Contributors: 71
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Matthew Wilcox |
1083 |
29.43% |
53 |
22.94% |
| MinChan Kim |
379 |
10.30% |
10 |
4.33% |
| Ingo Molnar |
239 |
6.49% |
2 |
0.87% |
| Andrew Morton |
229 |
6.22% |
19 |
8.23% |
| Johannes Weiner |
226 |
6.14% |
13 |
5.63% |
| Yu Zhao |
178 |
4.84% |
7 |
3.03% |
| Shaohua Li |
156 |
4.24% |
4 |
1.73% |
| Shakeel Butt |
121 |
3.29% |
3 |
1.30% |
| Mel Gorman |
97 |
2.64% |
8 |
3.46% |
| Hugh Dickins |
94 |
2.55% |
10 |
4.33% |
| Chris Metcalf |
90 |
2.45% |
1 |
0.43% |
| yangge |
80 |
2.17% |
1 |
0.43% |
| Linus Torvalds (pre-git) |
76 |
2.07% |
13 |
5.63% |
| Alex Shi |
70 |
1.90% |
4 |
1.73% |
| Hisashi Hifumi |
67 |
1.82% |
1 |
0.43% |
| Michal Hocko |
36 |
0.98% |
4 |
1.73% |
| Adrian Bunk |
34 |
0.92% |
1 |
0.43% |
| Ahmed S. Darwish |
34 |
0.92% |
1 |
0.43% |
| Nicholas Piggin |
33 |
0.90% |
5 |
2.16% |
| Linus Torvalds |
32 |
0.87% |
7 |
3.03% |
| Miklos Szeredi |
24 |
0.65% |
3 |
1.30% |
| Konstantin Khlebnikov |
23 |
0.62% |
2 |
0.87% |
| Andrea Arcangeli |
21 |
0.57% |
3 |
1.30% |
| Alexander Zarochentzev |
21 |
0.57% |
1 |
0.43% |
| Kirill A. Shutemov |
21 |
0.57% |
2 |
0.87% |
| Jérôme Glisse |
20 |
0.54% |
1 |
0.43% |
| David Hildenbrand |
15 |
0.41% |
1 |
0.43% |
| Lee Schermerhorn |
14 |
0.38% |
2 |
0.87% |
| Fengguang Wu |
14 |
0.38% |
1 |
0.43% |
| Vladimir Davydov |
11 |
0.30% |
1 |
0.43% |
| Motohiro Kosaki |
10 |
0.27% |
2 |
0.87% |
| Ralph Campbell |
9 |
0.24% |
1 |
0.43% |
| Naoya Horiguchi |
7 |
0.19% |
1 |
0.43% |
| Kairui Song |
7 |
0.19% |
1 |
0.43% |
| Christoph Lameter |
7 |
0.19% |
3 |
1.30% |
| Steve French |
6 |
0.16% |
1 |
0.43% |
| Sebastian Andrzej Siewior |
6 |
0.16% |
1 |
0.43% |
| Ming Li |
6 |
0.16% |
1 |
0.43% |
| Rusty Russell |
5 |
0.14% |
2 |
0.87% |
| Roman Gushchin |
5 |
0.14% |
1 |
0.43% |
| Lorenzo Stoakes |
5 |
0.14% |
1 |
0.43% |
| Yang Shi |
4 |
0.11% |
1 |
0.43% |
| Vishal Moola (Oracle) |
4 |
0.11% |
1 |
0.43% |
| Kefeng Wang |
4 |
0.11% |
1 |
0.43% |
| Christoph Hellwig |
4 |
0.11% |
2 |
0.87% |
| Alexander Duyck |
4 |
0.11% |
1 |
0.43% |
| Marcelo Tosatti |
4 |
0.11% |
2 |
0.87% |
| Qian Cai |
4 |
0.11% |
1 |
0.43% |
| Arnaldo Carvalho de Melo |
4 |
0.11% |
1 |
0.43% |
| Dan J Williams |
3 |
0.08% |
1 |
0.43% |
| Balbir Singh |
3 |
0.08% |
1 |
0.43% |
| John Hubbard |
3 |
0.08% |
1 |
0.43% |
| Tejun Heo |
3 |
0.08% |
1 |
0.43% |
| Herbert Xu |
2 |
0.05% |
1 |
0.43% |
| Ira Weiny |
2 |
0.05% |
1 |
0.43% |
| David Howells |
2 |
0.05% |
1 |
0.43% |
| Rik Van Riel |
2 |
0.05% |
1 |
0.43% |
| David Rientjes |
2 |
0.05% |
1 |
0.43% |
| Robin Dong |
2 |
0.05% |
1 |
0.43% |
| Wang Sheng-Hui |
2 |
0.05% |
1 |
0.43% |
| JoonSoo Kim |
1 |
0.03% |
1 |
0.43% |
| Jianyu Zhan |
1 |
0.03% |
1 |
0.43% |
| Arun K S |
1 |
0.03% |
1 |
0.43% |
| Lukasz Odzioba |
1 |
0.03% |
1 |
0.43% |
| Mauro Carvalho Chehab |
1 |
0.03% |
1 |
0.43% |
| Paul Gortmaker |
1 |
0.03% |
1 |
0.43% |
| Bang Li |
1 |
0.03% |
1 |
0.43% |
| Sasha Levin |
1 |
0.03% |
1 |
0.43% |
| Miaohe Lin |
1 |
0.03% |
1 |
0.43% |
| Jan Beulich |
1 |
0.03% |
1 |
0.43% |
| Thomas Gleixner |
1 |
0.03% |
1 |
0.43% |
| Total |
3680 |
|
231 |
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/mm/swap.c
*
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*/
/*
* This file contains the default values for the operation of the
* Linux VM subsystem. Fine-tuning documentation can be found in
* Documentation/admin-guide/sysctl/vm.rst.
