| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Waiman Long | 7587 | 46.40% | 54 | 15.38% |
| Paul Jackson | 1897 | 11.60% | 21 | 5.98% |
| Tejun Heo | 1537 | 9.40% | 59 | 16.81% |
| Li Zefan | 1436 | 8.78% | 50 | 14.25% |
| Paul Menage | 1330 | 8.13% | 10 | 2.85% |
| Miao Xie | 271 | 1.66% | 9 | 2.56% |
| Juri Lelli | 261 | 1.60% | 9 | 2.56% |
| Dietmar Eggemann | 188 | 1.15% | 1 | 0.28% |
| Hidetoshi Seto | 185 | 1.13% | 1 | 0.28% |
| Mathieu J. Poirier | 151 | 0.92% | 2 | 0.57% |
| Will Deacon | 139 | 0.85% | 4 | 1.14% |
| Michal Koutný | 131 | 0.80% | 2 | 0.57% |
| Maksim Krasnyanskiy | 120 | 0.73% | 1 | 0.28% |
| Vladimir Davydov | 90 | 0.55% | 1 | 0.28% |
| Lai Jiangshan | 75 | 0.46% | 5 | 1.42% |
| Cliff Wickman | 65 | 0.40% | 2 | 0.57% |
| Feng Tang | 64 | 0.39% | 1 | 0.28% |
| Srivatsa S. Bhat | 63 | 0.39% | 2 | 0.57% |
| David Rientjes | 57 | 0.35% | 6 | 1.71% |
| Daniel Jordan | 57 | 0.35% | 1 | 0.28% |
| Mel Gorman | 49 | 0.30% | 3 | 0.85% |
| Ingo Molnar | 44 | 0.27% | 5 | 1.42% |
| Michal Hocko | 42 | 0.26% | 2 | 0.57% |
| Ben Blum | 37 | 0.23% | 2 | 0.57% |
| Jack Steiner | 36 | 0.22% | 1 | 0.28% |
| Andrew Morton | 31 | 0.19% | 6 | 1.71% |
| Eric W. Biedermann | 28 | 0.17% | 3 | 0.85% |
| Mike Travis | 27 | 0.17% | 2 | 0.57% |
| Peter Zijlstra | 25 | 0.15% | 5 | 1.42% |
| Frédéric Weisbecker | 21 | 0.13% | 4 | 1.14% |
| Rik Van Riel | 20 | 0.12% | 1 | 0.28% |
| Nicolas Saenz Julienne | 19 | 0.12% | 1 | 0.28% |
| Oleg Nesterov | 18 | 0.11% | 2 | 0.57% |
| Rusty Russell | 17 | 0.10% | 2 | 0.57% |
| Linus Torvalds (pre-git) | 16 | 0.10% | 9 | 2.56% |
| Sebastian Andrzej Siewior | 15 | 0.09% | 2 | 0.57% |
| Vlastimil Babka | 13 | 0.08% | 2 | 0.57% |
| Arnd Bergmann | 13 | 0.08% | 1 | 0.28% |
| Aditya Kali | 12 | 0.07% | 1 | 0.28% |
| Joonwoo Park | 12 | 0.07% | 1 | 0.28% |
| Srivatsa Vaddagiri | 10 | 0.06% | 2 | 0.57% |
| Nicholas Mc Guire | 9 | 0.06% | 1 | 0.28% |
| David P. Quigley | 9 | 0.06% | 1 | 0.28% |
| Harshit Mogalapalli | 8 | 0.05% | 1 | 0.28% |
| Gu Zheng | 8 | 0.05% | 1 | 0.28% |
| Valentin Schneider | 8 | 0.05% | 1 | 0.28% |
| Kees Cook | 7 | 0.04% | 2 | 0.57% |
| Dave Hansen | 7 | 0.04% | 2 | 0.57% |
| Christoph Lameter | 6 | 0.04% | 1 | 0.28% |
| Dima Zavin | 5 | 0.03% | 1 | 0.28% |
| Al Viro | 5 | 0.03% | 3 | 0.85% |
| Janak Desai | 4 | 0.02% | 1 | 0.28% |
| Liu Shixin | 4 | 0.02% | 2 | 0.57% |
| Bob Picco | 4 | 0.02% | 1 | 0.28% |
| Alexey Dobriyan | 3 | 0.02% | 1 | 0.28% |
| Fabian Frederick | 3 | 0.02% | 1 | 0.28% |
| Dario Faggioli | 3 | 0.02% | 1 | 0.28% |
| Randy Dunlap | 3 | 0.02% | 2 | 0.57% |
| Aristeu Sergio Rozanski Filho | 3 | 0.02% | 1 | 0.28% |
| yuzhoujian | 3 | 0.02% | 1 | 0.28% |
| Tom Rix | 3 | 0.02% | 1 | 0.28% |
| Yaowei Bai | 2 | 0.01% | 1 | 0.28% |
| Cai Xinchen | 2 | 0.01% | 1 | 0.28% |
| Joel Savitz | 2 | 0.01% | 1 | 0.28% |
| Zhang Qiao | 2 | 0.01% | 1 | 0.28% |
| Li Zhong | 2 | 0.01% | 1 | 0.28% |
| Miaohe Lin | 2 | 0.01% | 1 | 0.28% |
| Yinghai Lu | 2 | 0.01% | 1 | 0.28% |
| haifeng.xu | 2 | 0.01% | 1 | 0.28% |
| Kamalesh Babulal | 2 | 0.01% | 2 | 0.57% |
| Lu Jialin | 2 | 0.01% | 1 | 0.28% |
| Dmitry Adamushko | 2 | 0.01% | 1 | 0.28% |
| Linus Torvalds | 2 | 0.01% | 1 | 0.28% |
| Aubrey Li | 1 | 0.01% | 1 | 0.28% |
| Rasmus Villemoes | 1 | 0.01% | 1 | 0.28% |
| Keith Owens | 1 | 0.01% | 1 | 0.28% |
| Alban Crequy | 1 | 0.01% | 1 | 0.28% |
| David Howells | 1 | 0.01% | 1 | 0.28% |
| Wei Yongjun | 1 | 0.01% | 1 | 0.28% |
| Qi Zheng | 1 | 0.01% | 1 | 0.28% |
| Jiapeng Chong | 1 | 0.01% | 1 | 0.28% |
| Adrian Bunk | 1 | 0.01% | 1 | 0.28% |
| Dan Carpenter | 1 | 0.01% | 1 | 0.28% |
| Paul Gortmaker | 1 | 0.01% | 1 | 0.28% |
| Heiko Carstens | 1 | 0.01% | 1 | 0.28% |
| Xiongwei Song | 1 | 0.01% | 1 | 0.28% |
| Zhen Lei | 1 | 0.01% | 1 | 0.28% |
| Total | 16352 | 351 |
/* * kernel/cpuset.c * * Processor and Memory placement constraints for sets of tasks. * * Copyright (C) 2003 BULL SA. * Copyright (C) 2004-2007 Silicon Graphics, Inc. * Copyright (C) 2006 Google, Inc * * Portions derived from Patrick Mochel's sysfs code. * sysfs is Copyright (c) 2001-3 Patrick Mochel * * 2003-10-10 Written by Simon Derr. * 2003-10-22 Updates by Stephen Hemminger. * 2004 May-July Rework by Paul Jackson. * 2006 Rework by Paul Menage to use generic cgroups * 2008 Rework of the scheduler domains and CPU hotplug handling * by Max Krasnyansky * * This file is subject to the terms and conditions of the GNU General Public * License. See the file COPYING in the main directory of the Linux * distribution for more details. */ #include <linux/cpu.h> #include <linux/cpumask.h> #include <linux/cpuset.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/interrupt.h> #include <linux/kernel.h> #include <linux/mempolicy.h> #include <linux/mm.h> #include <linux/memory.h> #include <linux/export.h> #include <linux/rcupdate.h> #include <linux/sched.h> #include <linux/sched/deadline.h> #include <linux/sched/mm.h> #include <linux/sched/task.h> #include <linux/security.h> #include <linux/spinlock.h> #include <linux/oom.h> #include <linux/sched/isolation.h> #include <linux/cgroup.h> #include <linux/wait.h> #include <linux/workqueue.h> DEFINE_STATIC_KEY_FALSE(cpusets_pre_enable_key); DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key); /* * There could be abnormal cpuset configurations for cpu or memory * node binding, add this key to provide a quick low-cost judgment * of the situation. */ DEFINE_STATIC_KEY_FALSE(cpusets_insane_config_key); /* See "Frequency meter" comments, below. */ struct fmeter { int cnt; /* unprocessed events count */ int val; /* most recent output value */ time64_t time; /* clock (secs) when val computed */ spinlock_t lock; /* guards read or write of above */ }; /* * Invalid partition error code */ enum prs_errcode { PERR_NONE = 0, PERR_INVCPUS, PERR_INVPARENT, PERR_NOTPART, PERR_NOTEXCL, PERR_NOCPUS, PERR_HOTPLUG, PERR_CPUSEMPTY, PERR_HKEEPING, }; static const char * const perr_strings[] = { [PERR_INVCPUS] = "Invalid cpu list in cpuset.cpus.exclusive", [PERR_INVPARENT] = "Parent is an invalid partition root", [PERR_NOTPART] = "Parent is not a partition root", [PERR_NOTEXCL] = "Cpu list in cpuset.cpus not exclusive", [PERR_NOCPUS] = "Parent unable to distribute cpu downstream", [PERR_HOTPLUG] = "No cpu available due to hotplug", [PERR_CPUSEMPTY] = "cpuset.cpus is empty", [PERR_HKEEPING] = "partition config conflicts with housekeeping setup", }; struct cpuset { struct cgroup_subsys_state css; unsigned long flags; /* "unsigned long" so bitops work */ /* * On default hierarchy: * * The user-configured masks can only be changed by writing to * cpuset.cpus and cpuset.mems, and won't be limited by the * parent masks. * * The effective masks is the real masks that apply to the tasks * in the cpuset. They may be changed if the configured masks are * changed or hotplug happens. * * effective_mask == configured_mask & parent's effective_mask, * and if it ends up empty, it will inherit the parent's mask. * * * On legacy hierarchy: * * The user-configured masks are always the same with effective masks. */ /* user-configured CPUs and Memory Nodes allow to tasks */ cpumask_var_t cpus_allowed; nodemask_t mems_allowed; /* effective CPUs and Memory Nodes allow to tasks */ cpumask_var_t effective_cpus; nodemask_t effective_mems; /* * Exclusive CPUs dedicated to current cgroup (default hierarchy only) * * This exclusive CPUs must be a subset of cpus_allowed. A parent * cgroup can only grant exclusive CPUs to one of its children. * * When the cgroup becomes a valid partition root, effective_xcpus * defaults to cpus_allowed if not set. The effective_cpus of a valid * partition root comes solely from its effective_xcpus and some of the * effective_xcpus may be distributed to sub-partitions below & hence * excluded from its effective_cpus. */ cpumask_var_t effective_xcpus; /* * Exclusive CPUs as requested by the user (default hierarchy only) */ cpumask_var_t exclusive_cpus; /* * This is old Memory Nodes tasks took on. * * - top_cpuset.old_mems_allowed is initialized to mems_allowed. * - A new cpuset's old_mems_allowed is initialized when some * task is moved into it. * - old_mems_allowed is used in cpuset_migrate_mm() when we change * cpuset.mems_allowed and have tasks' nodemask updated, and * then old_mems_allowed is updated to mems_allowed. */ nodemask_t old_mems_allowed; struct fmeter fmeter; /* memory_pressure filter */ /* * Tasks are being attached to this cpuset. Used to prevent * zeroing cpus/mems_allowed between ->can_attach() and ->attach(). */ int attach_in_progress; /* partition number for rebuild_sched_domains() */ int pn; /* for custom sched domain */ int relax_domain_level; /* number of valid sub-partitions */ int nr_subparts; /* partition root state */ int partition_root_state; /* * Default hierarchy only: * use_parent_ecpus - set if using parent's effective_cpus * child_ecpus_count - # of children with use_parent_ecpus set */ int use_parent_ecpus; int child_ecpus_count; /* * number of SCHED_DEADLINE tasks attached to this cpuset, so that we * know when to rebuild associated root domain bandwidth information. */ int nr_deadline_tasks; int nr_migrate_dl_tasks; u64 sum_migrate_dl_bw; /* Invalid partition error code, not lock protected */ enum prs_errcode prs_err; /* Handle for cpuset.cpus.partition */ struct cgroup_file partition_file; /* Remote partition silbling list anchored at remote_children */ struct list_head remote_sibling; }; /* * Exclusive CPUs distributed out to sub-partitions of top_cpuset */ static cpumask_var_t subpartitions_cpus; /* * Exclusive CPUs in isolated partitions */ static cpumask_var_t isolated_cpus; /* List of remote partition root children */ static struct list_head remote_children; /* * Partition root states: * * 0 - member (not a partition root) * 1 - partition root * 2 - partition root without load balancing (isolated) * -1 - invalid partition root * -2 - invalid isolated partition root */ #define PRS_MEMBER 0 #define PRS_ROOT 1 #define PRS_ISOLATED 2 #define PRS_INVALID_ROOT -1 #define PRS_INVALID_ISOLATED -2 static inline bool is_prs_invalid(int prs_state) { return prs_state < 0; } /* * Temporary cpumasks for working with partitions that are passed among * functions to avoid memory allocation in inner functions. */ struct tmpmasks { cpumask_var_t addmask, delmask; /* For partition root */ cpumask_var_t new_cpus; /* For update_cpumasks_hier() */ }; static inline struct cpuset *css_cs(struct cgroup_subsys_state *css) { return css ? container_of(css, struct cpuset, css) : NULL; } /* Retrieve the cpuset for a task */ static inline struct cpuset *task_cs(struct task_struct *task) { return css_cs(task_css(task, cpuset_cgrp_id)); } static inline struct cpuset *parent_cs(struct cpuset *cs) { return css_cs(cs->css.parent); } void inc_dl_tasks_cs(struct task_struct *p) { struct cpuset *cs = task_cs(p); cs->nr_deadline_tasks++; } void dec_dl_tasks_cs(struct task_struct *p) { struct cpuset *cs = task_cs(p); cs->nr_deadline_tasks--; } /* bits in struct cpuset flags field */ typedef enum { CS_ONLINE, CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE, CS_MEM_HARDWALL, CS_MEMORY_MIGRATE, CS_SCHED_LOAD_BALANCE, CS_SPREAD_PAGE, CS_SPREAD_SLAB, } cpuset_flagbits_t; /* convenient tests for these bits */ static inline bool is_cpuset_online(struct cpuset *cs) { return test_bit(CS_ONLINE, &cs->flags) && !css_is_dying(&cs->css); } static inline int is_cpu_exclusive(const struct cpuset *cs) { return test_bit(CS_CPU_EXCLUSIVE, &cs->flags); } static inline int is_mem_exclusive(const struct cpuset *cs) { return test_bit(CS_MEM_EXCLUSIVE, &cs->flags); } static inline int is_mem_hardwall(const struct cpuset *cs) { return test_bit(CS_MEM_HARDWALL, &cs->flags); } static inline int is_sched_load_balance(const struct cpuset *cs) { return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); } static inline int is_memory_migrate(const struct cpuset *cs) { return test_bit(CS_MEMORY_MIGRATE, &cs->flags); } static inline int is_spread_page(const struct cpuset *cs) { return test_bit(CS_SPREAD_PAGE, &cs->flags); } static inline int is_spread_slab(const struct cpuset *cs) { return test_bit(CS_SPREAD_SLAB, &cs->flags); } static inline int is_partition_valid(const struct cpuset *cs) { return cs->partition_root_state > 0; } static inline int is_partition_invalid(const struct cpuset *cs) { return cs->partition_root_state < 0; } /* * Callers should hold callback_lock to modify partition_root_state. */ static inline void make_partition_invalid(struct cpuset *cs) { if (cs->partition_root_state > 0) cs->partition_root_state = -cs->partition_root_state; } /* * Send notification event of whenever partition_root_state changes. */ static inline void notify_partition_change(struct cpuset *cs, int old_prs) { if (old_prs == cs->partition_root_state) return; cgroup_file_notify(&cs->partition_file); /* Reset prs_err if not invalid */ if (is_partition_valid(cs)) WRITE_ONCE(cs->prs_err, PERR_NONE); } static struct cpuset top_cpuset = { .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)), .partition_root_state = PRS_ROOT, .remote_sibling = LIST_HEAD_INIT(top_cpuset.remote_sibling), }; /** * cpuset_for_each_child - traverse online children of a cpuset * @child_cs: loop cursor pointing to the current child * @pos_css: used for iteration * @parent_cs: target cpuset to walk children of * * Walk @child_cs through the online children of @parent_cs. Must be used * with RCU read locked. */ #define cpuset_for_each_child(child_cs, pos_css, parent_cs) \ css_for_each_child((pos_css), &(parent_cs)->css) \ if (is_cpuset_online(((child_cs) = css_cs((pos_css))))) /** * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants * @des_cs: loop cursor pointing to the current descendant * @pos_css: used for iteration * @root_cs: target cpuset to walk ancestor of * * Walk @des_cs through the online descendants of @root_cs. Must be used * with RCU read locked. The caller may modify @pos_css by calling * css_rightmost_descendant() to skip subtree. @root_cs is included in the * iteration and the first node to be visited. */ #define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs) \ css_for_each_descendant_pre((pos_css), &(root_cs)->css) \ if (is_cpuset_online(((des_cs) = css_cs((pos_css))))) /* * There are two global locks guarding cpuset structures - cpuset_mutex and * callback_lock. We also require taking task_lock() when dereferencing a * task's cpuset pointer. See "The task_lock() exception", at the end of this * comment. The cpuset code uses only cpuset_mutex. Other kernel subsystems * can use cpuset_lock()/cpuset_unlock() to prevent change to cpuset * structures. Note that cpuset_mutex needs to be a mutex as it is used in * paths that rely on priority inheritance (e.g. scheduler - on RT) for * correctness. * * A task must hold both locks to modify cpusets. If a task holds * cpuset_mutex, it blocks others, ensuring that it is the only task able to * also acquire callback_lock and be able to modify cpusets. It can perform * various checks on the cpuset structure first, knowing nothing will change. * It can also allocate memory while just holding cpuset_mutex. While it is * performing these checks, various callback routines can briefly acquire * callback_lock to query cpusets. Once it is ready to make the changes, it * takes callback_lock, blocking everyone else. * * Calls to the kernel memory allocator can not be made while holding * callback_lock, as that would risk double tripping on callback_lock * from one of the callbacks into the cpuset code from within * __alloc_pages(). * * If a task is only holding callback_lock, then it has read-only * access to cpusets. * * Now, the task_struct fields mems_allowed and mempolicy may be changed * by other task, we use alloc_lock in the task_struct fields to protect * them. * * The cpuset_common_file_read() handlers only hold callback_lock across * small pieces of code, such as when reading out possibly multi-word * cpumasks and nodemasks. * * Accessing a task's cpuset should be done in accordance with the * guidelines for accessing subsystem state in kernel/cgroup.c */ static DEFINE_MUTEX(cpuset_mutex); void cpuset_lock(void) { mutex_lock(&cpuset_mutex); } void cpuset_unlock(void) { mutex_unlock(&cpuset_mutex); } static DEFINE_SPINLOCK(callback_lock); static struct workqueue_struct *cpuset_migrate_mm_wq; /* * CPU / memory hotplug is handled asynchronously. */ static void cpuset_hotplug_workfn(struct work_struct *work); static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn); static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq); static inline void check_insane_mems_config(nodemask_t *nodes) { if (!cpusets_insane_config() && movable_only_nodes(nodes)) { static_branch_enable(&cpusets_insane_config_key); pr_info("Unsupported (movable nodes only) cpuset configuration detected (nmask=%*pbl)!\n" "Cpuset allocations might fail even with a lot of memory available.