Release 4.7 mm/oom_kill.c
/*
* linux/mm/oom_kill.c
*
* Copyright (C) 1998,2000 Rik van Riel
* Thanks go out to Claus Fischer for some serious inspiration and
* for goading me into coding this file...
* Copyright (C) 2010 Google, Inc.
* Rewritten by David Rientjes
*
* The routines in this file are used to kill a process when
* we're seriously out of memory. This gets called from __alloc_pages()
* in mm/page_alloc.c when we really run out of memory.
*
* Since we won't call these routines often (on a well-configured
* machine) this file will double as a 'coding guide' and a signpost
* for newbie kernel hackers. It features several pointers to major
* kernel subsystems and hints as to where to find out what things do.
*/
#include <linux/oom.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/gfp.h>
#include <linux/sched.h>
#include <linux/swap.h>
#include <linux/timex.h>
#include <linux/jiffies.h>
#include <linux/cpuset.h>
#include <linux/export.h>
#include <linux/notifier.h>
#include <linux/memcontrol.h>
#include <linux/mempolicy.h>
#include <linux/security.h>
#include <linux/ptrace.h>
#include <linux/freezer.h>
#include <linux/ftrace.h>
#include <linux/ratelimit.h>
#include <linux/kthread.h>
#include <linux/init.h>
#include <asm/tlb.h>
#include "internal.h"
#define CREATE_TRACE_POINTS
#include <trace/events/oom.h>
int sysctl_panic_on_oom;
int sysctl_oom_kill_allocating_task;
int sysctl_oom_dump_tasks = 1;
DEFINE_MUTEX(oom_lock);
#ifdef CONFIG_NUMA
/**
* has_intersects_mems_allowed() - check task eligiblity for kill
* @start: task struct of which task to consider
* @mask: nodemask passed to page allocator for mempolicy ooms
*
* Task eligibility is determined by whether or not a candidate task, @tsk,
* shares the same mempolicy nodes as current if it is bound by such a policy
* and whether or not it has the same set of allowed cpuset nodes.
*/
static bool has_intersects_mems_allowed(struct task_struct *start,
const nodemask_t *mask)
{
struct task_struct *tsk;
bool ret = false;
rcu_read_lock();
for_each_thread(start, tsk) {
if (mask) {
/*
* If this is a mempolicy constrained oom, tsk's
* cpuset is irrelevant. Only return true if its
* mempolicy intersects current, otherwise it may be
* needlessly killed.
*/
ret = mempolicy_nodemask_intersects(tsk, mask);
} else {
/*
* This is not a mempolicy constrained oom, so only
* check the mems of tsk's cpuset.
*/
ret = cpuset_mems_allowed_intersects(current, tsk);
}
if (ret)
break;
}
rcu_read_unlock();
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| oleg nesterov | oleg nesterov | 31 | 40.26% | 2 | 50.00% |
| david rientjes | david rientjes | 24 | 31.17% | 1 | 25.00% |
| kosaki motohiro | kosaki motohiro | 22 | 28.57% | 1 | 25.00% |
| Total | 77 | 100.00% | 4 | 100.00% |
#else
static bool has_intersects_mems_allowed(struct task_struct *tsk,
const nodemask_t *mask)
{
return true;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 16 | 84.21% | 1 | 33.33% |
| kosaki motohiro | kosaki motohiro | 2 | 10.53% | 1 | 33.33% |
| oleg nesterov | oleg nesterov | 1 | 5.26% | 1 | 33.33% |
| Total | 19 | 100.00% | 3 | 100.00% |
#endif /* CONFIG_NUMA */
/*
* The process p may have detached its own ->mm while exiting or through
* use_mm(), but one or more of its subthreads may still have a valid
* pointer. Return p, or any of its subthreads with a valid ->mm, with
* task_lock() held.
*/
struct task_struct *find_lock_task_mm(struct task_struct *p)
{
struct task_struct *t;
rcu_read_lock();
for_each_thread(p, t) {
task_lock(t);
if (likely(t->mm))
goto found;
task_unlock(t);
}
t = NULL;
found:
rcu_read_unlock();
return t;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| oleg nesterov | oleg nesterov | 62 | 100.00% | 3 | 100.00% |
| Total | 62 | 100.00% | 3 | 100.00% |
/*
* order == -1 means the oom kill is required by sysrq, otherwise only
* for display purposes.
*/
static inline bool is_sysrq_oom(struct oom_control *oc)
{
return oc->order == -1;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| yaowei bai | yaowei bai | 20 | 100.00% | 1 | 100.00% |
| Total | 20 | 100.00% | 1 | 100.00% |
/* return true if the task is not adequate as candidate victim task. */
static bool oom_unkillable_task(struct task_struct *p,
struct mem_cgroup *memcg, const nodemask_t *nodemask)
{
if (is_global_init(p))
return true;
if (p->flags & PF_KTHREAD)
return true;
/* When mem_cgroup_out_of_memory() and p is not member of the group */
if (memcg && !task_in_mem_cgroup(p, memcg))
return true;
/* p may not have freeable memory in nodemask */
if (!has_intersects_mems_allowed(p, nodemask))
return true;
return false;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| kosaki motohiro | kosaki motohiro | 71 | 94.67% | 1 | 33.33% |
| johannes weiner | johannes weiner | 3 | 4.00% | 1 | 33.33% |
| oleg nesterov | oleg nesterov | 1 | 1.33% | 1 | 33.33% |
| Total | 75 | 100.00% | 3 | 100.00% |
/**
* oom_badness - heuristic function to determine which candidate task to kill
* @p: task struct of which task we should calculate
* @totalpages: total present RAM allowed for page allocation
*
* The heuristic for determining which task to kill is made to be as simple and
* predictable as possible. The goal is to return the highest value for the
* task consuming the most memory to avoid subsequent oom failures.