* Started 18.12.91
* Swap aging added 23.2.95, Stephen Tweedie.
* Buffermem limits added 12.3.98, Rik van Riel.
*/
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <linux/swap.h>
#include <linux/mman.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/mm_inline.h>
#include <linux/percpu_counter.h>
#include <linux/memremap.h>
#include <linux/percpu.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/backing-dev.h>
#include <linux/memcontrol.h>
#include <linux/gfp.h>
#include <linux/uio.h>
#include <linux/hugetlb.h>
#include <linux/page_idle.h>
#include <linux/local_lock.h>
#include <linux/buffer_head.h>
#include "internal.h"
#define CREATE_TRACE_POINTS
#include <trace/events/pagemap.h>
/* How many pages do we try to swap or page in/out together? As a power of 2 */
int page_cluster;
const int page_cluster_max = 31;
/* Protecting only lru_rotate.fbatch which requires disabling interrupts */
struct lru_rotate {
local_lock_t lock;
struct folio_batch fbatch;
};
static DEFINE_PER_CPU(struct lru_rotate, lru_rotate) = {
.lock = INIT_LOCAL_LOCK(lock),
};
/*
* The following folio batches are grouped together because they are protected
* by disabling preemption (and interrupts remain enabled).
*/
struct cpu_fbatches {
local_lock_t lock;
struct folio_batch lru_add;
struct folio_batch lru_deactivate_file;
struct folio_batch lru_deactivate;
struct folio_batch lru_lazyfree;
#ifdef CONFIG_SMP
struct folio_batch activate;
#endif
};
static DEFINE_PER_CPU(struct cpu_fbatches, cpu_fbatches) = {
.lock = INIT_LOCAL_LOCK(lock),
};
static void __page_cache_release(struct folio *folio, struct lruvec **lruvecp,
unsigned long *flagsp)
{
if (folio_test_lru(folio)) {
folio_lruvec_relock_irqsave(folio, lruvecp, flagsp);
lruvec_del_folio(*lruvecp, folio);
__folio_clear_lru_flags(folio);
}
/*
* In rare cases, when truncation or holepunching raced with
* munlock after VM_LOCKED was cleared, Mlocked may still be
* found set here. This does not indicate a problem, unless
* "unevictable_pgs_cleared" appears worryingly large.
*/
if (unlikely(folio_test_mlocked(folio))) {
long nr_pages = folio_nr_pages(folio);
__folio_clear_mlocked(folio);
zone_stat_mod_folio(folio, NR_MLOCK, -nr_pages);
count_vm_events(UNEVICTABLE_PGCLEARED, nr_pages);
}
}
/*
* This path almost never happens for VM activity - pages are normally freed
* in batches. But it gets used by networking - and for compound pages.
*/
static void page_cache_release(struct folio *folio)
{
struct lruvec *lruvec = NULL;
unsigned long flags;
__page_cache_release(folio, &lruvec, &flags);
if (lruvec)
unlock_page_lruvec_irqrestore(lruvec, flags);
}
void __folio_put(struct folio *folio)
{
if (unlikely(folio_is_zone_device(folio))) {
free_zone_device_folio(folio);
return;
} else if (folio_test_hugetlb(folio)) {
free_huge_folio(folio);
return;
}
page_cache_release(folio);
folio_undo_large_rmappable(folio);
mem_cgroup_uncharge(folio);
free_unref_page(&folio->page, folio_order(folio));
}
EXPORT_SYMBOL(__folio_put);
/**
* put_pages_list() - release a list of pages
* @pages: list of pages threaded on page->lru
*
* Release a list of pages which are strung together on page.lru.
*/
void put_pages_list(struct list_head *pages)
{
struct folio_batch fbatch;
struct folio *folio, *next;
folio_batch_init(&fbatch);
list_for_each_entry_safe(folio, next, pages, lru) {
if (!folio_put_testzero(folio))
continue;
if (folio_test_hugetlb(folio)) {
free_huge_folio(folio);
continue;
}
/* LRU flag must be clear because it's passed using the lru */
if (folio_batch_add(&fbatch, folio) > 0)
continue;
free_unref_folios(&fbatch);
}
if (fbatch.nr)
free_unref_folios(&fbatch);
INIT_LIST_HEAD(pages);
}
EXPORT_SYMBOL(put_pages_list);
typedef void (*move_fn_t)(struct lruvec *lruvec, struct folio *folio);
static void lru_add_fn(struct lruvec *lruvec, struct folio *folio)
{
int was_unevictable = folio_test_clear_unevictable(folio);
long nr_pages = folio_nr_pages(folio);
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
/*
* Is an smp_mb__after_atomic() still required here, before
* folio_evictable() tests the mlocked flag, to rule out the possibility
* of stranding an evictable folio on an unevictable LRU? I think
* not, because __munlock_folio() only clears the mlocked flag
* while the LRU lock is held.