\n", nodemask_pr_args(nodes)); } } /* * Cgroup v2 behavior is used on the "cpus" and "mems" control files when * on default hierarchy or when the cpuset_v2_mode flag is set by mounting * the v1 cpuset cgroup filesystem with the "cpuset_v2_mode" mount option. * With v2 behavior, "cpus" and "mems" are always what the users have * requested and won't be changed by hotplug events. Only the effective * cpus or mems will be affected. */ static inline bool is_in_v2_mode(void) { return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || (cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE); } /** * partition_is_populated - check if partition has tasks * @cs: partition root to be checked * @excluded_child: a child cpuset to be excluded in task checking * Return: true if there are tasks, false otherwise * * It is assumed that @cs is a valid partition root. @excluded_child should * be non-NULL when this cpuset is going to become a partition itself. */ static inline bool partition_is_populated(struct cpuset *cs, struct cpuset *excluded_child) { struct cgroup_subsys_state *css; struct cpuset *child; if (cs->css.cgroup->nr_populated_csets) return true; if (!excluded_child && !cs->nr_subparts) return cgroup_is_populated(cs->css.cgroup); rcu_read_lock(); cpuset_for_each_child(child, css, cs) { if (child == excluded_child) continue; if (is_partition_valid(child)) continue; if (cgroup_is_populated(child->css.cgroup)) { rcu_read_unlock(); return true; } } rcu_read_unlock(); return false; } /* * Return in pmask the portion of a task's cpusets's cpus_allowed that * are online and are capable of running the task. If none are found, * walk up the cpuset hierarchy until we find one that does have some * appropriate cpus. * * One way or another, we guarantee to return some non-empty subset * of cpu_online_mask. * * Call with callback_lock or cpuset_mutex held. */ static void guarantee_online_cpus(struct task_struct *tsk, struct cpumask *pmask) { const struct cpumask *possible_mask = task_cpu_possible_mask(tsk); struct cpuset *cs; if (WARN_ON(!cpumask_and(pmask, possible_mask, cpu_online_mask))) cpumask_copy(pmask, cpu_online_mask); rcu_read_lock(); cs = task_cs(tsk); while (!cpumask_intersects(cs->effective_cpus, pmask)) { cs = parent_cs(cs); if (unlikely(!cs)) { /* * The top cpuset doesn't have any online cpu as a * consequence of a race between cpuset_hotplug_work * and cpu hotplug notifier. But we know the top * cpuset's effective_cpus is on its way to be * identical to cpu_online_mask. */ goto out_unlock; } } cpumask_and(pmask, pmask, cs->effective_cpus); out_unlock: rcu_read_unlock(); } /* * Return in *pmask the portion of a cpusets's mems_allowed that * are online, with memory. If none are online with memory, walk * up the cpuset hierarchy until we find one that does have some * online mems. The top cpuset always has some mems online. * * One way or another, we guarantee to return some non-empty subset * of node_states[N_MEMORY]. * * Call with callback_lock or cpuset_mutex held. */ static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask) { while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY])) cs = parent_cs(cs); nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]); } /* * update task's spread flag if cpuset's page/slab spread flag is set * * Call with callback_lock or cpuset_mutex held. The check can be skipped * if on default hierarchy. */ static void cpuset_update_task_spread_flags(struct cpuset *cs, struct task_struct *tsk) { if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) return; if (is_spread_page(cs)) task_set_spread_page(tsk); else task_clear_spread_page(tsk); if (is_spread_slab(cs)) task_set_spread_slab(tsk); else task_clear_spread_slab(tsk); } /* * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q? * * One cpuset is a subset of another if all its allowed CPUs and * Memory Nodes are a subset of the other, and its exclusive flags * are only set if the other's are set. Call holding cpuset_mutex. */ static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q) { return cpumask_subset(p->cpus_allowed, q->cpus_allowed) && nodes_subset(p->mems_allowed, q->mems_allowed) && is_cpu_exclusive(p) <= is_cpu_exclusive(q) && is_mem_exclusive(p) <= is_mem_exclusive(q); } /** * alloc_cpumasks - allocate three cpumasks for cpuset * @cs: the cpuset that have cpumasks to be allocated. * @tmp: the tmpmasks structure pointer * Return: 0 if successful, -ENOMEM otherwise. * * Only one of the two input arguments should be non-NULL. */ static inline int alloc_cpumasks(struct cpuset *cs, struct tmpmasks *tmp) { cpumask_var_t *pmask1, *pmask2, *pmask3, *pmask4; if (cs) { pmask1 = &cs->cpus_allowed; pmask2 = &cs->effective_cpus; pmask3 = &cs->effective_xcpus; pmask4 = &cs->exclusive_cpus; } else { pmask1 = &tmp->new_cpus; pmask2 = &tmp->addmask; pmask3 = &tmp->delmask; pmask4 = NULL; } if (!zalloc_cpumask_var(pmask1, GFP_KERNEL)) return -ENOMEM; if (!zalloc_cpumask_var(pmask2, GFP_KERNEL)) goto free_one; if (!zalloc_cpumask_var(pmask3, GFP_KERNEL)) goto free_two; if (pmask4 && !zalloc_cpumask_var(pmask4, GFP_KERNEL)) goto free_three; return 0; free_three: free_cpumask_var(*pmask3); free_two: free_cpumask_var(*pmask2); free_one: free_cpumask_var(*pmask1); return -ENOMEM; } /** * free_cpumasks - free cpumasks in a tmpmasks structure * @cs: the cpuset that have cpumasks to be free. * @tmp: the tmpmasks structure pointer */ static inline void free_cpumasks(struct cpuset *cs, struct tmpmasks *tmp) { if (cs) { free_cpumask_var(cs->cpus_allowed); free_cpumask_var(cs->effective_cpus); free_cpumask_var(cs->effective_xcpus); free_cpumask_var(cs->exclusive_cpus); } if (tmp) { free_cpumask_var(tmp->new_cpus); free_cpumask_var(tmp->addmask); free_cpumask_var(tmp->delmask); } } /** * alloc_trial_cpuset - allocate a trial cpuset * @cs: the cpuset that the trial cpuset duplicates */ static struct cpuset *alloc_trial_cpuset(struct cpuset *cs) { struct cpuset *trial; trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL); if (!trial) return NULL; if (alloc_cpumasks(trial, NULL)) { kfree(trial); return NULL; } cpumask_copy(trial->cpus_allowed, cs->cpus_allowed); cpumask_copy(trial->effective_cpus, cs->effective_cpus); cpumask_copy(trial->effective_xcpus, cs->effective_xcpus); cpumask_copy(trial->exclusive_cpus, cs->exclusive_cpus); return trial; } /** * free_cpuset - free the cpuset * @cs: the cpuset to be freed */ static inline void free_cpuset(struct cpuset *cs) { free_cpumasks(cs, NULL); kfree(cs); } static inline struct cpumask *fetch_xcpus(struct cpuset *cs) { return !cpumask_empty(cs->exclusive_cpus) ? cs->exclusive_cpus : cpumask_empty(cs->effective_xcpus) ? cs->cpus_allowed : cs->effective_xcpus; } /* * cpusets_are_exclusive() - check if two cpusets are exclusive * * Return true if exclusive, false if not */ static inline bool cpusets_are_exclusive(struct cpuset *cs1, struct cpuset *cs2) { struct cpumask *xcpus1 = fetch_xcpus(cs1); struct cpumask *xcpus2 = fetch_xcpus(cs2); if (cpumask_intersects(xcpus1, xcpus2)) return false; return true; } /* * validate_change_legacy() - Validate conditions specific to legacy (v1) * behavior. */ static int validate_change_legacy(struct cpuset *cur, struct cpuset *trial) { struct cgroup_subsys_state *css; struct cpuset *c, *par; int ret; WARN_ON_ONCE(!rcu_read_lock_held()); /* Each of our child cpusets must be a subset of us */ ret = -EBUSY; cpuset_for_each_child(c, css, cur) if (!is_cpuset_subset(c, trial)) goto out; /* On legacy hierarchy, we must be a subset of our parent cpuset. */ ret = -EACCES; par = parent_cs(cur); if (par && !is_cpuset_subset(trial, par)) goto out; ret = 0; out: return ret; } /* * validate_change() - Used to validate that any proposed cpuset change * follows the structural rules for cpusets. * * If we replaced the flag and mask values of the current cpuset * (cur) with those values in the trial cpuset (trial), would * our various subset and exclusive rules still be valid? Presumes * cpuset_mutex held. * * 'cur' is the address of an actual, in-use cpuset. Operations * such as list traversal that depend on the actual address of the * cpuset in the list must use cur below, not trial. * * 'trial' is the address of bulk structure copy of cur, with * perhaps one or more of the fields cpus_allowed, mems_allowed, * or flags changed to new, trial values. * * Return 0 if valid, -errno if not. */ static int validate_change(struct cpuset *cur, struct cpuset *trial) { struct cgroup_subsys_state *css; struct cpuset *c, *par; int ret = 0; rcu_read_lock(); if (!is_in_v2_mode()) ret = validate_change_legacy(cur, trial); if (ret) goto out; /* Remaining checks don't apply to root cpuset */ if (cur == &top_cpuset) goto out; par = parent_cs(cur); /* * Cpusets with tasks - existing or newly being attached - can't * be changed to have empty cpus_allowed or mems_allowed. */ ret = -ENOSPC; if ((cgroup_is_populated(cur->css.cgroup) || cur->attach_in_progress)) { if (!cpumask_empty(cur->cpus_allowed) && cpumask_empty(trial->cpus_allowed)) goto out; if (!nodes_empty(cur->mems_allowed) && nodes_empty(trial->mems_allowed)) goto out; } /* * We can't shrink if we won't have enough room for SCHED_DEADLINE * tasks. */ ret = -EBUSY; if (is_cpu_exclusive(cur) && !cpuset_cpumask_can_shrink(cur->cpus_allowed, trial->cpus_allowed)) goto out; /* * If either I or some sibling (!= me) is exclusive, we can't * overlap */ ret = -EINVAL; cpuset_for_each_child(c, css, par) { if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) && c != cur) { if (!cpusets_are_exclusive(trial, c)) goto out; } if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) && c != cur && nodes_intersects(trial->mems_allowed, c->mems_allowed)) goto out; } ret = 0; out: rcu_read_unlock(); return ret; } #ifdef CONFIG_SMP /* * Helper routine for generate_sched_domains(). * Do cpusets a, b have overlapping effective cpus_allowed masks? */ static int cpusets_overlap(struct cpuset *a, struct cpuset *b) { return cpumask_intersects(a->effective_cpus, b->effective_cpus); } static void update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c) { if (dattr->relax_domain_level < c->relax_domain_level) dattr->relax_domain_level = c->relax_domain_level; return; } static void update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *root_cs) { struct cpuset *cp; struct cgroup_subsys_state *pos_css; rcu_read_lock(); cpuset_for_each_descendant_pre(cp, pos_css, root_cs) { /* skip the whole subtree if @cp doesn't have any CPU */ if (cpumask_empty(cp->cpus_allowed)) { pos_css = css_rightmost_descendant(pos_css); continue; } if (is_sched_load_balance(cp)) update_domain_attr(dattr, cp); } rcu_read_unlock(); } /* Must be called with cpuset_mutex held. */ static inline int nr_cpusets(void) { /* jump label reference count + the top-level cpuset */ return static_key_count(&cpusets_enabled_key.key) + 1; } /* * generate_sched_domains() * * This function builds a partial partition of the systems CPUs * A 'partial partition' is a set of non-overlapping subsets whose * union is a subset of that set. * The output of this function needs to be passed to kernel/sched/core.c * partition_sched_domains() routine, which will rebuild the scheduler's * load balancing domains (sched domains) as specified by that partial * partition. * * See "What is sched_load_balance" in Documentation/admin-guide/cgroup-v1/cpusets.rst * for a background explanation of this. * * Does not return errors, on the theory that the callers of this * routine would rather not worry about failures to rebuild sched * domains when operating in the severe memory shortage situations * that could cause allocation failures below. * * Must be called with cpuset_mutex held. * * The three key local variables below are: * cp - cpuset pointer, used (together with pos_css) to perform a * top-down scan of all cpusets. For our purposes, rebuilding * the schedulers sched domains, we can ignore !is_sched_load_ * balance cpusets. * csa - (for CpuSet Array) Array of pointers to all the cpusets * that need to be load balanced, for convenient iterative * access by the subsequent code that finds the best partition, * i.e the set of domains (subsets) of CPUs such that the * cpus_allowed of every cpuset marked is_sched_load_balance * is a subset of one of these domains, while there are as * many such domains as possible, each as small as possible. * doms - Conversion of 'csa' to an array of cpumasks, for passing to * the kernel/sched/core.c routine partition_sched_domains() in a * convenient format, that can be easily compared to the prior * value to determine what partition elements (sched domains) * were changed (added or removed.) * * Finding the best partition (set of domains): * The triple nested loops below over i, j, k scan over the * load balanced cpusets (using the array of cpuset pointers in * csa[]) looking for pairs of cpusets that have overlapping * cpus_allowed, but which don't have the same 'pn' partition * number and gives them in the same partition number. It keeps * looping on the 'restart' label until it can no longer find * any such pairs. * * The union of the cpus_allowed masks from the set of * all cpusets having the same 'pn' value then form the one * element of the partition (one sched domain) to be passed to * partition_sched_domains(). */ static int generate_sched_domains(cpumask_var_t **domains, struct sched_domain_attr **attributes) { struct cpuset *cp; /* top-down scan of cpusets */ struct cpuset **csa; /* array of all cpuset ptrs */ int csn; /* how many cpuset ptrs in csa so far */ int i, j, k; /* indices for partition finding loops */ cpumask_var_t *doms; /* resulting partition; i.e. sched domains */ struct sched_domain_attr *dattr; /* attributes for custom domains */ int ndoms = 0; /* number of sched domains in result */ int nslot; /* next empty doms[] struct cpumask slot */ struct cgroup_subsys_state *pos_css; bool root_load_balance = is_sched_load_balance(&top_cpuset); doms = NULL; dattr = NULL; csa = NULL; /* Special case for the 99% of systems with one, full, sched domain */ if (root_load_balance && !top_cpuset.nr_subparts) { ndoms = 1; doms = alloc_sched_domains(ndoms); if (!doms) goto done; dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL); if (dattr) { *dattr = SD_ATTR_INIT; update_domain_attr_tree(dattr, &top_cpuset); } cpumask_and(doms[0], top_cpuset.effective_cpus, housekeeping_cpumask(HK_TYPE_DOMAIN)); goto done; } csa = kmalloc_array(nr_cpusets(), sizeof(cp), GFP_KERNEL); if (!csa) goto done; csn = 0; rcu_read_lock(); if (root_load_balance) csa[csn++] = &top_cpuset; cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) { if (cp == &top_cpuset) continue; /* * Continue traversing beyond @cp iff @cp has some CPUs and * isn't load balancing. The former is obvious. The * latter: All child cpusets contain a subset of the * parent's cpus, so just skip them, and then we call * update_domain_attr_tree() to calc relax_domain_level of * the corresponding sched domain. * * If root is load-balancing, we can skip @cp if it * is a subset of the root's effective_cpus. */ if (!cpumask_empty(cp->cpus_allowed) && !(is_sched_load_balance(cp) && cpumask_intersects(cp->cpus_allowed, housekeeping_cpumask(HK_TYPE_DOMAIN)))) continue; if (root_load_balance && cpumask_subset(cp->cpus_allowed, top_cpuset.effective_cpus)) continue; if (is_sched_load_balance(cp) && !cpumask_empty(cp->effective_cpus)) csa[csn++] = cp; /* skip @cp's subtree if not a partition root */ if (!is_partition_valid(cp)) pos_css = css_rightmost_descendant(pos_css); } rcu_read_unlock(); for (i = 0; i < csn; i++) csa[i]->pn = i; ndoms = csn; restart: /* Find the best partition (set of sched domains) */ for (i = 0; i < csn; i++) { struct cpuset *a = csa[i]; int apn = a->pn; for (j = 0; j < csn; j++) { struct cpuset *b = csa[j]; int bpn = b->pn; if (apn != bpn && cpusets_overlap(a, b)) { for (k = 0; k < csn; k++) { struct cpuset *c = csa[k]; if (c->pn == bpn) c->pn = apn; } ndoms--; /* one less element */ goto restart; } } } /* * Now we know how many domains to create. * Convert <csn, csa> to <ndoms, doms> and populate cpu masks. */ doms = alloc_sched_domains(ndoms); if (!doms) goto done; /* * The rest of the code, including the scheduler, can deal with * dattr==NULL case. No need to abort if alloc fails. */ dattr = kmalloc_array(ndoms, sizeof(struct sched_domain_attr), GFP_KERNEL); for (nslot = 0, i = 0; i < csn; i++) { struct cpuset *a = csa[i]; struct cpumask *dp; int apn = a->pn; if (apn < 0) { /* Skip completed partitions */ continue; } dp = doms[nslot]; if (nslot == ndoms) { static int warnings = 10; if (warnings) { pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n", nslot, ndoms, csn, i, apn); warnings--; } continue; } cpumask_clear(dp); if (dattr) *(dattr + nslot) = SD_ATTR_INIT; for (j = i; j < csn; j++) { struct cpuset *b = csa[j]; if (apn == b->pn) { cpumask_or(dp, dp, b->effective_cpus); cpumask_and(dp, dp, housekeeping_cpumask(HK_TYPE_DOMAIN)); if (dattr) update_domain_attr_tree(dattr + nslot, b); /* Done with this partition */ b->pn = -1; } } nslot++; } BUG_ON(nslot != ndoms); done: kfree(csa); /* * Fallback to the default domain if kmalloc() failed. * See comments in partition_sched_domains(). */ if (doms == NULL) ndoms = 1; *domains = doms; *attributes = dattr; return ndoms; } static void dl_update_tasks_root_domain(struct cpuset *cs) { struct css_task_iter it; struct task_struct *task; if (cs->nr_deadline_tasks == 0) return; css_task_iter_start(&cs->css, 0, &it); while ((task = css_task_iter_next(&it))) dl_add_task_root_domain(task); css_task_iter_end(&it); } static void dl_rebuild_rd_accounting(void) { struct cpuset *cs = NULL; struct cgroup_subsys_state *pos_css; lockdep_assert_held(&cpuset_mutex); lockdep_assert_cpus_held(); lockdep_assert_held(&sched_domains_mutex); rcu_read_lock(); /* * Clear default root domain DL accounting, it will be computed again * if a task belongs to it. */ dl_clear_root_domain(&def_root_domain); cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) { if (cpumask_empty(cs->effective_cpus)) { pos_css = css_rightmost_descendant(pos_css); continue; } css_get(&cs->css); rcu_read_unlock(); dl_update_tasks_root_domain(cs); rcu_read_lock(); css_put(&cs->css); } rcu_read_unlock(); } static void partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[], struct sched_domain_attr *dattr_new) { mutex_lock(&sched_domains_mutex); partition_sched_domains_locked(ndoms_new, doms_new, dattr_new); dl_rebuild_rd_accounting(); mutex_unlock(&sched_domains_mutex); } /* * Rebuild scheduler domains. * * If the flag 'sched_load_balance' of any cpuset with non-empty * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset * which has that flag enabled, or if any cpuset with a non-empty * 'cpus' is removed, then call this routine to rebuild the * scheduler's dynamic sched domains. * * Call with cpuset_mutex held. Takes cpus_read_lock(). */ static void rebuild_sched_domains_locked(void) { struct cgroup_subsys_state *pos_css; struct sched_domain_attr *attr; cpumask_var_t *doms; struct cpuset *cs; int ndoms; lockdep_assert_cpus_held(); lockdep_assert_held(&cpuset_mutex); /* * If we have raced with CPU hotplug, return early to avoid * passing doms with offlined cpu to partition_sched_domains(). * Anyways, cpuset_hotplug_workfn() will rebuild sched domains. * * With no CPUs in any subpartitions, top_cpuset's effective CPUs * should be the same as the active CPUs, so checking only top_cpuset * is enough to detect racing CPU offlines. */ if (cpumask_empty(subpartitions_cpus) && !cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask)) return; /* * With subpartition CPUs, however, the effective CPUs of a partition * root should be only a subset of the active CPUs. Since a CPU in any * partition root could be offlined, all must be checked. */ if (top_cpuset.nr_subparts) { rcu_read_lock(); cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) { if (!is_partition_valid(cs)) { pos_css = css_rightmost_descendant(pos_css); continue; } if (!cpumask_subset(cs->effective_cpus, cpu_active_mask)) { rcu_read_unlock(); return; } } rcu_read_unlock(); } /* Generate domain masks and attrs */ ndoms = generate_sched_domains(&doms, &attr); /* Have scheduler rebuild the domains */ partition_and_rebuild_sched_domains(ndoms, doms, attr); } #else /* !CONFIG_SMP */ static void rebuild_sched_domains_locked(void) { } #endif /* CONFIG_SMP */ void rebuild_sched_domains(void) { cpus_read_lock(); mutex_lock(&cpuset_mutex); rebuild_sched_domains_locked(); mutex_unlock(&cpuset_mutex); cpus_read_unlock(); } /** * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset. * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed * @new_cpus: the temp variable for the new effective_cpus mask * * Iterate through each task of @cs updating its cpus_allowed to the * effective cpuset's. As this function is called with cpuset_mutex held, * cpuset membership stays stable. For top_cpuset, task_cpu_possible_mask() * is used instead of effective_cpus to make sure all offline CPUs are also * included as hotplug code won't update cpumasks for tasks in top_cpuset. */ static void update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus) { struct css_task_iter it; struct task_struct *task; bool top_cs = cs == &top_cpuset; css_task_iter_start(&cs->css, 0, &it); while ((task = css_task_iter_next(&it))) { const struct cpumask *possible_mask = task_cpu_possible_mask(task); if (top_cs) { /* * Percpu kthreads in top_cpuset are ignored */ if (kthread_is_per_cpu(task)) continue; cpumask_andnot(new_cpus, possible_mask, subpartitions_cpus); } else { cpumask_and(new_cpus, possible_mask, cs->effective_cpus); } set_cpus_allowed_ptr(task, new_cpus); } css_task_iter_end(&it); } /** * compute_effective_cpumask - Compute the effective cpumask of the cpuset * @new_cpus: the temp variable for the new effective_cpus mask * @cs: the cpuset the need to recompute the new effective_cpus mask * @parent: the parent cpuset * * The result is valid only if the given cpuset isn't a partition root. */ static void compute_effective_cpumask(struct cpumask *new_cpus, struct cpuset *cs, struct cpuset *parent) { cpumask_and(new_cpus, cs->cpus_allowed, parent->effective_cpus); } /* * Commands for update_parent_effective_cpumask */ enum partition_cmd { partcmd_enable, /* Enable partition root */ partcmd_enablei, /* Enable isolated partition root */ partcmd_disable, /* Disable partition root */ partcmd_update, /* Update parent's effective_cpus */ partcmd_invalidate, /* Make partition invalid */ }; static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, int turning_on); static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs, struct tmpmasks *tmp); /* * Update partition exclusive flag * * Return: 0 if successful, an error code otherwise */ static int update_partition_exclusive(struct cpuset *cs, int new_prs) { bool exclusive = (new_prs > 0); if (exclusive && !is_cpu_exclusive(cs)) { if (update_flag(CS_CPU_EXCLUSIVE, cs, 1)) return PERR_NOTEXCL; } else if (!exclusive && is_cpu_exclusive(cs)) { /* Turning off CS_CPU_EXCLUSIVE will not return error */ update_flag(CS_CPU_EXCLUSIVE, cs, 0); } return 0; } /* * Update partition load balance flag and/or rebuild sched domain * * Changing load balance flag will automatically call * rebuild_sched_domains_locked(). * This function is for cgroup v2 only. */ static void update_partition_sd_lb(struct cpuset *cs, int old_prs) { int new_prs = cs->partition_root_state; bool rebuild_domains = (new_prs > 0) || (old_prs > 0); bool new_lb; /* * If cs is not a valid partition root, the load balance state * will follow its parent. */ if (new_prs > 0) { new_lb = (new_prs != PRS_ISOLATED); } else { new_lb = is_sched_load_balance(parent_cs(cs)); } if (new_lb != !!is_sched_load_balance(cs)) { rebuild_domains = true; if (new_lb) set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); else clear_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); } if (rebuild_domains) rebuild_sched_domains_locked(); } /* * tasks_nocpu_error - Return true if tasks will have no effective_cpus */ static bool tasks_nocpu_error(struct cpuset *parent, struct cpuset *cs, struct cpumask *xcpus) { /* * A populated partition (cs or parent) can't have empty effective_cpus */ return (cpumask_subset(parent->effective_cpus, xcpus) && partition_is_populated(parent, cs)) || (!cpumask_intersects(xcpus, cpu_active_mask) && partition_is_populated(cs, NULL)); } static void reset_partition_data(struct cpuset *cs) { struct cpuset *parent = parent_cs(cs); if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) return; lockdep_assert_held(&callback_lock); cs->nr_subparts = 0; if (cpumask_empty(cs->exclusive_cpus)) { cpumask_clear(cs->effective_xcpus); if (is_cpu_exclusive(cs)) clear_bit(CS_CPU_EXCLUSIVE, &cs->flags); } if (!cpumask_and(cs->effective_cpus, parent->effective_cpus, cs->cpus_allowed)) { cs->use_parent_ecpus = true; parent->child_ecpus_count++; cpumask_copy(cs->effective_cpus, parent->effective_cpus); } } /* * partition_xcpus_newstate - Exclusive CPUs state change * @old_prs: old partition_root_state * @new_prs: new partition_root_state * @xcpus: exclusive CPUs with state change */ static void partition_xcpus_newstate(int old_prs, int new_prs, struct cpumask *xcpus) { WARN_ON_ONCE(old_prs == new_prs); if (new_prs == PRS_ISOLATED) cpumask_or(isolated_cpus, isolated_cpus, xcpus); else cpumask_andnot(isolated_cpus, isolated_cpus, xcpus); } /* * partition_xcpus_add - Add new exclusive CPUs to partition * @new_prs: new partition_root_state * @parent: parent cpuset * @xcpus: exclusive CPUs to be added * Return: true if isolated_cpus modified, false otherwise * * Remote partition if parent == NULL */ static bool partition_xcpus_add(int new_prs, struct cpuset *parent, struct cpumask *xcpus) { bool isolcpus_updated; WARN_ON_ONCE(new_prs < 0); lockdep_assert_held(&callback_lock); if (!parent) parent = &top_cpuset; if (parent == &top_cpuset) cpumask_or(subpartitions_cpus, subpartitions_cpus, xcpus); isolcpus_updated = (new_prs != parent->partition_root_state); if (isolcpus_updated) partition_xcpus_newstate(parent->partition_root_state, new_prs, xcpus); cpumask_andnot(parent->effective_cpus, parent->effective_cpus, xcpus); return isolcpus_updated; } /* * partition_xcpus_del - Remove exclusive CPUs from partition * @old_prs: old partition_root_state * @parent: parent cpuset * @xcpus: exclusive CPUs to be removed * Return: true if isolated_cpus modified, false otherwise * * Remote partition if parent == NULL */ static bool partition_xcpus_del(int old_prs, struct cpuset *parent, struct cpumask *xcpus) { bool isolcpus_updated; WARN_ON_ONCE(old_prs < 0); lockdep_assert_held(&callback_lock); if (!parent) parent = &top_cpuset; if (parent == &top_cpuset) cpumask_andnot(subpartitions_cpus, subpartitions_cpus, xcpus); isolcpus_updated = (old_prs != parent->partition_root_state); if (isolcpus_updated) partition_xcpus_newstate(old_prs, parent->partition_root_state, xcpus); cpumask_and(xcpus, xcpus, cpu_active_mask); cpumask_or(parent->effective_cpus, parent->effective_cpus, xcpus); return isolcpus_updated; } static void update_unbound_workqueue_cpumask(bool isolcpus_updated) { int ret; lockdep_assert_cpus_held(); if (!isolcpus_updated) return; ret = workqueue_unbound_exclude_cpumask(isolated_cpus); WARN_ON_ONCE(ret < 0); } /** * cpuset_cpu_is_isolated - Check if the given CPU is isolated * @cpu: the CPU number to be checked * Return: true if CPU is used in an isolated partition, false otherwise */ bool cpuset_cpu_is_isolated(int cpu) { return cpumask_test_cpu(cpu, isolated_cpus); } EXPORT_SYMBOL_GPL(cpuset_cpu_is_isolated); /* * compute_effective_exclusive_cpumask - compute effective exclusive CPUs * @cs: cpuset * @xcpus: effective exclusive CPUs value to be set * Return: true if xcpus is not empty, false otherwise. * * Starting with exclusive_cpus (cpus_allowed if exclusive_cpus is not set), * it must be a subset of cpus_allowed and parent's effective_xcpus. */ static bool compute_effective_exclusive_cpumask(struct cpuset *cs, struct cpumask *xcpus) { struct cpuset *parent = parent_cs(cs); if (!xcpus) xcpus = cs->effective_xcpus; if (!cpumask_empty(cs->exclusive_cpus)) cpumask_and(xcpus, cs->exclusive_cpus, cs->cpus_allowed); else cpumask_copy(xcpus, cs->cpus_allowed); return cpumask_and(xcpus, xcpus, parent->effective_xcpus); } static inline bool is_remote_partition(struct cpuset *cs) { return !list_empty(&cs->remote_sibling); } static inline bool is_local_partition(struct cpuset *cs) { return is_partition_valid(cs) && !is_remote_partition(cs); } /* * remote_partition_enable - Enable current cpuset as a remote partition root * @cs: the cpuset to update * @new_prs: new partition_root_state * @tmp: temparary masks * Return: 1 if successful, 0 if error * * Enable the current cpuset to become a remote partition root taking CPUs * directly from the top cpuset. cpuset_mutex must be held by the caller. */ static int remote_partition_enable(struct cpuset *cs, int new_prs, struct tmpmasks *tmp) { bool isolcpus_updated; /* * The user must have sysadmin privilege. */ if (!capable(CAP_SYS_ADMIN)) return 0; /* * The requested exclusive_cpus must not be allocated to other * partitions and it can't use up all the root's effective_cpus. * * Note that if there is any local partition root above it or * remote partition root underneath it, its exclusive_cpus must * have overlapped with subpartitions_cpus. */ compute_effective_exclusive_cpumask(cs, tmp->new_cpus); if (cpumask_empty(tmp->new_cpus) || cpumask_intersects(tmp->new_cpus, subpartitions_cpus) || cpumask_subset(top_cpuset.effective_cpus, tmp->new_cpus)) return 0; spin_lock_irq(&callback_lock); isolcpus_updated = partition_xcpus_add(new_prs, NULL, tmp->new_cpus); list_add(&cs->remote_sibling, &remote_children); if (cs->use_parent_ecpus) { struct cpuset *parent = parent_cs(cs); cs->use_parent_ecpus = false; parent->child_ecpus_count--; } spin_unlock_irq(&callback_lock); update_unbound_workqueue_cpumask(isolcpus_updated); /* * Proprogate changes in top_cpuset's effective_cpus down the hierarchy. */ update_tasks_cpumask(&top_cpuset, tmp->new_cpus); update_sibling_cpumasks(&top_cpuset, NULL, tmp); return 1; } /* * remote_partition_disable - Remove current cpuset from remote partition list * @cs: the cpuset to update * @tmp: temparary masks * * The effective_cpus is also updated. * * cpuset_mutex must be held by the caller. */ static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp) { bool isolcpus_updated; compute_effective_exclusive_cpumask(cs, tmp->new_cpus); WARN_ON_ONCE(!is_remote_partition(cs)); WARN_ON_ONCE(!cpumask_subset(tmp->new_cpus, subpartitions_cpus)); spin_lock_irq(&callback_lock); list_del_init(&cs->remote_sibling); isolcpus_updated = partition_xcpus_del(cs->partition_root_state, NULL, tmp->new_cpus); cs->partition_root_state = -cs->partition_root_state; if (!cs->prs_err) cs->prs_err = PERR_INVCPUS; reset_partition_data(cs); spin_unlock_irq(&callback_lock); update_unbound_workqueue_cpumask(isolcpus_updated); /* * Proprogate changes in top_cpuset's effective_cpus down the hierarchy. */ update_tasks_cpumask(&top_cpuset, tmp->new_cpus); update_sibling_cpumasks(&top_cpuset, NULL, tmp); } /* * remote_cpus_update - cpus_exclusive change of remote partition * @cs: the cpuset to be updated * @newmask: the new effective_xcpus mask * @tmp: temparary masks * * top_cpuset and subpartitions_cpus will be updated or partition can be * invalidated. */ static void remote_cpus_update(struct cpuset *cs, struct cpumask *newmask, struct tmpmasks *tmp) { bool adding, deleting; int prs = cs->partition_root_state; int isolcpus_updated = 0; if (WARN_ON_ONCE(!is_remote_partition(cs))) return; WARN_ON_ONCE(!cpumask_subset(cs->effective_xcpus, subpartitions_cpus)); if (cpumask_empty(newmask)) goto invalidate; adding = cpumask_andnot(tmp->addmask, newmask, cs->effective_xcpus); deleting = cpumask_andnot(tmp->delmask, cs->effective_xcpus, newmask); /* * Additions of remote CPUs is only allowed if those CPUs are * not allocated to other partitions and there are effective_cpus * left in the top cpuset. */ if (adding && (!capable(CAP_SYS_ADMIN) || cpumask_intersects(tmp->addmask, subpartitions_cpus) || cpumask_subset(top_cpuset.effective_cpus, tmp->addmask))) goto invalidate; spin_lock_irq(&callback_lock); if (adding) isolcpus_updated += partition_xcpus_add(prs, NULL, tmp->addmask); if (deleting) isolcpus_updated += partition_xcpus_del(prs, NULL, tmp->delmask); spin_unlock_irq(&callback_lock); update_unbound_workqueue_cpumask(isolcpus_updated); /* * Proprogate changes in top_cpuset's effective_cpus down the hierarchy. */ update_tasks_cpumask(&top_cpuset, tmp->new_cpus); update_sibling_cpumasks(&top_cpuset, NULL, tmp); return; invalidate: remote_partition_disable(cs, tmp); } /* * remote_partition_check - check if a child remote partition needs update * @cs: the cpuset to be updated * @newmask: the new effective_xcpus mask * @delmask: temporary mask for deletion (not in tmp) * @tmp: temparary masks * * This should be called before the given cs has updated its cpus_allowed * and/or effective_xcpus. */ static void remote_partition_check(struct cpuset *cs, struct cpumask *newmask, struct cpumask *delmask, struct tmpmasks *tmp) { struct cpuset *child, *next; int disable_cnt = 0; /* * Compute the effective exclusive CPUs that will be deleted. */ if (!cpumask_andnot(delmask, cs->effective_xcpus, newmask) || !cpumask_intersects(delmask, subpartitions_cpus)) return; /* No deletion of exclusive CPUs in partitions */ /* * Searching the remote children list to look for those that will * be impacted by the deletion of exclusive CPUs. * * Since a cpuset must be removed from the remote children list * before it can go offline and holding cpuset_mutex will prevent * any change in cpuset status. RCU read lock isn't needed. */ lockdep_assert_held(&cpuset_mutex); list_for_each_entry_safe(child, next, &remote_children, remote_sibling) if (cpumask_intersects(child->effective_cpus, delmask)) { remote_partition_disable(child, tmp); disable_cnt++; } if (disable_cnt) rebuild_sched_domains_locked(); } /* * prstate_housekeeping_conflict - check for partition & housekeeping conflicts * @prstate: partition root state to be checked * @new_cpus: cpu mask * Return: true if there is conflict, false otherwise * * CPUs outside of housekeeping_cpumask(HK_TYPE_DOMAIN) can only be used in * an isolated partition. */ static bool prstate_housekeeping_conflict(int prstate, struct cpumask *new_cpus) { const struct cpumask *hk_domain = housekeeping_cpumask(HK_TYPE_DOMAIN); bool all_in_hk = cpumask_subset(new_cpus, hk_domain); if (!all_in_hk && (prstate != PRS_ISOLATED)) return true; return false; } /** * update_parent_effective_cpumask - update effective_cpus mask of parent cpuset * @cs: The cpuset that requests change in partition root state * @cmd: Partition root state change command * @newmask: Optional new cpumask for partcmd_update * @tmp: Temporary addmask and delmask * Return: 0 or a partition root state error code * * For partcmd_enable*, the cpuset is being transformed from a non-partition * root to a partition root. The effective_xcpus (cpus_allowed if * effective_xcpus not set) mask of the given cpuset will be taken away from * parent's effective_cpus. The function will return 0 if all the CPUs listed * in effective_xcpus can be granted or an error code will be returned. * * For partcmd_disable, the cpuset is being transformed from a partition * root back to a non-partition root. Any CPUs in effective_xcpus will be * given back