*/
unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
const nodemask_t *nodemask, unsigned long totalpages)
{
long points;
long adj;
if (oom_unkillable_task(p, memcg, nodemask))
return 0;
p = find_lock_task_mm(p);
if (!p)
return 0;
/*
* Do not even consider tasks which are explicitly marked oom
* unkillable or have been already oom reaped.
*/
adj = (long)p->signal->oom_score_adj;
if (adj == OOM_SCORE_ADJ_MIN ||
test_bit(MMF_OOM_REAPED, &p->mm->flags)) {
task_unlock(p);
return 0;
}
/*
* The baseline for the badness score is the proportion of RAM that each
* task's rss, pagetable and swap space use.
*/
points = get_mm_rss(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS) +
atomic_long_read(&p->mm->nr_ptes) + mm_nr_pmds(p->mm);
task_unlock(p);
/*
* Root processes get 3% bonus, just like the __vm_enough_memory()
* implementation used by LSMs.
*/
if (has_capability_noaudit(p, CAP_SYS_ADMIN))
points -= (points * 3) / 100;
/* Normalize to oom_score_adj units */
adj *= totalpages / 1000;
points += adj;
/*
* Never return 0 for an eligible task regardless of the root bonus and
* oom_score_adj (oom_score_adj can't be OOM_SCORE_ADJ_MIN here).
*/
return points > 0 ? points : 1;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 54 | 29.67% | 6 | 23.08% |
| michal hocko | michal hocko | 31 | 17.03% | 2 | 7.69% |
| kosaki motohiro | kosaki motohiro | 31 | 17.03% | 5 | 19.23% |
| pre-git | pre-git | 31 | 17.03% | 1 | 3.85% |
| kirill a. shutemov | kirill a. shutemov | 14 | 7.69% | 2 | 7.69% |
| andrew morton | andrew morton | 6 | 3.30% | 2 | 7.69% |
| oleg nesterov | oleg nesterov | 4 | 2.20% | 1 | 3.85% |
| tim schmielau | tim schmielau | 3 | 1.65% | 1 | 3.85% |
| johannes weiner | johannes weiner | 2 | 1.10% | 1 | 3.85% |
| ingo molnar | ingo molnar | 2 | 1.10% | 1 | 3.85% |
| cyrill gorcunov | cyrill gorcunov | 1 | 0.55% | 1 | 3.85% |
| andrew g. morgan | andrew g. morgan | 1 | 0.55% | 1 | 3.85% |
| frantisek hrbata | frantisek hrbata | 1 | 0.55% | 1 | 3.85% |
| eric paris | eric paris | 1 | 0.55% | 1 | 3.85% |
| Total | 182 | 100.00% | 26 | 100.00% |
/*
* Determine the type of allocation constraint.
*/
#ifdef CONFIG_NUMA
static enum oom_constraint constrained_alloc(struct oom_control *oc,
unsigned long *totalpages)
{
struct zone *zone;
struct zoneref *z;
enum zone_type high_zoneidx = gfp_zone(oc->gfp_mask);
bool cpuset_limited = false;
int nid;
/* Default to all available memory */
*totalpages = totalram_pages + total_swap_pages;
if (!oc->zonelist)
return CONSTRAINT_NONE;
/*
* Reach here only when __GFP_NOFAIL is used. So, we should avoid
* to kill current.We have to random task kill in this case.
* Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now.
*/
if (oc->gfp_mask & __GFP_THISNODE)
return CONSTRAINT_NONE;
/*
* This is not a __GFP_THISNODE allocation, so a truncated nodemask in
* the page allocator means a mempolicy is in effect. Cpuset policy
* is enforced in get_page_from_freelist().