*
* (That is not true of __page_cache_release(), and not necessarily
* true of folios_put(): but those only clear the mlocked flag after
* folio_put_testzero() has excluded any other users of the folio.)
*/
if (folio_evictable(folio)) {
if (was_unevictable)
__count_vm_events(UNEVICTABLE_PGRESCUED, nr_pages);
} else {
folio_clear_active(folio);
folio_set_unevictable(folio);
/*
* folio->mlock_count = !!folio_test_mlocked(folio)?
* But that leaves __mlock_folio() in doubt whether another
* actor has already counted the mlock or not. Err on the
* safe side, underestimate, let page reclaim fix it, rather
* than leaving a page on the unevictable LRU indefinitely.
*/
folio->mlock_count = 0;
if (!was_unevictable)
__count_vm_events(UNEVICTABLE_PGCULLED, nr_pages);
}
lruvec_add_folio(lruvec, folio);
trace_mm_lru_insertion(folio);
}
static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn)
{
int i;
struct lruvec *lruvec = NULL;
unsigned long flags = 0;
for (i = 0; i < folio_batch_count(fbatch); i++) {
struct folio *folio = fbatch->folios[i];
folio_lruvec_relock_irqsave(folio, &lruvec, &flags);
move_fn(lruvec, folio);
folio_set_lru(folio);
}
if (lruvec)
unlock_page_lruvec_irqrestore(lruvec, flags);
folios_put(fbatch);
}
static void folio_batch_add_and_move(struct folio_batch *fbatch,
struct folio *folio, move_fn_t move_fn)
{
if (folio_batch_add(fbatch, folio) && !folio_test_large(folio) &&
!lru_cache_disabled())
return;
folio_batch_move_lru(fbatch, move_fn);
}
static void lru_move_tail_fn(struct lruvec *lruvec, struct folio *folio)
{
if (!folio_test_unevictable(folio)) {
lruvec_del_folio(lruvec, folio);
folio_clear_active(folio);
lruvec_add_folio_tail(lruvec, folio);
__count_vm_events(PGROTATED, folio_nr_pages(folio));
}
}
/*
* Writeback is about to end against a folio which has been marked for
* immediate reclaim. If it still appears to be reclaimable, move it
* to the tail of the inactive list.
*
* folio_rotate_reclaimable() must disable IRQs, to prevent nasty races.
*/
void folio_rotate_reclaimable(struct folio *folio)
{
if (!folio_test_locked(folio) && !folio_test_dirty(folio) &&
!folio_test_unevictable(folio)) {
struct folio_batch *fbatch;
unsigned long flags;
folio_get(folio);
if (!folio_test_clear_lru(folio)) {
folio_put(folio);
return;
}
local_lock_irqsave(&lru_rotate.lock, flags);
fbatch = this_cpu_ptr(&lru_rotate.fbatch);
folio_batch_add_and_move(fbatch, folio, lru_move_tail_fn);
local_unlock_irqrestore(&lru_rotate.lock, flags);
}
}
void lru_note_cost(struct lruvec *lruvec, bool file,
unsigned int nr_io, unsigned int nr_rotated)
{
unsigned long cost;
/*
* Reflect the relative cost of incurring IO and spending CPU
* time on rotations. This doesn't attempt to make a precise
* comparison, it just says: if reloads are about comparable
* between the LRU lists, or rotations are overwhelmingly
* different between them, adjust scan balance for CPU work.
*/
cost = nr_io * SWAP_CLUSTER_MAX + nr_rotated;
do {
unsigned long lrusize;
/*
* Hold lruvec->lru_lock is safe here, since
* 1) The pinned lruvec in reclaim, or
* 2) From a pre-LRU page during refault (which also holds the
* rcu lock, so would be safe even if the page was on the LRU
* and could move simultaneously to a new lruvec).
*/
spin_lock_irq(&lruvec->lru_lock);
/* Record cost event */
if (file)
lruvec->file_cost += cost;
else
lruvec->anon_cost += cost;
/*
* Decay previous events
*
* Because workloads change over time (and to avoid
* overflow) we keep these statistics as a floating
* average, which ends up weighing recent refaults
* more than old ones.