to parent's effective_cpus. 0 will always be returned. * * For partcmd_update, if the optional newmask is specified, the cpu list is * to be changed from effective_xcpus to newmask. Otherwise, effective_xcpus is * assumed to remain the same. The cpuset should either be a valid or invalid * partition root. The partition root state may change from valid to invalid * or vice versa. An error code will be returned if transitioning from * invalid to valid violates the exclusivity rule. * * For partcmd_invalidate, the current partition will be made invalid. * * The partcmd_enable* and partcmd_disable commands are used by * update_prstate(). An error code may be returned and the caller will check * for error. * * The partcmd_update command is used by update_cpumasks_hier() with newmask * NULL and update_cpumask() with newmask set. The partcmd_invalidate is used * by update_cpumask() with NULL newmask. In both cases, the callers won't * check for error and so partition_root_state and prs_error will be updated * directly. */ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, struct cpumask *newmask, struct tmpmasks *tmp) { struct cpuset *parent = parent_cs(cs); int adding; /* Adding cpus to parent's effective_cpus */ int deleting; /* Deleting cpus from parent's effective_cpus */ int old_prs, new_prs; int part_error = PERR_NONE; /* Partition error? */ int subparts_delta = 0; struct cpumask *xcpus; /* cs effective_xcpus */ int isolcpus_updated = 0; bool nocpu; lockdep_assert_held(&cpuset_mutex); /* * new_prs will only be changed for the partcmd_update and * partcmd_invalidate commands. */ adding = deleting = false; old_prs = new_prs = cs->partition_root_state; xcpus = !cpumask_empty(cs->exclusive_cpus) ? cs->effective_xcpus : cs->cpus_allowed; if (cmd == partcmd_invalidate) { if (is_prs_invalid(old_prs)) return 0; /* * Make the current partition invalid. */ if (is_partition_valid(parent)) adding = cpumask_and(tmp->addmask, xcpus, parent->effective_xcpus); if (old_prs > 0) { new_prs = -old_prs; subparts_delta--; } goto write_error; } /* * The parent must be a partition root. * The new cpumask, if present, or the current cpus_allowed must * not be empty. */ if (!is_partition_valid(parent)) { return is_partition_invalid(parent) ? PERR_INVPARENT : PERR_NOTPART; } if (!newmask && cpumask_empty(cs->cpus_allowed)) return PERR_CPUSEMPTY; nocpu = tasks_nocpu_error(parent, cs, xcpus); if ((cmd == partcmd_enable) || (cmd == partcmd_enablei)) { /* * Enabling partition root is not allowed if its * effective_xcpus is empty or doesn't overlap with * parent's effective_xcpus. */ if (cpumask_empty(xcpus) || !cpumask_intersects(xcpus, parent->effective_xcpus)) return PERR_INVCPUS; if (prstate_housekeeping_conflict(new_prs, xcpus)) return PERR_HKEEPING; /* * A parent can be left with no CPU as long as there is no * task directly associated with the parent partition. */ if (nocpu) return PERR_NOCPUS; cpumask_copy(tmp->delmask, xcpus); deleting = true; subparts_delta++; new_prs = (cmd == partcmd_enable) ? PRS_ROOT : PRS_ISOLATED; } else if (cmd == partcmd_disable) { /* * May need to add cpus to parent's effective_cpus for * valid partition root. */ adding = !is_prs_invalid(old_prs) && cpumask_and(tmp->addmask, xcpus, parent->effective_xcpus); if (adding) subparts_delta--; new_prs = PRS_MEMBER; } else if (newmask) { /* * Empty cpumask is not allowed */ if (cpumask_empty(newmask)) { part_error = PERR_CPUSEMPTY; goto write_error; } /* * partcmd_update with newmask: * * Compute add/delete mask to/from effective_cpus * * For valid partition: * addmask = exclusive_cpus & ~newmask * & parent->effective_xcpus * delmask = newmask & ~exclusive_cpus * & parent->effective_xcpus * * For invalid partition: * delmask = newmask & parent->effective_xcpus */ if (is_prs_invalid(old_prs)) { adding = false; deleting = cpumask_and(tmp->delmask, newmask, parent->effective_xcpus); } else { cpumask_andnot(tmp->addmask, xcpus, newmask); adding = cpumask_and(tmp->addmask, tmp->addmask, parent->effective_xcpus); cpumask_andnot(tmp->delmask, newmask, xcpus); deleting = cpumask_and(tmp->delmask, tmp->delmask, parent->effective_xcpus); } /* * Make partition invalid if parent's effective_cpus could * become empty and there are tasks in the parent. */ if (nocpu && (!adding || !cpumask_intersects(tmp->addmask, cpu_active_mask))) { part_error = PERR_NOCPUS; deleting = false; adding = cpumask_and(tmp->addmask, xcpus, parent->effective_xcpus); } } else { /* * partcmd_update w/o newmask * * delmask = effective_xcpus & parent->effective_cpus * * This can be called from: * 1) update_cpumasks_hier() * 2) cpuset_hotplug_update_tasks() * * Check to see if it can be transitioned from valid to * invalid partition or vice versa. * * A partition error happens when parent has tasks and all * its effective CPUs will have to be distributed out. */ WARN_ON_ONCE(!is_partition_valid(parent)); if (nocpu) { part_error = PERR_NOCPUS; if (is_partition_valid(cs)) adding = cpumask_and(tmp->addmask, xcpus, parent->effective_xcpus); } else if (is_partition_invalid(cs) && cpumask_subset(xcpus, parent->effective_xcpus)) { struct cgroup_subsys_state *css; struct cpuset *child; bool exclusive = true; /* * Convert invalid partition to valid has to * pass the cpu exclusivity test. */ rcu_read_lock(); cpuset_for_each_child(child, css, parent) { if (child == cs) continue; if (!cpusets_are_exclusive(cs, child)) { exclusive = false; break; } } rcu_read_unlock(); if (exclusive) deleting = cpumask_and(tmp->delmask, xcpus, parent->effective_cpus); else part_error = PERR_NOTEXCL; } } write_error: if (part_error) WRITE_ONCE(cs->prs_err, part_error); if (cmd == partcmd_update) { /* * Check for possible transition between valid and invalid * partition root. */ switch (cs->partition_root_state) { case PRS_ROOT: case PRS_ISOLATED: if (part_error) { new_prs = -old_prs; subparts_delta--; } break; case PRS_INVALID_ROOT: case PRS_INVALID_ISOLATED: if (!part_error) { new_prs = -old_prs; subparts_delta++; } break; } } if (!adding && !deleting && (new_prs == old_prs)) return 0; /* * Transitioning between invalid to valid or vice versa may require * changing CS_CPU_EXCLUSIVE. In the case of partcmd_update, * validate_change() has already been successfully called and * CPU lists in cs haven't been updated yet. So defer it to later. */ if ((old_prs != new_prs) && (cmd != partcmd_update)) { int err = update_partition_exclusive(cs, new_prs); if (err) return err; } /* * Change the parent's effective_cpus & effective_xcpus (top cpuset * only). * * Newly added CPUs will be removed from effective_cpus and * newly deleted ones will be added back to effective_cpus. */ spin_lock_irq(&callback_lock); if (old_prs != new_prs) { cs->partition_root_state = new_prs; if (new_prs <= 0) cs->nr_subparts = 0; } /* * Adding to parent's effective_cpus means deletion CPUs from cs * and vice versa. */ if (adding) isolcpus_updated += partition_xcpus_del(old_prs, parent, tmp->addmask); if (deleting) isolcpus_updated += partition_xcpus_add(new_prs, parent, tmp->delmask); if (is_partition_valid(parent)) { parent->nr_subparts += subparts_delta; WARN_ON_ONCE(parent->nr_subparts < 0); } spin_unlock_irq(&callback_lock); update_unbound_workqueue_cpumask(isolcpus_updated); if ((old_prs != new_prs) && (cmd == partcmd_update)) update_partition_exclusive(cs, new_prs); if (adding || deleting) { update_tasks_cpumask(parent, tmp->addmask); update_sibling_cpumasks(parent, cs, tmp); } /* * For partcmd_update without newmask, it is being called from * cpuset_hotplug_workfn() where cpus_read_lock() wasn't taken. * Update the load balance flag and scheduling domain if * cpus_read_trylock() is successful. */ if ((cmd == partcmd_update) && !newmask && cpus_read_trylock()) { update_partition_sd_lb(cs, old_prs); cpus_read_unlock(); } notify_partition_change(cs, old_prs); return 0; } /** * compute_partition_effective_cpumask - compute effective_cpus for partition * @cs: partition root cpuset * @new_ecpus: previously computed effective_cpus to be updated * * Compute the effective_cpus of a partition root by scanning effective_xcpus * of child partition roots and excluding their effective_xcpus. * * This has the side effect of invalidating valid child partition roots, * if necessary. Since it is called from either cpuset_hotplug_update_tasks() * or update_cpumasks_hier() where parent and children are modified * successively, we don't need to call update_parent_effective_cpumask() * and the child's effective_cpus will be updated in later iterations. * * Note that rcu_read_lock() is assumed to be held. */ static void compute_partition_effective_cpumask(struct cpuset *cs, struct cpumask *new_ecpus) { struct cgroup_subsys_state *css; struct cpuset *child; bool populated = partition_is_populated(cs, NULL); /* * Check child partition roots to see if they should be * invalidated when * 1) child effective_xcpus not a subset of new * excluisve_cpus * 2) All the effective_cpus will be used up and cp * has tasks */ compute_effective_exclusive_cpumask(cs, new_ecpus); cpumask_and(new_ecpus, new_ecpus, cpu_active_mask); rcu_read_lock(); cpuset_for_each_child(child, css, cs) { if (!is_partition_valid(child)) continue; child->prs_err = 0; if (!cpumask_subset(child->effective_xcpus, cs->effective_xcpus)) child->prs_err = PERR_INVCPUS; else if (populated && cpumask_subset(new_ecpus, child->effective_xcpus)) child->prs_err = PERR_NOCPUS; if (child->prs_err) { int old_prs = child->partition_root_state; /* * Invalidate child partition */ spin_lock_irq(&callback_lock); make_partition_invalid(child); cs->nr_subparts--; child->nr_subparts = 0; spin_unlock_irq(&callback_lock); notify_partition_change(child, old_prs); continue; } cpumask_andnot(new_ecpus, new_ecpus, child->effective_xcpus); } rcu_read_unlock(); } /* * update_cpumasks_hier() flags */ #define HIER_CHECKALL 0x01 /* Check all cpusets with no skipping */ #define HIER_NO_SD_REBUILD 0x02 /* Don't rebuild sched domains */ /* * update_cpumasks_hier - Update effective cpumasks and tasks in the subtree * @cs: the cpuset to consider * @tmp: temp variables for calculating effective_cpus & partition setup * @force: don't skip any descendant cpusets if set * * When configured cpumask is changed, the effective cpumasks of this cpuset * and all its descendants need to be updated. * * On legacy hierarchy, effective_cpus will be the same with cpu_allowed. * * Called with cpuset_mutex held */ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, int flags) { struct cpuset *cp; struct cgroup_subsys_state *pos_css; bool need_rebuild_sched_domains = false; int old_prs, new_prs; rcu_read_lock(); cpuset_for_each_descendant_pre(cp, pos_css, cs) { struct cpuset *parent = parent_cs(cp); bool remote = is_remote_partition(cp); bool update_parent = false; /* * Skip descendent remote partition that acquires CPUs * directly from top cpuset unless it is cs. */ if (remote && (cp != cs)) { pos_css = css_rightmost_descendant(pos_css); continue; } /* * Update effective_xcpus if exclusive_cpus set. * The case when exclusive_cpus isn't set is handled later. */ if (!cpumask_empty(cp->exclusive_cpus) && (cp != cs)) { spin_lock_irq(&callback_lock); compute_effective_exclusive_cpumask(cp, NULL); spin_unlock_irq(&callback_lock); } old_prs = new_prs = cp->partition_root_state; if (remote || (is_partition_valid(parent) && is_partition_valid(cp))) compute_partition_effective_cpumask(cp, tmp->new_cpus); else compute_effective_cpumask(tmp->new_cpus, cp, parent); /* * A partition with no effective_cpus is allowed as long as * there is no task associated with it. Call * update_parent_effective_cpumask() to check it. */ if (is_partition_valid(cp) && cpumask_empty(tmp->new_cpus)) { update_parent = true; goto update_parent_effective; } /* * If it becomes empty, inherit the effective mask of the * parent, which is guaranteed to have some CPUs unless * it is a partition root that has explicitly distributed * out all its CPUs. */ if (is_in_v2_mode() && !remote && cpumask_empty(tmp->new_cpus)) { cpumask_copy(tmp->new_cpus, parent->effective_cpus); if (!cp->use_parent_ecpus) { cp->use_parent_ecpus = true; parent->child_ecpus_count++; } } else if (cp->use_parent_ecpus) { cp->use_parent_ecpus = false; WARN_ON_ONCE(!parent->child_ecpus_count); parent->child_ecpus_count--; } if (remote) goto get_css; /* * Skip the whole subtree if * 1) the cpumask remains the same, * 2) has no partition root state, * 3) HIER_CHECKALL flag not set, and * 4) for v2 load balance state same as its parent. */ if (!cp->partition_root_state && !(flags & HIER_CHECKALL) && cpumask_equal(tmp->new_cpus, cp->effective_cpus) && (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || (is_sched_load_balance(parent) == is_sched_load_balance(cp)))) { pos_css = css_rightmost_descendant(pos_css); continue; } update_parent_effective: /* * update_parent_effective_cpumask() should have been called * for cs already in update_cpumask(). We should also call * update_tasks_cpumask() again for tasks in the parent * cpuset if the parent's effective_cpus changes. */ if ((cp != cs) && old_prs) { switch (parent->partition_root_state) { case PRS_ROOT: case PRS_ISOLATED: update_parent = true; break; default: /* * When parent is not a partition root or is * invalid, child partition roots become * invalid too. */ if (is_partition_valid(cp)) new_prs = -cp->partition_root_state; WRITE_ONCE(cp->prs_err, is_partition_invalid(parent) ? PERR_INVPARENT : PERR_NOTPART); break; } } get_css: if (!css_tryget_online(&cp->css)) continue; rcu_read_unlock(); if (update_parent) { update_parent_effective_cpumask(cp, partcmd_update, NULL, tmp); /* * The cpuset partition_root_state may become * invalid. Capture it. */ new_prs = cp->partition_root_state; } spin_lock_irq(&callback_lock); cpumask_copy(cp->effective_cpus, tmp->new_cpus); cp->partition_root_state = new_prs; /* * Make sure effective_xcpus is properly set for a valid * partition root. */ if ((new_prs > 0) && cpumask_empty(cp->exclusive_cpus)) cpumask_and(cp->effective_xcpus, cp->cpus_allowed, parent->effective_xcpus); else if (new_prs < 0) reset_partition_data(cp); spin_unlock_irq(&callback_lock); notify_partition_change(cp, old_prs); WARN_ON(!is_in_v2_mode() && !cpumask_equal(cp->cpus_allowed, cp->effective_cpus)); update_tasks_cpumask(cp, cp->effective_cpus); /* * On default hierarchy, inherit the CS_SCHED_LOAD_BALANCE * from parent if current cpuset isn't a valid partition root * and their load balance states differ. */ if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && !is_partition_valid(cp) && (is_sched_load_balance(parent) != is_sched_load_balance(cp))) { if (is_sched_load_balance(parent)) set_bit(CS_SCHED_LOAD_BALANCE, &cp->flags); else clear_bit(CS_SCHED_LOAD_BALANCE, &cp->flags); } /* * On legacy hierarchy, if the effective cpumask of any non- * empty cpuset is changed, we need to rebuild sched domains. * On default hierarchy, the cpuset needs to be a partition * root as well. */ if (!cpumask_empty(cp->cpus_allowed) && is_sched_load_balance(cp) && (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || is_partition_valid(cp))) need_rebuild_sched_domains = true; rcu_read_lock(); css_put(&cp->css); } rcu_read_unlock(); if (need_rebuild_sched_domains && !(flags & HIER_NO_SD_REBUILD)) rebuild_sched_domains_locked(); } /** * update_sibling_cpumasks - Update siblings cpumasks * @parent: Parent cpuset * @cs: Current cpuset * @tmp: Temp variables */ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs, struct tmpmasks *tmp) { struct cpuset *sibling; struct cgroup_subsys_state *pos_css; lockdep_assert_held(&cpuset_mutex); /* * Check all its siblings and call update_cpumasks_hier() * if their effective_cpus will need to be changed. * * With the addition of effective_xcpus which is a subset of * cpus_allowed. It is possible a change in parent's effective_cpus * due to a change in a child partition's effective_xcpus will impact * its siblings even if they do not inherit parent's effective_cpus * directly. * * The update_cpumasks_hier() function may sleep. So we have to * release the RCU read lock before calling it. HIER_NO_SD_REBUILD * flag is used to suppress rebuild of sched domains as the callers * will take care of that. */ rcu_read_lock(); cpuset_for_each_child(sibling, pos_css, parent) { if (sibling == cs) continue; if (!sibling->use_parent_ecpus && !is_partition_valid(sibling)) { compute_effective_cpumask(tmp->new_cpus, sibling, parent); if (cpumask_equal(tmp->new_cpus, sibling->effective_cpus)) continue; } if (!css_tryget_online(&sibling->css)) continue; rcu_read_unlock(); update_cpumasks_hier(sibling, tmp, HIER_NO_SD_REBUILD); rcu_read_lock(); css_put(&sibling->css); } rcu_read_unlock(); } /** * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it * @cs: the cpuset to consider * @trialcs: trial cpuset * @buf: buffer of cpu numbers written to this cpuset */ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, const char *buf) { int retval; struct tmpmasks tmp; struct cpuset *parent = parent_cs(cs); bool invalidate = false; int hier_flags = 0; int old_prs = cs->partition_root_state; /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */ if (cs == &top_cpuset) return -EACCES; /* * An empty cpus_allowed is ok only if the cpuset has no tasks. * Since cpulist_parse() fails on an empty mask, we special case * that parsing. The validate_change() call ensures that cpusets * with tasks have cpus. */ if (!