */ outer_start = find_large_buddy(start); /* Make sure the range is really isolated. */ if (test_pages_isolated(outer_start, end, 0)) { ret = -EBUSY; goto done; } /* Grab isolated pages from freelists. */ outer_end = isolate_freepages_range(&cc, outer_start, end); if (!outer_end) { ret = -EBUSY; goto done; } /* Free head and tail (if any) */ if (start != outer_start) free_contig_range(outer_start, start - outer_start); if (end != outer_end) free_contig_range(end, outer_end - end); done: undo_isolate_page_range(start, end, migratetype); return ret; } EXPORT_SYMBOL(alloc_contig_range_noprof); static int __alloc_contig_pages(unsigned long start_pfn, unsigned long nr_pages, gfp_t gfp_mask) { unsigned long end_pfn = start_pfn + nr_pages; return alloc_contig_range_noprof(start_pfn, end_pfn, MIGRATE_MOVABLE, gfp_mask); } static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn, unsigned long nr_pages) { unsigned long i, end_pfn = start_pfn + nr_pages; struct page *page; for (i = start_pfn; i < end_pfn; i++) { page = pfn_to_online_page(i); if (!page) return false; if (page_zone(page) != z) return false; if (PageReserved(page)) return false; if (PageHuge(page)) return false; } return true; } static bool zone_spans_last_pfn(const struct zone *zone, unsigned long start_pfn, unsigned long nr_pages) { unsigned long last_pfn = start_pfn + nr_pages - 1; return zone_spans_pfn(zone, last_pfn); } /** * alloc_contig_pages() -- tries to find and allocate contiguous range of pages * @nr_pages: Number of contiguous pages to allocate * @gfp_mask: GFP mask to limit search and used during compaction * @nid: Target node * @nodemask: Mask for other possible nodes * * This routine is a wrapper around alloc_contig_range(). It scans over zones * on an applicable zonelist to find a contiguous pfn range which can then be * tried for allocation with alloc_contig_range(). This routine is intended * for allocation requests which can not be fulfilled with the buddy allocator. * * The allocated memory is always aligned to a page boundary. If nr_pages is a * power of two, then allocated range is also guaranteed to be aligned to same * nr_pages (e.g. 1GB request would be aligned to 1GB). * * Allocated pages can be freed with free_contig_range() or by manually calling * __free_page() on each allocated page. * * Return: pointer to contiguous pages on success, or NULL if not successful. */ struct page *alloc_contig_pages_noprof(unsigned long nr_pages, gfp_t gfp_mask, int nid, nodemask_t *nodemask) { unsigned long ret, pfn, flags; struct zonelist *zonelist; struct zone *zone; struct zoneref *z; zonelist = node_zonelist(nid, gfp_mask); for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nodemask) { spin_lock_irqsave(&zone->lock, flags); pfn = ALIGN(zone->zone_start_pfn, nr_pages); while (zone_spans_last_pfn(zone, pfn, nr_pages)) { if (pfn_range_valid_contig(zone, pfn, nr_pages)) { /* * We release the zone lock here because * alloc_contig_range() will also lock the zone * at some point. If there's an allocation * spinning on this lock, it may win the race * and cause alloc_contig_range() to fail... */ spin_unlock_irqrestore(&zone->lock, flags); ret = __alloc_contig_pages(pfn, nr_pages, gfp_mask); if (!ret) return pfn_to_page(pfn); spin_lock_irqsave(&zone->lock, flags); } pfn += nr_pages; } spin_unlock_irqrestore(&zone->lock, flags); } return NULL; } #endif /* CONFIG_CONTIG_ALLOC */ void free_contig_range(unsigned long pfn, unsigned long nr_pages) { unsigned long count = 0; for (; nr_pages--; pfn++) { struct page *page = pfn_to_page(pfn); count += page_count(page) != 1; __free_page(page); } WARN(count != 0, "%lu pages are still in use!