*/
lrusize = lruvec_page_state(lruvec, NR_INACTIVE_ANON) +
lruvec_page_state(lruvec, NR_ACTIVE_ANON) +
lruvec_page_state(lruvec, NR_INACTIVE_FILE) +
lruvec_page_state(lruvec, NR_ACTIVE_FILE);
if (lruvec->file_cost + lruvec->anon_cost > lrusize / 4) {
lruvec->file_cost /= 2;
lruvec->anon_cost /= 2;
}
spin_unlock_irq(&lruvec->lru_lock);
} while ((lruvec = parent_lruvec(lruvec)));
}
void lru_note_cost_refault(struct folio *folio)
{
lru_note_cost(folio_lruvec(folio), folio_is_file_lru(folio),
folio_nr_pages(folio), 0);
}
static void folio_activate_fn(struct lruvec *lruvec, struct folio *folio)
{
if (!folio_test_active(folio) && !folio_test_unevictable(folio)) {
long nr_pages = folio_nr_pages(folio);
lruvec_del_folio(lruvec, folio);
folio_set_active(folio);
lruvec_add_folio(lruvec, folio);
trace_mm_lru_activate(folio);
__count_vm_events(PGACTIVATE, nr_pages);
__count_memcg_events(lruvec_memcg(lruvec), PGACTIVATE,
nr_pages);
}
}
#ifdef CONFIG_SMP
static void folio_activate_drain(int cpu)
{
struct folio_batch *fbatch = &per_cpu(cpu_fbatches.activate, cpu);
if (folio_batch_count(fbatch))
folio_batch_move_lru(fbatch, folio_activate_fn);
}
void folio_activate(struct folio *folio)
{
if (!folio_test_active(folio) && !folio_test_unevictable(folio)) {
struct folio_batch *fbatch;
folio_get(folio);
if (!folio_test_clear_lru(folio)) {
folio_put(folio);
return;
}
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.activate);
folio_batch_add_and_move(fbatch, folio, folio_activate_fn);
local_unlock(&cpu_fbatches.lock);
}
}
#else
static inline void folio_activate_drain(int cpu)
{
}
void folio_activate(struct folio *folio)
{
struct lruvec *lruvec;
if (folio_test_clear_lru(folio)) {
lruvec = folio_lruvec_lock_irq(folio);
folio_activate_fn(lruvec, folio);
unlock_page_lruvec_irq(lruvec);
folio_set_lru(folio);
}
}
#endif
static void __lru_cache_activate_folio(struct folio *folio)
{
struct folio_batch *fbatch;
int i;
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.lru_add);
/*
* Search backwards on the optimistic assumption that the folio being
* activated has just been added to this batch. Note that only
* the local batch is examined as a !LRU folio could be in the
* process of being released, reclaimed, migrated or on a remote
* batch that is currently being drained. Furthermore, marking
* a remote batch's folio active potentially hits a race where
* a folio is marked active just after it is added to the inactive
* list causing accounting errors and BUG_ON checks to trigger.
*/
for (i = folio_batch_count(fbatch) - 1; i >= 0; i--) {
struct folio *batch_folio = fbatch->folios[i];
if (batch_folio == folio) {
folio_set_active(folio);
break;
}
}
local_unlock(&cpu_fbatches.lock);
}
#ifdef CONFIG_LRU_GEN
static void folio_inc_refs(struct folio *folio)
{
unsigned long new_flags, old_flags = READ_ONCE(folio->flags);
if (folio_test_unevictable(folio))
return;
if (!folio_test_referenced(folio)) {
folio_set_referenced(folio);
return;
}
if (!folio_test_workingset(folio)) {
folio_set_workingset(folio);
return;
}
/* see the comment on MAX_NR_TIERS */
do {
new_flags = old_flags & LRU_REFS_MASK;
if (new_flags == LRU_REFS_MASK)
break;
new_flags += BIT(LRU_REFS_PGOFF);
new_flags |= old_flags & ~LRU_REFS_MASK;
} while (!try_cmpxchg(&folio->flags, &old_flags, new_flags));
}
#else
static void folio_inc_refs(struct folio *folio)
{
}
#endif /* CONFIG_LRU_GEN */
/**
* folio_mark_accessed - Mark a folio as having seen activity.
* @folio: The folio to mark.
*
* This function will perform one of the following transitions:
*
* * inactive,unreferenced -> inactive,referenced
* * inactive,referenced -> active,unreferenced
* * active,unreferenced -> active,referenced
*
* When a newly allocated folio is not yet visible, so safe for non-atomic ops,
* __folio_set_referenced() may be substituted for folio_mark_accessed().
*/
void folio_mark_accessed(struct folio *folio)
{
if (lru_gen_enabled()) {
folio_inc_refs(folio);
return;
}
if (!folio_test_referenced(folio)) {
folio_set_referenced(folio);
} else if (folio_test_unevictable(folio)) {
/*
* Unevictable pages are on the "LRU_UNEVICTABLE" list. But,
* this list is never rotated or maintained, so marking an
* unevictable page accessed has no effect.
*/
} else if (!folio_test_active(folio)) {
/*
* If the folio is on the LRU, queue it for activation via
* cpu_fbatches.activate. Otherwise, assume the folio is in a
* folio_batch, mark it active and it'll be moved to the active
* LRU on the next drain.