*buf) { cpumask_clear(trialcs->cpus_allowed); cpumask_clear(trialcs->effective_xcpus); } else { retval = cpulist_parse(buf, trialcs->cpus_allowed); if (retval < 0) return retval; if (!cpumask_subset(trialcs->cpus_allowed, top_cpuset.cpus_allowed)) return -EINVAL; /* * When exclusive_cpus isn't explicitly set, it is constrainted * by cpus_allowed and parent's effective_xcpus. Otherwise, * trialcs->effective_xcpus is used as a temporary cpumask * for checking validity of the partition root. */ if (!cpumask_empty(trialcs->exclusive_cpus) || is_partition_valid(cs)) compute_effective_exclusive_cpumask(trialcs, NULL); } /* Nothing to do if the cpus didn't change */ if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed)) return 0; if (alloc_cpumasks(NULL, &tmp)) return -ENOMEM; if (old_prs) { if (is_partition_valid(cs) && cpumask_empty(trialcs->effective_xcpus)) { invalidate = true; cs->prs_err = PERR_INVCPUS; } else if (prstate_housekeeping_conflict(old_prs, trialcs->effective_xcpus)) { invalidate = true; cs->prs_err = PERR_HKEEPING; } else if (tasks_nocpu_error(parent, cs, trialcs->effective_xcpus)) { invalidate = true; cs->prs_err = PERR_NOCPUS; } } /* * Check all the descendants in update_cpumasks_hier() if * effective_xcpus is to be changed. */ if (!cpumask_equal(cs->effective_xcpus, trialcs->effective_xcpus)) hier_flags = HIER_CHECKALL; retval = validate_change(cs, trialcs); if ((retval == -EINVAL) && cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) { struct cgroup_subsys_state *css; struct cpuset *cp; /* * The -EINVAL error code indicates that partition sibling * CPU exclusivity rule has been violated. We still allow * the cpumask change to proceed while invalidating the * partition. However, any conflicting sibling partitions * have to be marked as invalid too. */ invalidate = true; rcu_read_lock(); cpuset_for_each_child(cp, css, parent) { struct cpumask *xcpus = fetch_xcpus(trialcs); if (is_partition_valid(cp) && cpumask_intersects(xcpus, cp->effective_xcpus)) { rcu_read_unlock(); update_parent_effective_cpumask(cp, partcmd_invalidate, NULL, &tmp); rcu_read_lock(); } } rcu_read_unlock(); retval = 0; } if (retval < 0) goto out_free; if (is_partition_valid(cs) || (is_partition_invalid(cs) && !invalidate)) { struct cpumask *xcpus = trialcs->effective_xcpus; if (cpumask_empty(xcpus) && is_partition_invalid(cs)) xcpus = trialcs->cpus_allowed; /* * Call remote_cpus_update() to handle valid remote partition */ if (is_remote_partition(cs)) remote_cpus_update(cs, xcpus, &tmp); else if (invalidate) update_parent_effective_cpumask(cs, partcmd_invalidate, NULL, &tmp); else update_parent_effective_cpumask(cs, partcmd_update, xcpus, &tmp); } else if (!cpumask_empty(cs->exclusive_cpus)) { /* * Use trialcs->effective_cpus as a temp cpumask */ remote_partition_check(cs, trialcs->effective_xcpus, trialcs->effective_cpus, &tmp); } spin_lock_irq(&callback_lock); cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); cpumask_copy(cs->effective_xcpus, trialcs->effective_xcpus); if ((old_prs > 0) && !is_partition_valid(cs)) reset_partition_data(cs); spin_unlock_irq(&callback_lock); /* effective_cpus/effective_xcpus will be updated here */ update_cpumasks_hier(cs, &tmp, hier_flags); /* Update CS_SCHED_LOAD_BALANCE and/or sched_domains, if necessary */ if (cs->partition_root_state) update_partition_sd_lb(cs, old_prs); out_free: free_cpumasks(NULL, &tmp); return retval; } /** * update_exclusive_cpumask - update the exclusive_cpus mask of a cpuset * @cs: the cpuset to consider * @trialcs: trial cpuset * @buf: buffer of cpu numbers written to this cpuset * * The tasks' cpumask will be updated if cs is a valid partition root. */ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs, const char *buf) { int retval; struct tmpmasks tmp; struct cpuset *parent = parent_cs(cs); bool invalidate = false; int hier_flags = 0; int old_prs = cs->partition_root_state; if (!*buf) { cpumask_clear(trialcs->exclusive_cpus); cpumask_clear(trialcs->effective_xcpus); } else { retval = cpulist_parse(buf, trialcs->exclusive_cpus); if (retval < 0) return retval; if (!is_cpu_exclusive(cs)) set_bit(CS_CPU_EXCLUSIVE, &trialcs->flags); } /* Nothing to do if the CPUs didn't change */ if (cpumask_equal(cs->exclusive_cpus, trialcs->exclusive_cpus)) return 0; if (*buf) compute_effective_exclusive_cpumask(trialcs, NULL); /* * Check all the descendants in update_cpumasks_hier() if * effective_xcpus is to be changed. */ if (!cpumask_equal(cs->effective_xcpus, trialcs->effective_xcpus)) hier_flags = HIER_CHECKALL; retval = validate_change(cs, trialcs); if (retval) return retval; if (alloc_cpumasks(NULL, &tmp)) return -ENOMEM; if (old_prs) { if (cpumask_empty(trialcs->effective_xcpus)) { invalidate = true; cs->prs_err = PERR_INVCPUS; } else if (prstate_housekeeping_conflict(old_prs, trialcs->effective_xcpus)) { invalidate = true; cs->prs_err = PERR_HKEEPING; } else if (tasks_nocpu_error(parent, cs, trialcs->effective_xcpus)) { invalidate = true; cs->prs_err = PERR_NOCPUS; } if (is_remote_partition(cs)) { if (invalidate) remote_partition_disable(cs, &tmp); else remote_cpus_update(cs, trialcs->effective_xcpus, &tmp); } else if (invalidate) { update_parent_effective_cpumask(cs, partcmd_invalidate, NULL, &tmp); } else { update_parent_effective_cpumask(cs, partcmd_update, trialcs->effective_xcpus, &tmp); } } else if (!cpumask_empty(trialcs->exclusive_cpus)) { /* * Use trialcs->effective_cpus as a temp cpumask */ remote_partition_check(cs, trialcs->effective_xcpus, trialcs->effective_cpus, &tmp); } spin_lock_irq(&callback_lock); cpumask_copy(cs->exclusive_cpus, trialcs->exclusive_cpus); cpumask_copy(cs->effective_xcpus, trialcs->effective_xcpus); if ((old_prs > 0) && !is_partition_valid(cs)) reset_partition_data(cs); spin_unlock_irq(&callback_lock); /* * Call update_cpumasks_hier() to update effective_cpus/effective_xcpus * of the subtree when it is a valid partition root or effective_xcpus * is updated. */ if (is_partition_valid(cs) || hier_flags) update_cpumasks_hier(cs, &tmp, hier_flags); /* Update CS_SCHED_LOAD_BALANCE and/or sched_domains, if necessary */ if (cs->partition_root_state) update_partition_sd_lb(cs, old_prs); free_cpumasks(NULL, &tmp); return 0; } /* * Migrate memory region from one set of nodes to another. This is * performed asynchronously as it can be called from process migration path * holding locks involved in process management. All mm migrations are * performed in the queued order and can be waited for by flushing * cpuset_migrate_mm_wq. */ struct cpuset_migrate_mm_work { struct work_struct work; struct mm_struct *mm; nodemask_t from; nodemask_t to; }; static void cpuset_migrate_mm_workfn(struct work_struct *work) { struct cpuset_migrate_mm_work *mwork = container_of(work, struct cpuset_migrate_mm_work, work); /* on a wq worker, no need to worry about %current's mems_allowed */ do_migrate_pages(mwork->mm, &mwork->from, &mwork->to, MPOL_MF_MOVE_ALL); mmput(mwork->mm); kfree(mwork); } static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, const nodemask_t *to) { struct cpuset_migrate_mm_work *mwork; if (nodes_equal(*from, *to)) { mmput(mm); return; } mwork = kzalloc(sizeof(*mwork), GFP_KERNEL); if (mwork) { mwork->mm = mm; mwork->from = *from; mwork->to = *to; INIT_WORK(&mwork->work, cpuset_migrate_mm_workfn); queue_work(cpuset_migrate_mm_wq, &mwork->work); } else { mmput(mm); } } static void cpuset_post_attach(void) { flush_workqueue(cpuset_migrate_mm_wq); } /* * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy * @tsk: the task to change * @newmems: new nodes that the task will be set * * We use the mems_allowed_seq seqlock to safely update both tsk->mems_allowed * and rebind an eventual tasks' mempolicy. If the task is allocating in * parallel, it might temporarily see an empty intersection, which results in * a seqlock check and retry before OOM or allocation failure. */ static void cpuset_change_task_nodemask(struct task_struct *tsk, nodemask_t *newmems) { task_lock(tsk); local_irq_disable(); write_seqcount_begin(&tsk->mems_allowed_seq); nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems); mpol_rebind_task(tsk, newmems); tsk->mems_allowed = *newmems; write_seqcount_end(&tsk->mems_allowed_seq); local_irq_enable(); task_unlock(tsk); } static void *cpuset_being_rebound; /** * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset. * @cs: the cpuset in which each task's mems_allowed mask needs to be changed * * Iterate through each task of @cs updating its mems_allowed to the * effective cpuset's. As this function is called with cpuset_mutex held, * cpuset membership stays stable. */ static void update_tasks_nodemask(struct cpuset *cs) { static nodemask_t newmems; /* protected by cpuset_mutex */ struct css_task_iter it; struct task_struct *task; cpuset_being_rebound = cs; /* causes mpol_dup() rebind */ guarantee_online_mems(cs, &newmems); /* * The mpol_rebind_mm() call takes mmap_lock, which we couldn't * take while holding tasklist_lock. Forks can happen - the * mpol_dup() cpuset_being_rebound check will catch such forks, * and rebind their vma mempolicies too. Because we still hold * the global cpuset_mutex, we know that no other rebind effort * will be contending for the global variable cpuset_being_rebound. * It's ok if we rebind the same mm twice; mpol_rebind_mm() * is idempotent. Also migrate pages in each mm to new nodes. */ css_task_iter_start(&cs->css, 0, &it); while ((task = css_task_iter_next(&it))) { struct mm_struct *mm; bool migrate; cpuset_change_task_nodemask(task, &newmems); mm = get_task_mm(task); if (!mm) continue; migrate = is_memory_migrate(cs); mpol_rebind_mm(mm, &cs->mems_allowed); if (migrate) cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems); else mmput(mm); } css_task_iter_end(&it); /* * All the tasks' nodemasks have been updated, update * cs->old_mems_allowed. */ cs->old_mems_allowed = newmems; /* We're done rebinding vmas to this cpuset's new mems_allowed. */ cpuset_being_rebound = NULL; } /* * update_nodemasks_hier - Update effective nodemasks and tasks in the subtree * @cs: the cpuset to consider * @new_mems: a temp variable for calculating new effective_mems * * When configured nodemask is changed, the effective nodemasks of this cpuset * and all its descendants need to be updated. * * On legacy hierarchy, effective_mems will be the same with mems_allowed. * * Called with cpuset_mutex held */ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems) { struct cpuset *cp; struct cgroup_subsys_state *pos_css; rcu_read_lock(); cpuset_for_each_descendant_pre(cp, pos_css, cs) { struct cpuset *parent = parent_cs(cp); nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems); /* * If it becomes empty, inherit the effective mask of the * parent, which is guaranteed to have some MEMs. */ if (is_in_v2_mode() && nodes_empty(*new_mems)) *new_mems = parent->effective_mems; /* Skip the whole subtree if the nodemask remains the same. */ if (nodes_equal(*new_mems, cp->effective_mems)) { pos_css = css_rightmost_descendant(pos_css); continue; } if (!css_tryget_online(&cp->css)) continue; rcu_read_unlock(); spin_lock_irq(&callback_lock); cp->effective_mems = *new_mems; spin_unlock_irq(&callback_lock); WARN_ON(!is_in_v2_mode() && !nodes_equal(cp->mems_allowed, cp->effective_mems)); update_tasks_nodemask(cp); rcu_read_lock(); css_put(&cp->css); } rcu_read_unlock(); } /* * Handle user request to change the 'mems' memory placement * of a cpuset. Needs to validate the request, update the * cpusets mems_allowed, and for each task in the cpuset, * update mems_allowed and rebind task's mempolicy and any vma * mempolicies and if the cpuset is marked 'memory_migrate', * migrate the tasks pages to the new memory. * * Call with cpuset_mutex held. May take callback_lock during call. * Will take tasklist_lock, scan tasklist for tasks in cpuset cs, * lock each such tasks mm->mmap_lock, scan its vma's and rebind * their mempolicies to the cpusets new mems_allowed. */ static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs, const char *buf) { int retval; /* * top_cpuset.mems_allowed tracks node_stats[N_MEMORY]; * it's read-only */ if (cs == &top_cpuset) { retval = -EACCES; goto done; } /* * An empty mems_allowed is ok iff there are no tasks in the cpuset. * Since nodelist_parse() fails on an empty mask, we special case * that parsing. The validate_change() call ensures that cpusets * with tasks have memory. */ if (!*buf) { nodes_clear(trialcs->mems_allowed); } else { retval = nodelist_parse(buf, trialcs->mems_allowed); if (retval < 0) goto done; if (!nodes_subset(trialcs->mems_allowed, top_cpuset.mems_allowed)) { retval = -EINVAL; goto done; } } if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) { retval = 0; /* Too easy - nothing to do */ goto done; } retval = validate_change(cs, trialcs); if (retval < 0) goto done; check_insane_mems_config(&trialcs->mems_allowed); spin_lock_irq(&callback_lock); cs->mems_allowed = trialcs->mems_allowed; spin_unlock_irq(&callback_lock); /* use trialcs->mems_allowed as a temp variable */ update_nodemasks_hier(cs, &trialcs->mems_allowed); done: return retval; } bool current_cpuset_is_being_rebound(void) { bool ret; rcu_read_lock(); ret = task_cs(current) == cpuset_being_rebound; rcu_read_unlock(); return ret; } static int update_relax_domain_level(struct cpuset *cs, s64 val) { #ifdef CONFIG_SMP if (val < -1 || val >= sched_domain_level_max) return -EINVAL; #endif if (val != cs->relax_domain_level) { cs->relax_domain_level = val; if (!cpumask_empty(cs->cpus_allowed) && is_sched_load_balance(cs)) rebuild_sched_domains_locked(); } return 0; } /** * update_tasks_flags - update the spread flags of tasks in the cpuset. * @cs: the cpuset in which each task's spread flags needs to be changed * * Iterate through each task of @cs updating its spread flags. As this * function is called with cpuset_mutex held, cpuset membership stays * stable. */ static void update_tasks_flags(struct cpuset *cs) { struct css_task_iter it; struct task_struct *task; css_task_iter_start(&cs->css, 0, &it); while ((task = css_task_iter_next(&it))) cpuset_update_task_spread_flags(cs, task); css_task_iter_end(&it); } /* * update_flag - read a 0 or a 1 in a file and update associated flag * bit: the bit to update (see cpuset_flagbits_t) * cs: the cpuset to update * turning_on: whether the flag is being set or cleared * * Call with cpuset_mutex held. */ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, int turning_on) { struct cpuset *trialcs; int balance_flag_changed; int spread_flag_changed; int err; trialcs = alloc_trial_cpuset(cs); if (!trialcs) return -ENOMEM; if (turning_on) set_bit(bit, &trialcs->flags); else clear_bit(bit, &trialcs->flags); err = validate_change(cs, trialcs); if (err < 0) goto out; balance_flag_changed = (is_sched_load_balance(cs) != is_sched_load_balance(trialcs)); spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs)) || (is_spread_page(cs) != is_spread_page(trialcs))); spin_lock_irq(&callback_lock); cs->flags = trialcs->flags; spin_unlock_irq(&callback_lock); if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed) rebuild_sched_domains_locked(); if (spread_flag_changed) update_tasks_flags(cs); out: free_cpuset(trialcs); return err; } /** * update_prstate - update partition_root_state * @cs: the cpuset to update * @new_prs: new partition root state * Return: 0 if successful, != 0 if error * * Call with cpuset_mutex held. */ static int update_prstate(struct cpuset *cs, int new_prs) { int err = PERR_NONE, old_prs = cs->partition_root_state; struct cpuset *parent = parent_cs(cs); struct tmpmasks tmpmask; bool new_xcpus_state = false; if (old_prs == new_prs) return 0; /* * Treat a previously invalid partition root as if it is a "member". */ if (new_prs && is_prs_invalid(old_prs)) old_prs = PRS_MEMBER; if (alloc_cpumasks(NULL, &tmpmask)) return -ENOMEM; /* * Setup effective_xcpus if not properly set yet, it will be cleared * later if partition becomes invalid. */ if ((new_prs > 0) && cpumask_empty(cs->exclusive_cpus)) { spin_lock_irq(&callback_lock); cpumask_and(cs->effective_xcpus, cs->cpus_allowed, parent->effective_xcpus); spin_unlock_irq(&callback_lock); } err = update_partition_exclusive(cs, new_prs); if (err) goto out; if (!old_prs) { enum partition_cmd cmd = (new_prs == PRS_ROOT) ? partcmd_enable : partcmd_enablei; /* * cpus_allowed cannot be empty. */ if (cpumask_empty(cs->cpus_allowed)) { err = PERR_CPUSEMPTY; goto out; } err = update_parent_effective_cpumask(cs, cmd, NULL, &tmpmask); /* * If an attempt to become local partition root fails, * try to become a remote partition root instead. */ if (err && remote_partition_enable(cs, new_prs, &tmpmask)) err = 0; } else if (old_prs && new_prs) { /* * A change in load balance state only, no change in cpumasks. */ new_xcpus_state = true; } else { /* * Switching back to member is always allowed even if it * disables child partitions. */ if (is_remote_partition(cs)) remote_partition_disable(cs, &tmpmask); else update_parent_effective_cpumask(cs, partcmd_disable, NULL, &tmpmask); /* * Invalidation of child partitions will be done in * update_cpumasks_hier(). */ } out: /* * Make partition invalid & disable CS_CPU_EXCLUSIVE if an error * happens. */ if (err) { new_prs = -new_prs; update_partition_exclusive(cs, new_prs); } spin_lock_irq(&callback_lock); cs->partition_root_state = new_prs; WRITE_ONCE(cs->prs_err, err); if (!is_partition_valid(cs)) reset_partition_data(cs); else if (new_xcpus_state) partition_xcpus_newstate(old_prs, new_prs, cs->effective_xcpus); spin_unlock_irq(&callback_lock); update_unbound_workqueue_cpumask(new_xcpus_state); /* Force