\n", count); } EXPORT_SYMBOL(free_contig_range); /* * Effectively disable pcplists for the zone by setting the high limit to 0 * and draining all cpus. A concurrent page freeing on another CPU that's about * to put the page on pcplist will either finish before the drain and the page * will be drained, or observe the new high limit and skip the pcplist. * * Must be paired with a call to zone_pcp_enable(). */ void zone_pcp_disable(struct zone *zone) { mutex_lock(&pcp_batch_high_lock); __zone_set_pageset_high_and_batch(zone, 0, 0, 1); __drain_all_pages(zone, true); } void zone_pcp_enable(struct zone *zone) { __zone_set_pageset_high_and_batch(zone, zone->pageset_high_min, zone->pageset_high_max, zone->pageset_batch); mutex_unlock(&pcp_batch_high_lock); } void zone_pcp_reset(struct zone *zone) { int cpu; struct per_cpu_zonestat *pzstats; if (zone->per_cpu_pageset != &boot_pageset) { for_each_online_cpu(cpu) { pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu); drain_zonestat(zone, pzstats); } free_percpu(zone->per_cpu_pageset); zone->per_cpu_pageset = &boot_pageset; if (zone->per_cpu_zonestats != &boot_zonestats) { free_percpu(zone->per_cpu_zonestats); zone->per_cpu_zonestats = &boot_zonestats; } } } #ifdef CONFIG_MEMORY_HOTREMOVE /* * All pages in the range must be in a single zone, must not contain holes, * must span full sections, and must be isolated before calling this function. * * Returns the number of managed (non-PageOffline()) pages in the range: the * number of pages for which memory offlining code must adjust managed page * counters using adjust_managed_page_count(). */ unsigned long __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) { unsigned long already_offline = 0, flags; unsigned long pfn = start_pfn; struct page *page; struct zone *zone; unsigned int order; offline_mem_sections(pfn, end_pfn); zone = page_zone(pfn_to_page(pfn)); spin_lock_irqsave(&zone->lock, flags); while (pfn < end_pfn) { page = pfn_to_page(pfn); /* * The HWPoisoned page may be not in buddy system, and * page_count() is not 0. */ if (unlikely(!PageBuddy(page) && PageHWPoison(page))) { pfn++; continue; } /* * At this point all remaining PageOffline() pages have a * reference count of 0 and can simply be skipped. */ if (PageOffline(page)) { BUG_ON(page_count(page)); BUG_ON(PageBuddy(page)); already_offline++; pfn++; continue; } BUG_ON(page_count(page)); BUG_ON(!PageBuddy(page)); VM_WARN_ON(get_pageblock_migratetype(page) != MIGRATE_ISOLATE); order = buddy_order(page); del_page_from_free_list(page, zone, order, MIGRATE_ISOLATE); pfn += (1 << order); } spin_unlock_irqrestore(&zone->lock, flags); return end_pfn - start_pfn - already_offline; } #endif /* * This function returns a stable result only if called under zone lock. */ bool is_free_buddy_page(const struct page *page) { unsigned long pfn = page_to_pfn(page); unsigned int order; for (order = 0; order < NR_PAGE_ORDERS; order++) { const struct page *head = page - (pfn & ((1 << order) - 1)); if (PageBuddy(head) && buddy_order_unsafe(head) >= order) break; } return order <= MAX_PAGE_ORDER; } EXPORT_SYMBOL(is_free_buddy_page); #ifdef CONFIG_MEMORY_FAILURE static inline void add_to_free_list(struct page *page, struct zone *zone, unsigned int order, int migratetype, bool tail) { __add_to_free_list(page, zone, order, migratetype, tail); account_freepages(zone, 1 << order, migratetype); } /* * Break down a higher-order page in sub-pages, and keep our target out of * buddy allocator. */ static void break_down_buddy_pages(struct zone *zone, struct page *page, struct page *target, int low, int high, int migratetype) { unsigned long size = 1 << high; struct page *current_buddy; while (high > low) { high--; size >>= 1; if (target >= &page[size]) { current_buddy = page; page = page + size; } else { current_buddy = page + size; } if (set_page_guard(zone, current_buddy, high)) continue; add_to_free_list(current_buddy, zone, high, migratetype, false); set_buddy_order(current_buddy, high); } } /* * Take a page that will be marked as poisoned off the buddy allocator. */ bool take_page_off_buddy(struct page *page) { struct zone *zone = page_zone(page); unsigned long pfn = page_to_pfn(page); unsigned long flags; unsigned int order; bool ret = false; spin_lock_irqsave(&zone->lock, flags); for (order = 0; order < NR_PAGE_ORDERS; order++) { struct page *page_head = page - (pfn & ((1 << order) - 1)); int page_order = buddy_order(page_head); if (PageBuddy(page_head) && page_order >= order) { unsigned long pfn_head = page_to_pfn(page_head); int migratetype = get_pfnblock_migratetype(page_head, pfn_head); del_page_from_free_list(page_head, zone, page_order, migratetype); break_down_buddy_pages(zone, page_head, page, 