*/
if (folio_test_lru(folio))
folio_activate(folio);
else
__lru_cache_activate_folio(folio);
folio_clear_referenced(folio);
workingset_activation(folio);
}
if (folio_test_idle(folio))
folio_clear_idle(folio);
}
EXPORT_SYMBOL(folio_mark_accessed);
/**
* folio_add_lru - Add a folio to an LRU list.
* @folio: The folio to be added to the LRU.
*
* Queue the folio for addition to the LRU. The decision on whether
* to add the page to the [in]active [file|anon] list is deferred until the
* folio_batch is drained. This gives a chance for the caller of folio_add_lru()
* have the folio added to the active list using folio_mark_accessed().
*/
void folio_add_lru(struct folio *folio)
{
struct folio_batch *fbatch;
VM_BUG_ON_FOLIO(folio_test_active(folio) &&
folio_test_unevictable(folio), folio);
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
/* see the comment in lru_gen_add_folio() */
if (lru_gen_enabled() && !folio_test_unevictable(folio) &&
lru_gen_in_fault() && !(current->flags & PF_MEMALLOC))
folio_set_active(folio);
folio_get(folio);
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.lru_add);
folio_batch_add_and_move(fbatch, folio, lru_add_fn);
local_unlock(&cpu_fbatches.lock);
}
EXPORT_SYMBOL(folio_add_lru);
/**
* folio_add_lru_vma() - Add a folio to the appropate LRU list for this VMA.
* @folio: The folio to be added to the LRU.
* @vma: VMA in which the folio is mapped.
*
* If the VMA is mlocked, @folio is added to the unevictable list.
* Otherwise, it is treated the same way as folio_add_lru().
*/
void folio_add_lru_vma(struct folio *folio, struct vm_area_struct *vma)
{
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
if (unlikely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) == VM_LOCKED))
mlock_new_folio(folio);
else
folio_add_lru(folio);
}
/*
* If the folio cannot be invalidated, it is moved to the
* inactive list to speed up its reclaim. It is moved to the
* head of the list, rather than the tail, to give the flusher
* threads some time to write it out, as this is much more
* effective than the single-page writeout from reclaim.
*
* If the folio isn't mapped and dirty/writeback, the folio
* could be reclaimed asap using the reclaim flag.
*
* 1. active, mapped folio -> none
* 2. active, dirty/writeback folio -> inactive, head, reclaim
* 3. inactive, mapped folio -> none
* 4. inactive, dirty/writeback folio -> inactive, head, reclaim
* 5. inactive, clean -> inactive, tail
* 6. Others -> none
*
* In 4, it moves to the head of the inactive list so the folio is
* written out by flusher threads as this is much more efficient
* than the single-page writeout from reclaim.
*/
static void lru_deactivate_file_fn(struct lruvec *lruvec, struct folio *folio)
{
bool active = folio_test_active(folio);
long nr_pages = folio_nr_pages(folio);
if (folio_test_unevictable(folio))
return;
/* Some processes are using the folio */
if (folio_mapped(folio))
return;
lruvec_del_folio(lruvec, folio);
folio_clear_active(folio);
folio_clear_referenced(folio);
if (folio_test_writeback(folio) || folio_test_dirty(folio)) {
/*
* Setting the reclaim flag could race with
* folio_end_writeback() and confuse readahead. But the
* race window is _really_ small and it's not a critical
* problem.
*/
lruvec_add_folio(lruvec, folio);
folio_set_reclaim(folio);
} else {
/*
* The folio's writeback ended while it was in the batch.
* We move that folio to the tail of the inactive list.
*/
lruvec_add_folio_tail(lruvec, folio);
__count_vm_events(PGROTATED, nr_pages);
}
if (active) {
__count_vm_events(PGDEACTIVATE, nr_pages);
__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
nr_pages);
}
}
static void lru_deactivate_fn(struct lruvec *lruvec, struct folio *folio)
{
if (!folio_test_unevictable(folio) && (folio_test_active(folio) || lru_gen_enabled())) {
long nr_pages = folio_nr_pages(folio);
lruvec_del_folio(lruvec, folio);
folio_clear_active(folio);
folio_clear_referenced(folio);
lruvec_add_folio(lruvec, folio);
__count_vm_events(PGDEACTIVATE, nr_pages);
__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
nr_pages);
}
}
static void lru_lazyfree_fn(struct lruvec *lruvec, struct folio *folio)
{
if (folio_test_anon(folio) && folio_test_swapbacked(folio) &&
!folio_test_swapcache(folio) && !folio_test_unevictable(folio)) {
long nr_pages = folio_nr_pages(folio);
lruvec_del_folio(lruvec, folio);
folio_clear_active(folio);
folio_clear_referenced(folio);
/*
* Lazyfree folios are clean anonymous folios. They have
* the swapbacked flag cleared, to distinguish them from normal
* anonymous folios
*/
folio_clear_swapbacked(folio);
lruvec_add_folio(lruvec, folio);
__count_vm_events(PGLAZYFREE, nr_pages);
__count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE,
nr_pages);
}
}
/*
* Drain pages out of the cpu's folio_batch.