update if switching back to member */ update_cpumasks_hier(cs, &tmpmask, !new_prs ? HIER_CHECKALL : 0); /* Update sched domains and load balance flag */ update_partition_sd_lb(cs, old_prs); notify_partition_change(cs, old_prs); free_cpumasks(NULL, &tmpmask); return 0; } /* * Frequency meter - How fast is some event occurring? * * These routines manage a digitally filtered, constant time based, * event frequency meter. There are four routines: * fmeter_init() - initialize a frequency meter. * fmeter_markevent() - called each time the event happens. * fmeter_getrate() - returns the recent rate of such events. * fmeter_update() - internal routine used to update fmeter. * * A common data structure is passed to each of these routines, * which is used to keep track of the state required to manage the * frequency meter and its digital filter. * * The filter works on the number of events marked per unit time. * The filter is single-pole low-pass recursive (IIR). The time unit * is 1 second. Arithmetic is done using 32-bit integers scaled to * simulate 3 decimal digits of precision (multiplied by 1000). * * With an FM_COEF of 933, and a time base of 1 second, the filter * has a half-life of 10 seconds, meaning that if the events quit * happening, then the rate returned from the fmeter_getrate() * will be cut in half each 10 seconds, until it converges to zero. * * It is not worth doing a real infinitely recursive filter. If more * than FM_MAXTICKS ticks have elapsed since the last filter event, * just compute FM_MAXTICKS ticks worth, by which point the level * will be stable. * * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid * arithmetic overflow in the fmeter_update() routine. * * Given the simple 32 bit integer arithmetic used, this meter works * best for reporting rates between one per millisecond (msec) and * one per 32 (approx) seconds. At constant rates faster than one * per msec it maxes out at values just under 1,000,000. At constant * rates between one per msec, and one per second it will stabilize * to a value N*1000, where N is the rate of events per second. * At constant rates between one per second and one per 32 seconds, * it will be choppy, moving up on the seconds that have an event, * and then decaying until the next event. At rates slower than * about one in 32 seconds, it decays all the way back to zero between * each event. */ #define FM_COEF 933 /* coefficient for half-life of 10 secs */ #define FM_MAXTICKS ((u32)99) /* useless computing more ticks than this */ #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */ #define FM_SCALE 1000 /* faux fixed point scale */ /* Initialize a frequency meter */ static void fmeter_init(struct fmeter *fmp) { fmp->cnt = 0; fmp->val = 0; fmp->time = 0; spin_lock_init(&fmp->lock); } /* Internal meter update - process cnt events and update value */ static void fmeter_update(struct fmeter *fmp) { time64_t now; u32 ticks; now = ktime_get_seconds(); ticks = now - fmp->time; if (ticks == 0) return; ticks = min(FM_MAXTICKS, ticks); while (ticks-- > 0) fmp->val = (FM_COEF * fmp->val) / FM_SCALE; fmp->time = now; fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE; fmp->cnt = 0; } /* Process any previous ticks, then bump cnt by one (times scale). */ static void fmeter_markevent(struct fmeter *fmp) { spin_lock(&fmp->lock); fmeter_update(fmp); fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE); spin_unlock(&fmp->lock); } /* Process any previous ticks, then return current value. */ static int fmeter_getrate(struct fmeter *fmp) { int val; spin_lock(&fmp->lock); fmeter_update(fmp); val = fmp->val; spin_unlock(&fmp->lock); return val; } static struct cpuset *cpuset_attach_old_cs; /* * Check to see if a cpuset can accept a new task * For v1, cpus_allowed and mems_allowed can't be empty. * For v2, effective_cpus can't be empty. * Note that in v1, effective_cpus = cpus_allowed. */ static int cpuset_can_attach_check(struct cpuset *cs) { if (cpumask_empty(cs->effective_cpus) || (!is_in_v2_mode() && nodes_empty(cs->mems_allowed))) return -ENOSPC; return 0; } static void reset_migrate_dl_data(struct cpuset *cs) { cs->nr_migrate_dl_tasks = 0; cs->sum_migrate_dl_bw = 0; } /* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */ static int cpuset_can_attach(struct cgroup_taskset *tset) { struct cgroup_subsys_state *css; struct cpuset *cs, *oldcs; struct task_struct *task; bool cpus_updated, mems_updated; int ret; /* used later by cpuset_attach() */ cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css)); oldcs = cpuset_attach_old_cs; cs = css_cs(css); mutex_lock(&cpuset_mutex); /* Check to see if task is allowed in the cpuset */ ret = cpuset_can_attach_check(cs); if (ret) goto out_unlock; cpus_updated = !cpumask_equal(cs->effective_cpus, oldcs->effective_cpus); mems_updated = !nodes_equal(cs->effective_mems, oldcs->effective_mems); cgroup_taskset_for_each(task, css, tset) { ret = task_can_attach(task); if (ret) goto out_unlock; /* * Skip rights over task check in v2 when nothing changes, * migration permission derives from hierarchy ownership in * cgroup_procs_write_permission()). */ if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || (cpus_updated || mems_updated)) { ret = security_task_setscheduler(task); if (ret) goto out_unlock; } if (dl_task(task)) { cs->nr_migrate_dl_tasks++; cs->sum_migrate_dl_bw += task->dl.dl_bw; } } if (!cs->nr_migrate_dl_tasks) goto out_success; if (!cpumask_intersects(oldcs->effective_cpus, cs->effective_cpus)) { int cpu = cpumask_any_and(cpu_active_mask, cs->effective_cpus); if (unlikely(cpu >= nr_cpu_ids)) { reset_migrate_dl_data(cs); ret = -EINVAL; goto out_unlock; } ret = dl_bw_alloc(cpu, cs->sum_migrate_dl_bw); if (ret) { reset_migrate_dl_data(cs); goto out_unlock; } } out_success: /* * Mark attach is in progress. This makes validate_change() fail * changes which zero cpus/mems_allowed. */ cs->attach_in_progress++; out_unlock: mutex_unlock(&cpuset_mutex); return ret; } static void cpuset_cancel_attach(struct cgroup_taskset *tset) { struct cgroup_subsys_state *css; struct cpuset *cs; cgroup_taskset_first(tset, &css); cs = css_cs(css); mutex_lock(&cpuset_mutex); cs->attach_in_progress--; if (!cs->attach_in_progress) wake_up(&cpuset_attach_wq); if (cs->nr_migrate_dl_tasks) { int cpu = cpumask_any(cs->effective_cpus); dl_bw_free(cpu, cs->sum_migrate_dl_bw); reset_migrate_dl_data(cs); } mutex_unlock(&cpuset_mutex); } /* * Protected by cpuset_mutex. cpus_attach is used only by cpuset_attach_task() * but we can't allocate it dynamically there. Define it global and * allocate from cpuset_init(). */ static cpumask_var_t cpus_attach; static nodemask_t cpuset_attach_nodemask_to; static void cpuset_attach_task(struct cpuset *cs, struct task_struct *task) { lockdep_assert_held(&cpuset_mutex); if (cs != &top_cpuset) guarantee_online_cpus(task, cpus_attach); else cpumask_andnot(cpus_attach, task_cpu_possible_mask(task), subpartitions_cpus); /* * can_attach beforehand should guarantee that this doesn't * fail. TODO: have a better way to handle failure here */ WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach)); cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to); cpuset_update_task_spread_flags(cs, task); } static void cpuset_attach(struct cgroup_taskset *tset) { struct task_struct *task; struct task_struct *leader; struct cgroup_subsys_state *css; struct cpuset *cs; struct cpuset *oldcs = cpuset_attach_old_cs; bool cpus_updated, mems_updated; cgroup_taskset_first(tset, &css); cs = css_cs(css); lockdep_assert_cpus_held(); /* see cgroup_attach_lock() */ mutex_lock(&cpuset_mutex); cpus_updated = !cpumask_equal(cs->effective_cpus, oldcs->effective_cpus); mems_updated = !nodes_equal(cs->effective_mems, oldcs->effective_mems); /* * In the default hierarchy, enabling cpuset in the child cgroups * will trigger a number of cpuset_attach() calls with no change * in effective cpus and mems. In that case, we can optimize out * by skipping the task iteration and update. */ if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && !cpus_updated && !mems_updated) { cpuset_attach_nodemask_to = cs->effective_mems; goto out; } guarantee_online_mems(cs, &cpuset_attach_nodemask_to); cgroup_taskset_for_each(task, css, tset) cpuset_attach_task(cs, task); /* * Change mm for all threadgroup leaders. This is expensive and may * sleep and should be moved outside migration path proper. Skip it * if there is no change in effective_mems and CS_MEMORY_MIGRATE is * not set. */ cpuset_attach_nodemask_to = cs->effective_mems; if (!is_memory_migrate(cs) && !mems_updated) goto out; cgroup_taskset_for_each_leader(leader, css, tset) { struct mm_struct *mm = get_task_mm(leader); if (mm) { mpol_rebind_mm(mm, &cpuset_attach_nodemask_to); /* * old_mems_allowed is the same with mems_allowed * here, except if this task is being moved * automatically due to hotplug. In that case * @mems_allowed has been updated and is empty, so * @old_mems_allowed is the right nodesets that we * migrate mm from. */ if (is_memory_migrate(cs)) cpuset_migrate_mm(mm, &oldcs->old_mems_allowed, &cpuset_attach_nodemask_to); else mmput(mm); } } out: cs->old_mems_allowed = cpuset_attach_nodemask_to; if (cs->nr_migrate_dl_tasks) { cs->nr_deadline_tasks += cs->nr_migrate_dl_tasks; oldcs->nr_deadline_tasks -= cs->nr_migrate_dl_tasks; reset_migrate_dl_data(cs); } cs->attach_in_progress--; if (!cs->attach_in_progress) wake_up(&cpuset_attach_wq); mutex_unlock(&cpuset_mutex); } /* The various types of files and directories in a cpuset file system */ typedef enum { FILE_MEMORY_MIGRATE, FILE_CPULIST, FILE_MEMLIST, FILE_EFFECTIVE_CPULIST, FILE_EFFECTIVE_MEMLIST, FILE_SUBPARTS_CPULIST, FILE_EXCLUSIVE_CPULIST, FILE_EFFECTIVE_XCPULIST, FILE_ISOLATED_CPULIST, FILE_CPU_EXCLUSIVE, FILE_MEM_EXCLUSIVE, FILE_MEM_HARDWALL, FILE_SCHED_LOAD_BALANCE, FILE_PARTITION_ROOT, FILE_SCHED_RELAX_DOMAIN_LEVEL, FILE_MEMORY_PRESSURE_ENABLED, FILE_MEMORY_PRESSURE, FILE_SPREAD_PAGE, FILE_SPREAD_SLAB, } cpuset_filetype_t; static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft, u64 val) { struct cpuset *cs = css_cs(css); cpuset_filetype_t type = cft->private; int retval = 0; cpus_read_lock(); mutex_lock(&cpuset_mutex); if (!is_cpuset_online(cs)) { retval = -ENODEV; goto out_unlock; } switch (type) { case FILE_CPU_EXCLUSIVE: retval = update_flag(CS_CPU_EXCLUSIVE, cs, val); break; case FILE_MEM_EXCLUSIVE: retval = update_flag(CS_MEM_EXCLUSIVE, cs, val); break; case FILE_MEM_HARDWALL: retval = update_flag(CS_MEM_HARDWALL, cs, val); break; case FILE_SCHED_LOAD_BALANCE: retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val); break; case FILE_MEMORY_MIGRATE: retval = update_flag(CS_MEMORY_MIGRATE, cs, val); break; case FILE_MEMORY_PRESSURE_ENABLED: cpuset_memory_pressure_enabled = !!val; break; case FILE_SPREAD_PAGE: retval = update_flag(CS_SPREAD_PAGE, cs, val); break; case FILE_SPREAD_SLAB: retval = update_flag(CS_SPREAD_SLAB, cs, val); break; default: retval = -EINVAL; break; } out_unlock: mutex_unlock(&cpuset_mutex); cpus_read_unlock(); return retval; } static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft, s64 val) { struct cpuset *cs = css_cs(css); cpuset_filetype_t type = cft->private; int retval = -ENODEV; cpus_read_lock(); mutex_lock(&cpuset_mutex); if (!is_cpuset_online(cs)) goto out_unlock; switch (type) { case FILE_SCHED_RELAX_DOMAIN_LEVEL: retval = update_relax_domain_level(cs, val); break; default: retval = -EINVAL; break; } out_unlock: mutex_unlock(&cpuset_mutex); cpus_read_unlock(); return retval; } /* * Common handling for a write to a "cpus" or "mems" file. */ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { struct cpuset *cs = css_cs(of_css(of)); struct cpuset *trialcs; int retval = -ENODEV; buf = strstrip(buf); /* * CPU or memory hotunplug may leave @cs w/o any execution * resources, in which case the hotplug code asynchronously updates * configuration and transfers all tasks to the nearest ancestor * which can execute. * * As writes to "cpus" or "mems" may restore @cs's execution * resources, wait for the previously scheduled operations before * proceeding, so that we don't end up keep removing tasks added * after execution capability is restored. * * cpuset_hotplug_work calls back into cgroup core via * cgroup_transfer_tasks() and waiting for it from a cgroupfs * operation like this one can lead to a deadlock through kernfs * active_ref protection. Let's break the protection. Losing the * protection is okay as we check whether @cs is online after * grabbing cpuset_mutex anyway. This only happens on the legacy * hierarchies. */ css_get(&cs->css); kernfs_break_active_protection(of->kn); flush_work(&cpuset_hotplug_work); cpus_read_lock(); mutex_lock(&cpuset_mutex); if (!is_cpuset_online(cs)) goto out_unlock; trialcs = alloc_trial_cpuset(cs); if (!trialcs) { retval = -ENOMEM; goto out_unlock; } switch (of_cft(of)->private) { case FILE_CPULIST: retval = update_cpumask(cs, trialcs, buf); break; case FILE_EXCLUSIVE_CPULIST: retval = update_exclusive_cpumask(cs, trialcs, buf); break; case FILE_MEMLIST: retval = update_nodemask(cs, trialcs, buf); break; default: retval = -EINVAL; break; } free_cpuset(trialcs); out_unlock: mutex_unlock(&cpuset_mutex); cpus_read_unlock(); kernfs_unbreak_active_protection(of->kn); css_put(&cs->css); flush_workqueue(cpuset_migrate_mm_wq); return retval ?: nbytes; } /* * These ascii lists should be read in a single call, by using a user * buffer large enough to hold the entire map. If read in smaller * chunks, there is no guarantee of atomicity. Since the display format * used, list of ranges of sequential numbers, is variable length, * and since these maps can change value dynamically, one could read * gibberish by doing partial reads while a list was changing. */ static int cpuset_common_seq_show(struct seq_file *sf, void *v) { struct cpuset *cs = css_cs(seq_css(sf)); cpuset_filetype_t type = seq_cft(sf)->private; int ret = 0; spin_lock_irq(&callback_lock); switch (type) { case FILE_CPULIST: seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->cpus_allowed)); break; case FILE_MEMLIST: seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->mems_allowed)); break; case FILE_EFFECTIVE_CPULIST: seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->effective_cpus)); break; case FILE_EFFECTIVE_MEMLIST: seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->effective_mems)); break; case FILE_EXCLUSIVE_CPULIST: seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->exclusive_cpus)); break; case FILE_EFFECTIVE_XCPULIST: seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->effective_xcpus)); break; case FILE_SUBPARTS_CPULIST: seq_printf(sf, "%*pbl\n", cpumask_pr_args(subpartitions_cpus)); break; case FILE_ISOLATED_CPULIST: seq_printf(sf, "%*pbl\n", cpumask_pr_args(isolated_cpus)); break; default: ret = -EINVAL; } spin_unlock_irq(&callback_lock); return ret; } static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft) { struct cpuset *cs = css_cs(css); cpuset_filetype_t type = cft->private; switch (type) { case FILE_CPU_EXCLUSIVE: return is_cpu_exclusive(cs); case FILE_MEM_EXCLUSIVE: return is_mem_exclusive(cs); case FILE_MEM_HARDWALL: return is_mem_hardwall(cs); case FILE_SCHED_LOAD_BALANCE: return is_sched_load_balance(cs); case FILE_MEMORY_MIGRATE: return is_memory_migrate(cs); case FILE_MEMORY_PRESSURE_ENABLED: return cpuset_memory_pressure_enabled; case FILE_MEMORY_PRESSURE: return fmeter_getrate(&cs->fmeter); case FILE_SPREAD_PAGE: return is_spread_page(cs); case FILE_SPREAD_SLAB: return is_spread_slab(cs); default: BUG(); } /* Unreachable but makes gcc happy */ return 0; } static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft) { struct cpuset *cs = css_cs(css); cpuset_filetype_t type = cft->private; switch (type) { case FILE_SCHED_RELAX_DOMAIN_LEVEL: return cs->relax_domain_level; default: BUG(); } /* Unreachable but makes gcc happy */ return 0; } static int sched_partition_show(struct seq_file *seq, void *v) { struct cpuset *cs = css_cs(seq_css(seq)); const char *err, *type = NULL; switch (cs->partition_root_state) { case PRS_ROOT: seq_puts(seq, "root\n"); break; case PRS_ISOLATED: seq_puts(seq, "isolated\n"); break; case PRS_MEMBER: seq_puts(seq, "member\n"); break; case PRS_INVALID_ROOT: type = "root"; fallthrough; case PRS_INVALID_ISOLATED: if (!type) type = "isolated"; err = perr_strings[READ_ONCE(cs->prs_err)]; if (err) seq_printf(seq, "%s invalid (%s)\n", type, err); else seq_printf(seq, "%s invalid\n", type); break; } return 0; } static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { struct cpuset *cs = css_cs(of_css(of)); int val; int retval = -ENODEV; buf = strstrip(buf); /* * Convert "root" to ENABLED, and convert "member" to DISABLED. */ if (!strcmp(buf, "root")) val = PRS_ROOT; else if (!strcmp(buf, "member")) val = PRS_MEMBER; else if (!strcmp(buf, "isolated")) val = PRS_ISOLATED; else return -EINVAL; css_get(&cs->css); cpus_read_lock(); mutex_lock(&cpuset_mutex); if (!is_cpuset_online(cs)) goto out_unlock; retval = update_prstate(cs, val); out_unlock: mutex_unlock(&cpuset_mutex); cpus_read_unlock(); css_put(&cs->css); return retval ?: nbytes; } /* * for the common functions, 'private' gives the type of file */ static struct cftype legacy_files[] = { { .name = "cpus", .seq_show = cpuset_common_seq_show, .write = cpuset_write_resmask, .max_write_len = (100U + 6 * NR_CPUS), .private = FILE_CPULIST, }, { .name = "mems", .seq_show = cpuset_common_seq_show, .write = cpuset_write_resmask, .max_write_len = (100U + 6 * MAX_NUMNODES), .private = FILE_MEMLIST, }, { .name = "effective_cpus", .seq_show = cpuset_common_seq_show, .private = FILE_EFFECTIVE_CPULIST, }, { .name = "effective_mems", .seq_show = cpuset_common_seq_show, .private = FILE_EFFECTIVE_MEMLIST, }, { .name = "cpu_exclusive", .read_u64 = cpuset_read_u64, .write_u64 = cpuset_write_u64, .private = FILE_CPU_EXCLUSIVE, }, { .name = "mem_exclusive", .read_u64 = cpuset_read_u64, .write_u64 = cpuset_write_u64, .private = FILE_MEM_EXCLUSIVE, }, { .name = "mem_hardwall", .read_u64 = cpuset_read_u64, .write_u64 = cpuset_write_u64, .private = FILE_MEM_HARDWALL, }, { .name = "sched_load_balance", .read_u64 = cpuset_read_u64, .write_u64 = cpuset_write_u64, .private = FILE_SCHED_LOAD_BALANCE, }, { .name = "sched_relax_domain_level", .read_s64 = cpuset_read_s64, .write_s64 = cpuset_write_s64, .private = FILE_SCHED_RELAX_DOMAIN_LEVEL, }, { .name = "memory_migrate", .read_u64 = cpuset_read_u64, .write_u64 = cpuset_write_u64, .private = FILE_MEMORY_MIGRATE, }, { .name = "memory_pressure", .read_u64 = cpuset_read_u64, .private = FILE_MEMORY_PRESSURE, }, { .name = "memory_spread_page", .read_u64 = cpuset_read_u64, .write_u64 = cpuset_write_u64, .private = FILE_SPREAD_PAGE, }, { /* obsolete, may be removed in the future */ .name = "memory_spread_slab", .read_u64 = cpuset_read_u64, .write_u64 = cpuset_write_u64, .private = FILE_SPREAD_SLAB, }, { .name = "memory_pressure_enabled", .flags = CFTYPE_ONLY_ON_ROOT, .read_u64 = cpuset_read_u64, .write_u64 = cpuset_write_u64, .private = FILE_MEMORY_PRESSURE_ENABLED, }, { } /* terminate */ }; /* * This is currently a minimal set for the default hierarchy. It can be * expanded later on by migrating more features and control files from v1. */ static struct cftype dfl_files[] = { { .name = "cpus", .seq_show = cpuset_common_seq_show, .write = cpuset_write_resmask, .max_write_len = (100U + 6 * NR_CPUS), .private = FILE_CPULIST, .flags = CFTYPE_NOT_ON_ROOT, }, { .name = "mems", .seq_show = cpuset_common_seq_show, .write = cpuset_write_resmask, .max_write_len = (100U + 6 * MAX_NUMNODES), .private = FILE_MEMLIST, .flags = CFTYPE_NOT_ON_ROOT, }, { .name = "cpus.effective", .seq_show = cpuset_common_seq_show, .private = FILE_EFFECTIVE_CPULIST, }, { .name = "mems.effective", .seq_show = cpuset_common_seq_show, .private = FILE_EFFECTIVE_MEMLIST, }, { .name = "cpus.partition", .seq_show = sched_partition_show, .write = sched_partition_write, .private = FILE_PARTITION_ROOT, .flags = CFTYPE_NOT_ON_ROOT, .file_offset = offsetof(struct cpuset, partition_file), }, { .name = "cpus.exclusive", .seq_show = cpuset_common_seq_show, .write = cpuset_write_resmask, .max_write_len = (100U + 6 * NR_CPUS), .private = FILE_EXCLUSIVE_CPULIST, .flags = CFTYPE_NOT_ON_ROOT, }, { .name = "cpus.exclusive.effective", .seq_show = cpuset_common_seq_show, .private = FILE_EFFECTIVE_XCPULIST, .flags = CFTYPE_NOT_ON_ROOT, }, { .name = "cpus.subpartitions", .seq_show = cpuset_common_seq_show, .private = FILE_SUBPARTS_CPULIST, .flags = CFTYPE_ONLY_ON_ROOT | CFTYPE_DEBUG, }, { .name = "cpus.isolated", .seq_show = cpuset_common_seq_show, .private = FILE_ISOLATED_CPULIST, .flags = CFTYPE_ONLY_ON_ROOT, }, { } /* terminate */ }; /** * cpuset_css_alloc - Allocate a cpuset css * @parent_css: Parent css of the control group that the new cpuset will be * part of * Return: cpuset css on success, -ENOMEM on failure. * * Allocate and initialize a new cpuset css, for non-NULL @parent_css, return * top cpuset css otherwise. */ static struct cgroup_subsys_state * cpuset_css_alloc(struct cgroup_subsys_state *parent_css) { struct cpuset *cs; if (!parent_css) return &top_cpuset.css; cs = kzalloc(sizeof(*cs), GFP_KERNEL); if (!cs) return ERR_PTR(-ENOMEM); if (alloc_cpumasks(cs, NULL)) { kfree(cs); return ERR_PTR(-ENOMEM); } __set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); nodes_clear(cs->mems_allowed); nodes_clear(cs->effective_mems); fmeter_init(&cs->fmeter); cs->relax_domain_level = -1; INIT_LIST_HEAD(&cs->remote_sibling); /* Set CS_MEMORY_MIGRATE for default hierarchy */ if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) __set_bit(CS_MEMORY_MIGRATE, &cs->flags); return &cs->css; } static int cpuset_css_online(struct cgroup_subsys_state *css) { struct cpuset *cs = css_cs(css); struct cpuset *parent = parent_cs(cs); struct cpuset *tmp_cs; struct cgroup_subsys_state *pos_css; if (!parent) return 0; cpus_read_lock(); mutex_lock(&cpuset_mutex); set_bit(CS_ONLINE, &cs->flags); if (is_spread_page(parent)) set_bit(CS_SPREAD_PAGE, &cs->flags); if (is_spread_slab(parent)) set_bit(CS_SPREAD_SLAB, &cs->flags); cpuset_inc(); spin_lock_irq(&callback_lock); if (is_in_v2_mode()) { cpumask_copy(cs->effective_cpus, parent->effective_cpus); cs->effective_mems = parent->effective_mems; cs->use_parent_ecpus = true; parent->child_ecpus_count++; /* * Clear CS_SCHED_LOAD_BALANCE if parent is isolated */ if (!is_sched_load_balance(parent)) clear_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); } /* * For v2, clear CS_SCHED_LOAD_BALANCE if parent is isolated */ if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && !is_sched_load_balance(parent)) clear_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); spin_unlock_irq(&callback_lock); if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags)) goto out_unlock; /* * Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is * set. This flag handling is implemented in cgroup core for * historical reasons - the flag may be specified during mount. * * Currently, if any sibling cpusets have exclusive cpus or mem, we * refuse to clone the configuration - thereby refusing the task to * be entered, and as a result refusing the sys_unshare() or * clone() which initiated it. If this becomes a problem for some * users who wish to allow that scenario, then this could be * changed to grant parent->cpus_allowed-sibling_cpus_exclusive * (and likewise for mems) to the new cgroup. */ rcu_read_lock(); cpuset_for_each_child(tmp_cs, pos_css, parent) { if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) { rcu_read_unlock(); goto out_unlock; } } rcu_read_unlock(); spin_lock_irq(&callback_lock); cs->mems_allowed = parent->mems_allowed; cs->effective_mems = parent->mems_allowed; cpumask_copy(cs->cpus_allowed, parent->cpus_allowed); cpumask_copy(cs->effective_cpus, parent->cpus_allowed); spin_unlock_irq(&callback_lock); out_unlock: mutex_unlock(&cpuset_mutex); cpus_read_unlock(); return 0; } /* * If the cpuset being removed has its flag 'sched_load_balance' * enabled, then simulate turning sched_load_balance off, which * will call rebuild_sched_domains_locked(). That is not needed * in the default hierarchy where only changes in partition * will cause repartitioning. * * If the cpuset has the 'sched.partition' flag enabled, simulate * turning 'sched.partition" off. */ static void cpuset_css_offline(struct cgroup_subsys_state *css) { struct cpuset *cs = css_cs(css); cpus_read_lock(); mutex_lock(&cpuset_mutex); if (is_partition_valid(cs)) update_prstate(cs, 0); if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && is_sched_load_balance(cs)) update_flag(CS_SCHED_LOAD_BALANCE, cs, 0); if (cs->use_parent_ecpus) { struct cpuset *parent = parent_cs(cs); cs->use_parent_ecpus = false; parent->child_ecpus_count--; } cpuset_dec(); clear_bit(CS_ONLINE, &cs->flags); mutex_unlock(&cpuset_mutex); cpus_read_unlock(); } static void cpuset_css_free(struct cgroup_subsys_state *css) { struct cpuset *cs = css_cs(css); free_cpuset(cs); } static void cpuset_bind(struct cgroup_subsys_state *root_css) { mutex_lock(&cpuset_mutex); spin_lock_irq(&callback_lock); if (is_in_v2_mode()) { cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask); cpumask_copy(top_cpuset.effective_xcpus, cpu_possible_mask); top_cpuset.mems_allowed = node_possible_map; } else { cpumask_copy(top_cpuset.cpus_allowed, top_cpuset.effective_cpus); top_cpuset.mems_allowed = top_cpuset.effective_mems; } spin_unlock_irq(&callback_lock); mutex_unlock(&cpuset_mutex); } /* * In case the child is cloned into a cpuset different from its parent, * additional checks are done to see if the move is allowed. */ static int cpuset_can_fork(struct task_struct *task, struct css_set *cset) { struct cpuset *cs = css_cs(cset->subsys[cpuset_cgrp_id]); bool same_cs; int ret; rcu_read_lock(); same_cs = (cs == task_cs(current)); rcu_read_unlock(); if (same_cs) return 0; lockdep_assert_held(&cgroup_mutex); mutex_lock(&cpuset_mutex); /* Check to see if task is allowed in the cpuset */ ret = cpuset_can_attach_check(cs); if (ret) goto out_unlock; ret = task_can_attach(task); if (ret) goto out_unlock; ret = security_task_setscheduler(task); if (ret) goto out_unlock; /* * Mark attach is in progress. This makes validate_change() fail * changes which zero cpus/mems_allowed. */ cs->attach_in_progress++; out_unlock: mutex_unlock(&cpuset_mutex); return ret; } static void cpuset_cancel_fork(struct task_struct *task, struct css_set *cset) { struct cpuset *cs = css_cs(cset->subsys[cpuset_cgrp_id]); bool same_cs; rcu_read_lock(); same_cs = (cs == task_cs(current)); rcu_read_unlock(); if (same_cs) return; mutex_lock(&cpuset_mutex); cs->attach_in_progress--; if (!cs->attach_in_progress) wake_up(&cpuset_attach_wq); mutex_unlock(&cpuset_mutex); } /* * Make sure the new task conform to the current state of its parent, * which could have been changed by cpuset just after it inherits the * state from the parent and before it sits on the cgroup's task list. */ static void cpuset_fork(struct task_struct *task) { struct cpuset *cs; bool same_cs; rcu_read_lock(); cs = task_cs(task); same_cs = (cs == task_cs(current)); rcu_read_unlock(); if (same_cs) { if (cs == &top_cpuset) return; set_cpus_allowed_ptr(task, current->cpus_ptr); task->mems_allowed = current->mems_allowed; return; } /* CLONE_INTO_CGROUP */ mutex_lock(&cpuset_mutex); guarantee_online_mems(cs, &cpuset_attach_nodemask_to); cpuset_attach_task(cs, task); cs->attach_in_progress--; if (!cs->attach_in_progress) wake_up(&cpuset_attach_wq); mutex_unlock(&cpuset_mutex); } struct cgroup_subsys cpuset_cgrp_subsys = { .css_alloc = cpuset_css_alloc, .css_online = cpuset_css_online, .css_offline = cpuset_css_offline, .css_free = cpuset_css_free, .can_attach = cpuset_can_attach, .cancel_attach = cpuset_cancel_attach, .attach = cpuset_attach, .post_attach = cpuset_post_attach, .bind = cpuset_bind, .can_fork = cpuset_can_fork, .cancel_fork = cpuset_cancel_fork, .fork = cpuset_fork, .legacy_cftypes = legacy_files, .dfl_cftypes = dfl_files, .early_init = true, .threaded = true, }; /** * cpuset_init - initialize cpusets at system boot * * Description: Initialize top_cpuset **/ int __init cpuset_init(void) { BUG_ON(!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL)); BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL)); BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_xcpus, GFP_KERNEL)); BUG_ON(!alloc_cpumask_var(&top_cpuset.exclusive_cpus, GFP_KERNEL)); BUG_ON(!zalloc_cpumask_var(&subpartitions_cpus, GFP_KERNEL)); BUG_ON(!zalloc_cpumask_var(&isolated_cpus, GFP_KERNEL)); cpumask_setall(top_cpuset.cpus_allowed); nodes_setall(top_cpuset.mems_allowed); cpumask_setall(top_cpuset.effective_cpus); cpumask_setall(top_cpuset.effective_xcpus); cpumask_setall(top_cpuset.exclusive_cpus); nodes_setall(top_cpuset.effective_mems); fmeter_init(&top_cpuset.fmeter); set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags); top_cpuset.relax_domain_level = -1; INIT_LIST_HEAD(&remote_children); BUG_ON(!alloc_cpumask_var(&cpus_attach, GFP_KERNEL)); return 0; } /* * If CPU and/or memory hotplug handlers, below, unplug any CPUs * or memory nodes, we need to walk over the cpuset hierarchy, * removing that CPU or node from all cpusets. If this removes the * last CPU or node from a cpuset, then move the tasks in the empty * cpuset to its next-highest non-empty parent. */ static void remove_tasks_in_empty_cpuset(struct cpuset *cs) { struct cpuset *parent; /* * Find its next-highest non-empty parent, (top cpuset * has online cpus, so can't be empty). */ parent = parent_cs(cs); while (cpumask_empty(parent->cpus_allowed) || nodes_empty(parent->mems_allowed)) parent = parent_cs(parent); if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) { pr_err("cpuset: failed to transfer tasks out of empty cpuset "); pr_cont_cgroup_name(cs->css.cgroup); pr_cont("\n"); } } static void hotplug_update_tasks_legacy(struct cpuset *cs, struct cpumask *new_cpus, nodemask_t *new_mems, bool cpus_updated, bool mems_updated) { bool is_empty; spin_lock_irq(&callback_lock); cpumask_copy(cs->cpus_allowed, new_cpus); cpumask_copy(cs->effective_cpus, new_cpus); cs->mems_allowed = *new_mems; cs->effective_mems = *new_mems; spin_unlock_irq(&callback_lock); /* * Don't call update_tasks_cpumask() if the cpuset becomes empty, * as the tasks will be migrated to an ancestor. */ if (cpus_updated && !cpumask_empty(cs->cpus_allowed)) update_tasks_cpumask(cs, new_cpus); if (mems_updated && !nodes_empty(cs->mems_allowed)) update_tasks_nodemask(cs); is_empty = cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed); /* * Move tasks to the nearest ancestor with execution resources, * This is full cgroup operation which will also call back into * cpuset. Should be done outside any lock. */ if (is_empty) { mutex_unlock(&cpuset_mutex); remove_tasks_in_empty_cpuset(cs); mutex_lock(&cpuset_mutex); } } static void hotplug_update_tasks(struct cpuset *cs, struct cpumask *new_cpus, nodemask_t *new_mems, bool cpus_updated, bool mems_updated) { /* A partition root is allowed to have empty effective cpus */ if (cpumask_empty(new_cpus) && !is_partition_valid(cs)) cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus); if (nodes_empty(*new_mems)) *new_mems = parent_cs(cs)->effective_mems; spin_lock_irq(&callback_lock); cpumask_copy(cs->effective_cpus, new_cpus); cs->effective_mems = *new_mems; spin_unlock_irq(&callback_lock); if (cpus_updated) update_tasks_cpumask(cs, new_cpus); if (mems_updated) update_tasks_nodemask(cs); } static bool force_rebuild; void cpuset_force_rebuild(void) { force_rebuild = true; } /* * Attempt to acquire a cpus_read_lock while a hotplug operation may be in * progress. * Return: true if successful, false otherwise * * To avoid circular lock dependency between cpuset_mutex and cpus_read_lock, * cpus_read_trylock() is used here to acquire the lock. */ static bool cpuset_hotplug_cpus_read_trylock(void) { int retries = 0; while (!cpus_read_trylock()) { /* * CPU hotplug still in progress. Retry 5 times * with a 10ms wait before bailing out. */ if (++retries > 5) return false; msleep(10); } return true; } /** * cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug * @cs: cpuset in interest * @tmp: the tmpmasks structure pointer * * Compare @cs's cpu and mem masks against top_cpuset and if some have gone * offline, update @cs accordingly. If @cs ends up with no CPU or memory, * all its tasks are moved to the nearest ancestor with both resources. */ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) { static cpumask_t new_cpus; static nodemask_t new_mems; bool cpus_updated; bool mems_updated; bool remote; int partcmd = -1; struct cpuset *parent; retry: wait_event(cpuset_attach_wq, cs->attach_in_progress == 0); mutex_lock(&cpuset_mutex); /* * We have raced with task attaching. We wait until attaching * is finished, so we won't attach a task to an empty cpuset. */ if (cs->attach_in_progress) { mutex_unlock(&cpuset_mutex); goto retry; } parent = parent_cs(cs); compute_effective_cpumask(&new_cpus, cs, parent); nodes_and(new_mems, cs->mems_allowed, parent->effective_mems); if (!tmp || !cs->partition_root_state) goto update_tasks; /* * Compute effective_cpus for valid partition root, may invalidate * child partition roots if necessary. */ remote = is_remote_partition(cs); if (remote || (is_partition_valid(cs) && is_partition_valid(parent))) compute_partition_effective_cpumask(cs, &new_cpus); if (remote && cpumask_empty(&new_cpus) && partition_is_populated(cs, NULL) && cpuset_hotplug_cpus_read_trylock()) { remote_partition_disable(cs, tmp); compute_effective_cpumask(&new_cpus, cs, parent); remote = false; cpuset_force_rebuild(); cpus_read_unlock(); } /* * Force the partition to become invalid if either one of * the following conditions hold: * 1) empty effective cpus but not valid empty partition. * 2) parent is invalid or doesn't grant any cpus to child * partitions. */ if (is_local_partition(cs) && (!is_partition_valid(parent) || tasks_nocpu_error(parent, cs, &new_cpus))) partcmd = partcmd_invalidate; /* * On the other hand, an invalid partition root may be transitioned * back to a regular one. */ else if (is_partition_valid(parent) && is_partition_invalid(cs)) partcmd = partcmd_update; /* * cpus_read_lock needs to be held before calling * update_parent_effective_cpumask(). To avoid circular lock * dependency between cpuset_mutex and cpus_read_lock, * cpus_read_trylock() is used here to acquire the lock. */ if (partcmd >= 0) { if (!cpuset_hotplug_cpus_read_trylock()) goto update_tasks; update_parent_effective_cpumask(cs, partcmd, NULL, tmp); cpus_read_unlock(); if ((partcmd == partcmd_invalidate) || is_partition_valid(cs)) { compute_partition_effective_cpumask(cs, &new_cpus); cpuset_force_rebuild(); } } update_tasks: cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus); mems_updated = !nodes_equal(new_mems, cs->effective_mems); if (!cpus_updated && !mems_updated) goto unlock; /* Hotplug doesn't affect this cpuset */ if (mems_updated) check_insane_mems_config(&new_mems); if (is_in_v2_mode()) hotplug_update_tasks(cs, &new_cpus, &new_mems, cpus_updated, mems_updated); else hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems, cpus_updated, mems_updated); unlock: mutex_unlock(&cpuset_mutex); } /** * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset * @work: unused * * This function is called after either CPU or memory configuration has * changed and updates cpuset accordingly. The top_cpuset is always * synchronized to cpu_active_mask and N_MEMORY, which is necessary in * order to make cpusets transparent (of no affect) on systems that are * actively using CPU hotplug but making no active use of cpusets. * * Non-root cpusets are only affected by offlining. If any CPUs or memory * nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on * all descendants. * * Note that CPU offlining during suspend is ignored. We don't modify * cpusets across suspend/resume cycles at all. */ static void cpuset_hotplug_workfn(struct work_struct *work) { static cpumask_t new_cpus; static nodemask_t new_mems; bool cpus_updated, mems_updated; bool on_dfl = is_in_v2_mode(); struct tmpmasks tmp, *ptmp = NULL; if (on_dfl && !alloc_cpumasks(NULL, &tmp)) ptmp = &tmp; mutex_lock(&cpuset_mutex); /* fetch the available cpus/mems and find out which changed how */ cpumask_copy(&new_cpus, cpu_active_mask); new_mems = node_states[N_MEMORY]; /* * If subpartitions_cpus is populated, it is likely that the check * below will produce a false positive on cpus_updated when the cpu * list isn't changed. It is extra work, but it is better to be safe. */ cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus) || !cpumask_empty(subpartitions_cpus); mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems); /* * In the rare case that hotplug removes all the cpus in * subpartitions_cpus, we assumed that cpus are updated. */ if (!cpus_updated && top_cpuset.nr_subparts) cpus_updated = true; /* For v1, synchronize cpus_allowed to cpu_active_mask */ if (cpus_updated) { spin_lock_irq(&callback_lock); if (!on_dfl) cpumask_copy(top_cpuset.cpus_allowed, &new_cpus); /* * Make sure that CPUs allocated to child partitions * do not show up in effective_cpus. If no CPU is left, * we clear the subpartitions_cpus & let the child partitions * fight for the CPUs again. */ if (!cpumask_empty(subpartitions_cpus)) { if (cpumask_subset(&new_cpus, subpartitions_cpus)) { top_cpuset.nr_subparts = 0; cpumask_clear(subpartitions_cpus); } else { cpumask_andnot(&new_cpus, &new_cpus, subpartitions_cpus); } } cpumask_copy(top_cpuset.effective_cpus, &new_cpus); spin_unlock_irq(&callback_lock); /* we don't mess with cpumasks of tasks in top_cpuset */ } /* synchronize mems_allowed to N_MEMORY */ if (mems_updated) { spin_lock_irq(&callback_lock); if (!on_dfl) top_cpuset.mems_allowed = new_mems; top_cpuset.effective_mems = new_mems; spin_unlock_irq(&callback_lock); update_tasks_nodemask(&top_cpuset); } mutex_unlock(&cpuset_mutex); /* if cpus or mems changed, we need to propagate to descendants */ if (cpus_updated || mems_updated) { struct cpuset *cs; struct cgroup_subsys_state *pos_css; rcu_read_lock(); cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) { if (cs == &top_cpuset || !css_tryget_online(&cs->css)) continue; rcu_read_unlock(); cpuset_hotplug_update_tasks(cs, ptmp); rcu_read_lock(); css_put(&cs->css); } rcu_read_unlock(); } /* rebuild sched domains if cpus_allowed has changed */ if (cpus_updated || force_rebuild) { force_rebuild = false; rebuild_sched_domains(); } free_cpumasks(NULL, ptmp); } void cpuset_update_active_cpus(void) { /* * We're inside cpu hotplug critical region which usually nests * inside cgroup synchronization. Bounce actual hotplug processing * to a work item to avoid reverse locking order. */ schedule_work(&cpuset_hotplug_work); } void cpuset_wait_for_hotplug(void) { flush_work(&cpuset_hotplug_work); } /* * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY]. * Call this routine anytime after node_states[N_MEMORY] changes. * See cpuset_update_active_cpus() for CPU hotplug handling. */ static int cpuset_track_online_nodes(struct notifier_block *self, unsigned long action, void *arg) { schedule_work(&cpuset_hotplug_work); return NOTIFY_OK; } /** * cpuset_init_smp - initialize cpus_allowed * * Description: Finish top cpuset after cpu, node maps are initialized */ void __init cpuset_init_smp(void) { /* * cpus_allowd/mems_allowed set to v2 values in the initial * cpuset_bind() call will be reset to v1 values in another * cpuset_bind() call when v1 cpuset is mounted. */ top_cpuset.old_mems_allowed = top_cpuset.mems_allowed; cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask); top_cpuset.effective_mems = node_states[N_MEMORY]; hotplug_memory_notifier(cpuset_track_online_nodes, CPUSET_CALLBACK_PRI); cpuset_migrate_mm_wq = alloc_ordered_workqueue("cpuset_migrate_mm", 0); BUG_ON(!cpuset_migrate_mm_wq); } /** * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset. * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed. * @pmask: pointer to struct cpumask variable to receive cpus_allowed set. * * Description: Returns the cpumask_var_t cpus_allowed of the cpuset * attached to the specified @tsk. Guaranteed to return some non-empty * subset of cpu_online_mask, even if this means going outside the * tasks cpuset, except when the task is in the top cpuset. **/ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) { unsigned long flags; struct cpuset *cs; spin_lock_irqsave(&callback_lock, flags); rcu_read_lock(); cs = task_cs(tsk); if (cs != &top_cpuset) guarantee_online_cpus(tsk, pmask); /* * Tasks in the top cpuset won't get update to their cpumasks * when a hotplug online/offline event happens. So we include all * offline cpus in the allowed cpu list. */ if ((cs == &top_cpuset) || cpumask_empty(pmask)) { const struct cpumask *possible_mask = task_cpu_possible_mask(tsk); /* * We first exclude cpus allocated to partitions. If there is no * allowable online cpu left, we fall back to all possible cpus. */ cpumask_andnot(pmask, possible_mask, subpartitions_cpus); if (!cpumask_intersects(pmask, cpu_online_mask)) cpumask_copy(pmask, possible_mask); } rcu_read_unlock(); spin_unlock_irqrestore(&callback_lock, flags); } /** * cpuset_cpus_allowed_fallback - final fallback before complete catastrophe. * @tsk: pointer to task_struct with which the scheduler is struggling * * Description: In the case that the scheduler cannot find an allowed cpu in * tsk->cpus_allowed, we fall back to task_cs(tsk)->cpus_allowed. In legacy * mode however, this value is the same as task_cs(tsk)->effective_cpus, * which will not contain a sane cpumask during cases such as cpu hotplugging. * This is the absolute last resort for the scheduler and it is only used if * _every_ other avenue has been traveled. * * Returns true if the affinity of @tsk was changed, false otherwise. **/ bool cpuset_cpus_allowed_fallback(struct task_struct *tsk) { const struct cpumask *possible_mask = task_cpu_possible_mask(tsk); const struct cpumask *cs_mask; bool changed = false; rcu_read_lock(); cs_mask = task_cs(tsk)->cpus_allowed; if (is_in_v2_mode() && cpumask_subset(cs_mask, possible_mask)) { do_set_cpus_allowed(tsk, cs_mask); changed = true; } rcu_read_unlock(); /* * We own tsk->cpus_allowed, nobody can change it under us. * * But we used cs && cs->cpus_allowed lockless and thus can * race with cgroup_attach_task() or update_cpumask() and get * the wrong tsk->cpus_allowed. However, both cases imply the * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr() * which takes task_rq_lock(). * * If we are called after it dropped the lock we must see all * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary * set any mask even if it is not right from task_cs() pov, * the pending set_cpus_allowed_ptr() will fix things. * * select_fallback_rq() will fix things ups and set cpu_possible_mask * if required. */ return changed; } void __init cpuset_init_current_mems_allowed(void) { nodes_setall(current->mems_allowed); } /** * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset. * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed. * * Description: Returns the nodemask_t mems_allowed of the cpuset * attached to the specified @tsk. Guaranteed to return some non-empty * subset of node_states[N_MEMORY], even if this means going outside the * tasks cpuset. **/ nodemask_t cpuset_mems_allowed(struct task_struct *tsk) { nodemask_t mask; unsigned long flags; spin_lock_irqsave(&callback_lock, flags); rcu_read_lock(); guarantee_online_mems(task_cs(tsk), &mask); rcu_read_unlock(); spin_unlock_irqrestore(&callback_lock, flags); return mask; } /** * cpuset_nodemask_valid_mems_allowed - check nodemask vs. current mems_allowed * @nodemask: the nodemask to be checked * * Are any of the nodes in the nodemask allowed in current->mems_allowed? */ int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask) { return nodes_intersects(*nodemask, current->mems_allowed); } /* * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or * mem_hardwall ancestor to the specified cpuset. Call holding * callback_lock. If no ancestor is mem_exclusive or mem_hardwall * (an unusual configuration), then returns the root cpuset. */ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs) { while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs)) cs = parent_cs(cs); return cs; } /* * cpuset_node_allowed - Can we allocate on a memory node? * @node: is this an allowed node? * @gfp_mask: memory allocation flags * * If we're in interrupt, yes, we can always allocate. If @node is set in * current's mems_allowed, yes. If it's not a __GFP_HARDWALL request and this * node is set in the nearest hardwalled cpuset ancestor to current's cpuset, * yes. If current has access to memory reserves as an oom victim, yes. * Otherwise, no. * * GFP_USER allocations are marked with the __GFP_HARDWALL bit, * and do not allow allocations outside the current tasks cpuset * unless the task has been OOM killed. * GFP_KERNEL allocations are not so marked, so can escape to the * nearest enclosing hardwalled ancestor cpuset. * * Scanning up parent cpusets requires callback_lock. The * __alloc_pages() routine only calls here with __GFP_HARDWALL bit * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the * current tasks mems_allowed came up empty on the first pass over * the zonelist. So only GFP_KERNEL allocations, if all nodes in the * cpuset are short of memory, might require taking the callback_lock. * * The first call here from mm/page_alloc:get_page_from_freelist() * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets, * so no allocation on a node outside the cpuset is allowed (unless * in interrupt, of course). * * The second pass through get_page_from_freelist() doesn't even call * here for GFP_ATOMIC calls. For those calls, the __alloc_pages() * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set * in alloc_flags. That logic and the checks below have the combined * affect that: * in_interrupt - any node ok (current task context irrelevant) * GFP_ATOMIC - any node ok * tsk_is_oom_victim - any node ok * GFP_KERNEL - any node in enclosing hardwalled cpuset ok * GFP_USER - only nodes in current tasks mems allowed ok. */ bool cpuset_node_allowed(int node, gfp_t gfp_mask) { struct cpuset *cs; /* current cpuset ancestors */ bool allowed; /* is allocation in zone z allowed? */ unsigned long flags; if (in_interrupt()) return true; if (node_isset(node, current->mems_allowed)) return true; /* * Allow tasks that have access to memory reserves because they have * been OOM killed to get memory anywhere. */ if (unlikely(tsk_is_oom_victim(current))) return true; if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */ return false; if (current->flags & PF_EXITING) /* Let dying task have memory */ return true; /* Not hardwall and node outside mems_allowed: scan up cpusets */ spin_lock_irqsave(&callback_lock, flags); rcu_read_lock(); cs = nearest_hardwall_ancestor(task_cs(current)); allowed = node_isset(node, cs->mems_allowed); rcu_read_unlock(); spin_unlock_irqrestore(&callback_lock, flags); return allowed; } /** * cpuset_spread_node() - On which node to begin search for a page * @rotor: round robin rotor * * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for * tasks in a cpuset with is_spread_page or is_spread_slab set), * and if the memory allocation used cpuset_mem_spread_node() * to determine on which node to start looking, as it will for * certain page cache or slab cache pages such as used for file * system buffers and inode caches, then instead of starting on the * local node to look for a free page, rather spread the starting * node around the tasks mems_allowed nodes. * * We don't have to worry about the returned node being offline * because "it can't happen", and even if it did, it would be ok. * * The routines calling guarantee_online_mems() are careful to * only set nodes in task->mems_allowed that are online. So it * should not be possible for the following code to return an * offline node. But if it did, that would be ok, as this routine * is not returning the node where the allocation must be, only * the node where the search should start. The zonelist passed to * __alloc_pages() will include all nodes. If the slab allocator * is passed an offline node, it will fall back to the local node. * See kmem_cache_alloc_node(). */ static int cpuset_spread_node(int *rotor) { return *rotor = next_node_in(*rotor, current->mems_allowed); } /** * cpuset_mem_spread_node() - On which node to begin search for a file page */ int cpuset_mem_spread_node(void) { if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE) current->cpuset_mem_spread_rotor = node_random(¤t->mems_allowed); return cpuset_spread_node(¤t->cpuset_mem_spread_rotor); } /** * cpuset_slab_spread_node() - On which node to begin search for a slab page */ int cpuset_slab_spread_node(void) { if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE) current->cpuset_slab_spread_rotor = node_random(¤t->mems_allowed); return cpuset_spread_node(¤t->cpuset_slab_spread_rotor); } EXPORT_SYMBOL_GPL(cpuset_mem_spread_node); /** * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's? * @tsk1: pointer to task_struct of some task. * @tsk2: pointer to task_struct of some other task. * * Description: Return true if @tsk1's mems_allowed intersects the * mems_allowed of @tsk2. Used by the OOM killer to determine if * one of the task's memory usage might impact the memory available * to the other. **/ int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, const struct task_struct *tsk2) { return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed); } /** * cpuset_print_current_mems_allowed - prints current's cpuset and mems_allowed * * Description: Prints current's name, cpuset name, and cached copy of its * mems_allowed to the kernel log. */ void cpuset_print_current_mems_allowed(void) { struct cgroup *cgrp; rcu_read_lock(); cgrp = task_cs(current)->css.cgroup; pr_cont(",cpuset="); pr_cont_cgroup_name(cgrp); pr_cont(",mems_allowed=%*pbl", nodemask_pr_args(¤t->mems_allowed)); rcu_read_unlock(); } /* * Collection of memory_pressure is suppressed unless * this flag is enabled by writing "1" to the special * cpuset file 'memory_pressure_enabled' in the root cpuset. */ int cpuset_memory_pressure_enabled __read_mostly; /* * __cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims. * * Keep a running average of the rate of synchronous (direct) * page reclaim efforts initiated by tasks in each cpuset. * * This represents the rate at which some task in the cpuset * ran low on memory on all nodes it was allowed to use, and * had to enter the kernels page reclaim code in an effort to * create more free memory by tossing clean pages or swapping * or writing dirty pages. * * Display to user space in the per-cpuset read-only file * "memory_pressure". Value displayed is an integer * representing the recent rate of entry into the synchronous * (direct) page reclaim by any task attached to the cpuset. */ void __cpuset_memory_pressure_bump(void) { rcu_read_lock(); fmeter_markevent(&task_cs(current)->fmeter); rcu_read_unlock(); } #ifdef CONFIG_PROC_PID_CPUSET /* * proc_cpuset_show() * - Print tasks cpuset path into seq_file. * - Used for /proc/<pid>/cpuset. * - No need to task_lock(tsk) on this tsk->cpuset reference, as it * doesn't really matter if tsk->cpuset changes after we read it, * and we take cpuset_mutex, keeping cpuset_attach() from changing it * anyway. */ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *tsk) { char *buf; struct cgroup_subsys_state *css; int retval; retval = -ENOMEM; buf = kmalloc(PATH_MAX, GFP_KERNEL); if (!buf) goto out; css = task_get_css(tsk, cpuset_cgrp_id); retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX, current->nsproxy->cgroup_ns); css_put(css); if (retval == -E2BIG) retval = -ENAMETOOLONG; if (retval < 0) goto out_free; seq_puts(m, buf); seq_putc(m, '\n'); retval = 0; out_free: kfree(buf); out: return retval; } #endif /* CONFIG_PROC_PID_CPUSET */ /* Display task mems_allowed in /proc/<pid>/status file. */ void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task) { seq_printf(m, "Mems_allowed:\t%*pb\n", nodemask_pr_args(&task->mems_allowed)); seq_printf(m, "Mems_allowed_list:\t%*pbl\n", nodemask_pr_args(&task->mems_allowed)); }
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