0, page_order, migratetype); SetPageHWPoisonTakenOff(page); ret = true; break; } if (page_count(page_head) > 0) break; } spin_unlock_irqrestore(&zone->lock, flags); return ret; } /* * Cancel takeoff done by take_page_off_buddy(). */ bool put_page_back_buddy(struct page *page) { struct zone *zone = page_zone(page); unsigned long flags; bool ret = false; spin_lock_irqsave(&zone->lock, flags); if (put_page_testzero(page)) { unsigned long pfn = page_to_pfn(page); int migratetype = get_pfnblock_migratetype(page, pfn); ClearPageHWPoisonTakenOff(page); __free_one_page(page, pfn, zone, 0, migratetype, FPI_NONE); if (TestClearPageHWPoison(page)) { ret = true; } } spin_unlock_irqrestore(&zone->lock, flags); return ret; } #endif #ifdef CONFIG_ZONE_DMA bool has_managed_dma(void) { struct pglist_data *pgdat; for_each_online_pgdat(pgdat) { struct zone *zone = &pgdat->node_zones[ZONE_DMA]; if (managed_zone(zone)) return true; } return false; } #endif /* CONFIG_ZONE_DMA */ #ifdef CONFIG_UNACCEPTED_MEMORY /* Counts number of zones with unaccepted pages. */ static DEFINE_STATIC_KEY_FALSE(zones_with_unaccepted_pages); static bool lazy_accept = true; static int __init accept_memory_parse(char *p) { if (!strcmp(p, "lazy")) { lazy_accept = true; return 0; } else if (!strcmp(p, "eager")) { lazy_accept = false; return 0; } else { return -EINVAL; } } early_param("accept_memory", accept_memory_parse); static bool page_contains_unaccepted(struct page *page, unsigned int order) { phys_addr_t start = page_to_phys(page); phys_addr_t end = start + (PAGE_SIZE << order); return range_contains_unaccepted_memory(start, end); } static void accept_page(struct page *page, unsigned int order) { phys_addr_t start = page_to_phys(page); accept_memory(start, start + (PAGE_SIZE << order)); } static bool try_to_accept_memory_one(struct zone *zone) { unsigned long flags; struct page *page; bool last; spin_lock_irqsave(&zone->lock, flags); page = list_first_entry_or_null(&zone->unaccepted_pages, struct page, lru); if (!page) { spin_unlock_irqrestore(&zone->lock, flags); return false; } list_del(&page->lru); last = list_empty(&zone->unaccepted_pages); account_freepages(zone, -MAX_ORDER_NR_PAGES, MIGRATE_MOVABLE); __mod_zone_page_state(zone, NR_UNACCEPTED, -MAX_ORDER_NR_PAGES); spin_unlock_irqrestore(&zone->lock, flags); accept_page(page, MAX_PAGE_ORDER); __free_pages_ok(page, MAX_PAGE_ORDER, FPI_TO_TAIL); if (last) static_branch_dec(&zones_with_unaccepted_pages); return true; } static bool cond_accept_memory(struct zone *zone, unsigned int order) { long to_accept; bool ret = false; if (!has_unaccepted_memory()) return false; if (list_empty(&zone->unaccepted_pages)) return false; /* How much to accept to get to high watermark? */ to_accept = high_wmark_pages(zone) - (zone_page_state(zone, NR_FREE_PAGES) - __zone_watermark_unusable_free(zone, order, 0) - zone_page_state(zone, NR_UNACCEPTED)); while (to_accept > 0) { if (!try_to_accept_memory_one(zone)) break; ret = true; to_accept -= MAX_ORDER_NR_PAGES; } return ret; } static inline bool has_unaccepted_memory(void) { return static_branch_unlikely(&zones_with_unaccepted_pages); } static bool __free_unaccepted(struct page *page) { struct zone *zone = page_zone(page); unsigned long flags; bool first = false; if (!lazy_accept) return false; spin_lock_irqsave(&zone->lock, flags); first = list_empty(&zone->unaccepted_pages); list_add_tail(&page->lru, &zone->unaccepted_pages); account_freepages(zone, MAX_ORDER_NR_PAGES, MIGRATE_MOVABLE); __mod_zone_page_state(zone, NR_UNACCEPTED, MAX_ORDER_NR_PAGES); spin_unlock_irqrestore(&zone->lock, flags); if (first) static_branch_inc(&zones_with_unaccepted_pages); return true; } #else static bool page_contains_unaccepted(struct page *page, unsigned int order) { return false; } static void accept_page(struct page *page, unsigned int order) { } static bool cond_accept_memory(struct zone *zone, unsigned int order) { return false; } static inline bool has_unaccepted_memory(void) { return false; } static bool __free_unaccepted(struct page *page) { BUILD_BUG(); return false; } #endif /* CONFIG_UNACCEPTED_MEMORY */
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with Cregit http://github.com/cregit/cregit
Version 2.0-RC1