* Either "cpu" is the current CPU, and preemption has already been
* disabled; or "cpu" is being hot-unplugged, and is already dead.
*/
void lru_add_drain_cpu(int cpu)
{
struct cpu_fbatches *fbatches = &per_cpu(cpu_fbatches, cpu);
struct folio_batch *fbatch = &fbatches->lru_add;
if (folio_batch_count(fbatch))
folio_batch_move_lru(fbatch, lru_add_fn);
fbatch = &per_cpu(lru_rotate.fbatch, cpu);
/* Disabling interrupts below acts as a compiler barrier. */
if (data_race(folio_batch_count(fbatch))) {
unsigned long flags;
/* No harm done if a racing interrupt already did this */
local_lock_irqsave(&lru_rotate.lock, flags);
folio_batch_move_lru(fbatch, lru_move_tail_fn);
local_unlock_irqrestore(&lru_rotate.lock, flags);
}
fbatch = &fbatches->lru_deactivate_file;
if (folio_batch_count(fbatch))
folio_batch_move_lru(fbatch, lru_deactivate_file_fn);
fbatch = &fbatches->lru_deactivate;
if (folio_batch_count(fbatch))
folio_batch_move_lru(fbatch, lru_deactivate_fn);
fbatch = &fbatches->lru_lazyfree;
if (folio_batch_count(fbatch))
folio_batch_move_lru(fbatch, lru_lazyfree_fn);
folio_activate_drain(cpu);
}
/**
* deactivate_file_folio() - Deactivate a file folio.
* @folio: Folio to deactivate.
*
* This function hints to the VM that @folio is a good reclaim candidate,
* for example if its invalidation fails due to the folio being dirty
* or under writeback.
*
* Context: Caller holds a reference on the folio.
*/
void deactivate_file_folio(struct folio *folio)
{
struct folio_batch *fbatch;
/* Deactivating an unevictable folio will not accelerate reclaim */
if (folio_test_unevictable(folio))
return;
folio_get(folio);
if (!folio_test_clear_lru(folio)) {
folio_put(folio);
return;
}
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.lru_deactivate_file);
folio_batch_add_and_move(fbatch, folio, lru_deactivate_file_fn);
local_unlock(&cpu_fbatches.lock);
}
/*
* folio_deactivate - deactivate a folio
* @folio: folio to deactivate
*
* folio_deactivate() moves @folio to the inactive list if @folio was on the
* active list and was not unevictable. This is done to accelerate the
* reclaim of @folio.
*/
void folio_deactivate(struct folio *folio)
{
if (!folio_test_unevictable(folio) && (folio_test_active(folio) ||
lru_gen_enabled())) {
struct folio_batch *fbatch;
folio_get(folio);
if (!folio_test_clear_lru(folio)) {
folio_put(folio);
return;
}
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.lru_deactivate);
folio_batch_add_and_move(fbatch, folio, lru_deactivate_fn);
local_unlock(&cpu_fbatches.lock);
}
}
/**
* folio_mark_lazyfree - make an anon folio lazyfree
* @folio: folio to deactivate
*
* folio_mark_lazyfree() moves @folio to the inactive file list.
* This is done to accelerate the reclaim of @folio.
*/
void folio_mark_lazyfree(struct folio *folio)
{
if (folio_test_anon(folio) && folio_test_swapbacked(folio) &&
!folio_test_swapcache(folio) && !folio_test_unevictable(folio)) {
struct folio_batch *fbatch;
folio_get(folio);
if (!folio_test_clear_lru(folio)) {
folio_put(folio);
return;
}
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.lru_lazyfree);
folio_batch_add_and_move(fbatch, folio, lru_lazyfree_fn);
local_unlock(&cpu_fbatches.lock);
}
}
void lru_add_drain(void)
{
local_lock(&cpu_fbatches.lock);
lru_add_drain_cpu(smp_processor_id());
local_unlock(&cpu_fbatches.lock);
mlock_drain_local();
}
/*
* It's called from per-cpu workqueue context in SMP case so
* lru_add_drain_cpu and invalidate_bh_lrus_cpu should run on
* the same cpu. It shouldn't be a problem in !SMP case since
* the core is only one and the locks will disable preemption.
*/
static void lru_add_and_bh_lrus_drain(void)
{
local_lock(&cpu_fbatches.lock);
lru_add_drain_cpu(smp_processor_id());
local_unlock(&cpu_fbatches.lock);
invalidate_bh_lrus_cpu();
mlock_drain_local();
}
void lru_add_drain_cpu_zone(struct zone *zone)
{
local_lock(&cpu_fbatches.lock);
lru_add_drain_cpu(smp_processor_id());
drain_local_pages(zone);
local_unlock(&cpu_fbatches.lock);
mlock_drain_local();
}
#ifdef CONFIG_SMP
static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
static void lru_add_drain_per_cpu(struct work_struct *dummy)
{
lru_add_and_bh_lrus_drain();
}
static bool cpu_needs_drain(unsigned int cpu)
{
struct cpu_fbatches *fbatches = &per_cpu(cpu_fbatches, cpu);
/* Check these in order of likelihood that they're not zero */
return folio_batch_count(&fbatches->lru_add) ||
data_race(folio_batch_count(&per_cpu(lru_rotate.fbatch, cpu))) ||
folio_batch_count(&fbatches->lru_deactivate_file) ||
folio_batch_count(&fbatches->lru_deactivate) ||
folio_batch_count(&fbatches->lru_lazyfree) ||
folio_batch_count(&fbatches->activate) ||
need_mlock_drain(cpu) ||
has_bh_in_lru(cpu, NULL);
}
/*
* Doesn't need any cpu hotplug locking because we do rely on per-cpu
* kworkers being shut down before our page_alloc_cpu_dead callback is
* executed on the offlined cpu.
* Calling this function with cpu hotplug locks held can actually lead
* to obscure indirect dependencies via WQ context.
*/
static inline void __lru_add_drain_all(bool force_all_cpus)
{
/*
* lru_drain_gen - Global pages generation number
*
* (A) Definition: global lru_drain_gen = x implies that all generations
* 0 < n <= x are already *scheduled* for draining.
*
* This is an optimization for the highly-contended use case where a
* user space workload keeps constantly generating a flow of pages for
* each CPU.
*/
static unsigned int lru_drain_gen;
static struct cpumask has_work;
static DEFINE_MUTEX(lock);
unsigned cpu, this_gen;
/*
* Make sure nobody triggers this path before mm_percpu_wq is fully
* initialized.
*/
if (WARN_ON(!mm_percpu_wq))
return;
/*
* Guarantee folio_batch counter stores visible by this CPU
* are visible to other CPUs before loading the current drain
* generation.
*/
smp_mb();
/*
* (B) Locally cache global LRU draining generation number
*
* The read barrier ensures that the counter is loaded before the mutex
* is taken. It pairs with smp_mb() inside the mutex critical section
* at (D).
*/
this_gen = smp_load_acquire(&lru_drain_gen);
mutex_lock(&lock);
/*
* (C) Exit the draining operation if a newer generation, from another
* lru_add_drain_all(), was already scheduled for draining. Check (A).
*/
if (unlikely(this_gen != lru_drain_gen && !force_all_cpus))
goto done;
/*
* (D) Increment global generation number
*
* Pairs with smp_load_acquire() at (B), outside of the critical
* section. Use a full memory barrier to guarantee that the
* new global drain generation number is stored before loading
* folio_batch counters.
*
* This pairing must be done here, before the for_each_online_cpu loop
* below which drains the page vectors.
*
* Let x, y, and z represent some system CPU numbers, where x < y < z.
* Assume CPU #z is in the middle of the for_each_online_cpu loop
* below and has already reached CPU #y's per-cpu data. CPU #x comes
* along, adds some pages to its per-cpu vectors, then calls
* lru_add_drain_all().
*
* If the paired barrier is done at any later step, e.g. after the
* loop, CPU #x will just exit at (C) and miss flushing out all of its
* added pages.
*/
WRITE_ONCE(lru_drain_gen, lru_drain_gen + 1);
smp_mb();
cpumask_clear(&has_work);
for_each_online_cpu(cpu) {
struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
if (cpu_needs_drain(cpu)) {
INIT_WORK(work, lru_add_drain_per_cpu);
queue_work_on(cpu, mm_percpu_wq, work);
__cpumask_set_cpu(cpu, &has_work);
}
}
for_each_cpu(cpu, &has_work)
flush_work(&per_cpu(lru_add_drain_work, cpu));
done:
mutex_unlock(&lock);
}
void lru_add_drain_all(void)
{
__lru_add_drain_all(false);
}
#else
void lru_add_drain_all(void)
{
lru_add_drain();
}
#endif /* CONFIG_SMP */
atomic_t lru_disable_count = ATOMIC_INIT(0);
/*
* lru_cache_disable() needs to be called before we start compiling
* a list of pages to be migrated using isolate_lru_page().
* It drains pages on LRU cache and then disable on all cpus until
* lru_cache_enable is called.
*
* Must be paired with a call to lru_cache_enable().
*/
void lru_cache_disable(void)
{
atomic_inc(&lru_disable_count);
/*
* Readers of lru_disable_count are protected by either disabling
* preemption or rcu_read_lock:
*
* preempt_disable, local_irq_disable [bh_lru_lock()]
* rcu_read_lock [rt_spin_lock CONFIG_PREEMPT_RT]
* preempt_disable [local_lock !CONFIG_PREEMPT_RT]
*
* Since v5.1 kernel, synchronize_rcu() is guaranteed to wait on
* preempt_disable() regions of code. So any CPU which sees
* lru_disable_count = 0 will have exited the critical
* section when synchronize_rcu() returns.
*/
synchronize_rcu_expedited();
#ifdef CONFIG_SMP
__lru_add_drain_all(true);
#else
lru_add_and_bh_lrus_drain();
#endif
}
/**
* folios_put_refs - Reduce the reference count on a batch of folios.
* @folios: The folios.
* @refs: The number of refs to subtract from each folio.
*
* Like folio_put(), but for a batch of folios. This is more efficient
* than writing the loop yourself as it will optimise the locks which need
* to be taken if the folios are freed. The folios batch is returned
* empty and ready to be reused for another batch; there is no need
* to reinitialise it. If @refs is NULL, we subtract one from each
* folio refcount.
*
* Context: May be called in process or interrupt context, but not in NMI
* context. May be called while holding a spinlock.
*/
void folios_put_refs(struct folio_batch *folios, unsigned int *refs)
{
int i, j;
struct lruvec *lruvec = NULL;
unsigned long flags = 0;
for (i = 0, j = 0; i < folios->nr; i++) {
struct folio *folio = folios->folios[i];
unsigned int nr_refs = refs ? refs[i] : 1;
if (is_huge_zero_folio(folio))
continue;
if (folio_is_zone_device(folio)) {
if (lruvec) {
unlock_page_lruvec_irqrestore(lruvec, flags);
lruvec = NULL;
}
if (put_devmap_managed_folio_refs(folio, nr_refs))
continue;
if (folio_ref_sub_and_test(folio, nr_refs))
free_zone_device_folio(folio);
continue;
}
if (!folio_ref_sub_and_test(folio, nr_refs))
continue;
/* hugetlb has its own memcg */
if (folio_test_hugetlb(folio)) {
if (lruvec) {
unlock_page_lruvec_irqrestore(lruvec, flags);
lruvec = NULL;
}
free_huge_folio(folio);
continue;
}
folio_undo_large_rmappable(folio);
__page_cache_release(folio, &lruvec, &flags);
if (j != i)
folios->folios[j] = folio;
j++;
}
if (lruvec)
unlock_page_lruvec_irqrestore(lruvec, flags);
if (!j) {
folio_batch_reinit(folios);
return;
}
folios->nr = j;
mem_cgroup_uncharge_folios(folios);
free_unref_folios(folios);
}
EXPORT_SYMBOL(folios_put_refs);
/**
* release_pages - batched put_page()
* @arg: array of pages to release
* @nr: number of pages
*
* Decrement the reference count on all the pages in @arg. If it
* fell to zero, remove the page from the LRU and free it.
*
* Note that the argument can be an array of pages, encoded pages,
* or folio pointers. We ignore any encoded bits, and turn any of
* them into just a folio that gets free'd.
*/
void release_pages(release_pages_arg arg, int nr)
{
struct folio_batch fbatch;
int refs[PAGEVEC_SIZE];
struct encoded_page **encoded = arg.encoded_pages;
int i;
folio_batch_init(&fbatch);
for (i = 0; i < nr; i++) {
/* Turn any of the argument types into a folio */
struct folio *folio = page_folio(encoded_page_ptr(encoded[i]));
/* Is our next entry actually "nr_pages" -> "nr_refs" ? */
refs[fbatch.nr] = 1;
if (unlikely(encoded_page_flags(encoded[i]) &
ENCODED_PAGE_BIT_NR_PAGES_NEXT))
refs[fbatch.nr] = encoded_nr_pages(encoded[++i]);
if (folio_batch_add(&fbatch, folio) > 0)
continue;
folios_put_refs(&fbatch, refs);
}
if (fbatch.nr)
folios_put_refs(&fbatch, refs);
}
EXPORT_SYMBOL(release_pages);
/*
* The folios which we're about to release may be in the deferred lru-addition
* queues. That would prevent them from really being freed right now. That's
* OK from a correctness point of view but is inefficient - those folios may be
* cache-warm and we want to give them back to the page allocator ASAP.
*
* So __folio_batch_release() will drain those queues here.
* folio_batch_move_lru() calls folios_put() directly to avoid
* mutual recursion.
*/
void __folio_batch_release(struct folio_batch *fbatch)
{
if (!fbatch->percpu_pvec_drained) {
lru_add_drain();
fbatch->percpu_pvec_drained = true;
}
folios_put(fbatch);
}
EXPORT_SYMBOL(__folio_batch_release);
/**
* folio_batch_remove_exceptionals() - Prune non-folios from a batch.
* @fbatch: The batch to prune
*
* find_get_entries() fills a batch with both folios and shadow/swap/DAX
* entries. This function prunes all the non-folio entries from @fbatch
* without leaving holes, so that it can be passed on to folio-only batch
* operations.
*/
void folio_batch_remove_exceptionals(struct folio_batch *fbatch)
{
unsigned int i, j;
for (i = 0, j = 0; i < folio_batch_count(fbatch); i++) {
struct folio *folio = fbatch->folios[i];
if (!xa_is_value(folio))
fbatch->folios[j++] = folio;
}
fbatch->nr = j;
}
/*
* Perform any setup for the swap system
*/
void __init swap_setup(void)
{
unsigned long megs = totalram_pages() >> (20 - PAGE_SHIFT);
/* Use a smaller cluster for small-memory machines */
if (megs < 16)
page_cluster = 2;
else
page_cluster = 3;
/*
* Right now other parts of the system means that we
* _really_ don't want to cluster much more
*/
}