*/
if (oc->nodemask &&
!nodes_subset(node_states[N_MEMORY], *oc->nodemask)) {
*totalpages = total_swap_pages;
for_each_node_mask(nid, *oc->nodemask)
*totalpages += node_spanned_pages(nid);
return CONSTRAINT_MEMORY_POLICY;
}
/* Check this allocation failure is caused by cpuset's wall function */
for_each_zone_zonelist_nodemask(zone, z, oc->zonelist,
high_zoneidx, oc->nodemask)
if (!cpuset_zone_allowed(zone, oc->gfp_mask))
cpuset_limited = true;
if (cpuset_limited) {
*totalpages = total_swap_pages;
for_each_node_mask(nid, cpuset_current_mems_allowed)
*totalpages += node_spanned_pages(nid);
return CONSTRAINT_CPUSET;
}
return CONSTRAINT_NONE;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 102 | 55.43% | 3 | 30.00% |
| kamezawa hiroyuki | kamezawa hiroyuki | 31 | 16.85% | 1 | 10.00% |
| christoph lameter | christoph lameter | 27 | 14.67% | 2 | 20.00% |
| mel gorman | mel gorman | 22 | 11.96% | 2 | 20.00% |
| vladimir davydov | vladimir davydov | 1 | 0.54% | 1 | 10.00% |
| lai jiangshan | lai jiangshan | 1 | 0.54% | 1 | 10.00% |
| Total | 184 | 100.00% | 10 | 100.00% |
#else
static enum oom_constraint constrained_alloc(struct oom_control *oc,
unsigned long *totalpages)
{
*totalpages = totalram_pages + total_swap_pages;
return CONSTRAINT_NONE;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 14 | 51.85% | 2 | 50.00% |
| kamezawa hiroyuki | kamezawa hiroyuki | 9 | 33.33% | 1 | 25.00% |
| christoph lameter | christoph lameter | 4 | 14.81% | 1 | 25.00% |
| Total | 27 | 100.00% | 4 | 100.00% |
#endif
enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
struct task_struct *task, unsigned long totalpages)
{
if (oom_unkillable_task(task, NULL, oc->nodemask))
return OOM_SCAN_CONTINUE;
/*
* This task already has access to memory reserves and is being killed.
* Don't allow any other task to have access to the reserves.
*/
if (!is_sysrq_oom(oc) && atomic_read(&task->signal->oom_victims))
return OOM_SCAN_ABORT;
/*
* If task is allocating a lot of memory and has been marked to be
* killed first if it triggers an oom, then select it.
*/
if (oom_task_origin(task))
return OOM_SCAN_SELECT;
return OOM_SCAN_OK;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 47 | 65.28% | 9 | 56.25% |
| tetsuo handa | tetsuo handa | 9 | 12.50% | 1 | 6.25% |
| pre-git | pre-git | 5 | 6.94% | 1 | 6.25% |
| yaowei bai | yaowei bai | 4 | 5.56% | 1 | 6.25% |
| oleg nesterov | oleg nesterov | 2 | 2.78% | 1 | 6.25% |
| kurt garloff | kurt garloff | 2 | 2.78% | 1 | 6.25% |
| nick piggin | nick piggin | 2 | 2.78% | 1 | 6.25% |
| kosaki motohiro | kosaki motohiro | 1 | 1.39% | 1 | 6.25% |
| Total | 72 | 100.00% | 16 | 100.00% |
/*
* Simple selection loop. We chose the process with the highest
* number of 'points'. Returns -1 on scan abort.
*/
static struct task_struct *select_bad_process(struct oom_control *oc,
unsigned int *ppoints, unsigned long totalpages)
{
struct task_struct *p;
struct task_struct *chosen = NULL;
unsigned long chosen_points = 0;
rcu_read_lock();
for_each_process(p) {
unsigned int points;
switch (oom_scan_process_thread(oc, p, totalpages)) {
case OOM_SCAN_SELECT:
chosen = p;
chosen_points = ULONG_MAX;
/* fall through */
case OOM_SCAN_CONTINUE:
continue;
case OOM_SCAN_ABORT:
rcu_read_unlock();
return (struct task_struct *)(-1UL);
case OOM_SCAN_OK:
break;
};
points = oom_badness(p, NULL, oc->nodemask, totalpages);
if (!points || points < chosen_points)
continue;
chosen = p;
chosen_points = points;
}
if (chosen)
get_task_struct(chosen);
rcu_read_unlock();
*ppoints = chosen_points * 1000 / totalpages;
return chosen;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 127 | 78.88% | 8 | 57.14% |
| pre-git | pre-git | 19 | 11.80% | 1 | 7.14% |
| rusty russell | rusty russell | 7 | 4.35% | 1 | 7.14% |
| kosaki motohiro | kosaki motohiro | 3 | 1.86% | 1 | 7.14% |
| andrea arcangeli | andrea arcangeli | 3 | 1.86% | 1 | 7.14% |
| tetsuo handa | tetsuo handa | 1 | 0.62% | 1 | 7.14% |
| tim schmielau | tim schmielau | 1 | 0.62% | 1 | 7.14% |
| Total | 161 | 100.00% | 14 | 100.00% |
/**
* dump_tasks - dump current memory state of all system tasks
* @memcg: current's memory controller, if constrained
* @nodemask: nodemask passed to page allocator for mempolicy ooms
*
* Dumps the current memory state of all eligible tasks. Tasks not in the same
* memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes
* are not shown.
* State information includes task's pid, uid, tgid, vm size, rss, nr_ptes,
* swapents, oom_score_adj value, and name.
*/
static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask)
{
struct task_struct *p;
struct task_struct *task;
pr_info("[ pid ] uid tgid total_vm rss nr_ptes nr_pmds swapents oom_score_adj name\n");
rcu_read_lock();
for_each_process(p) {
if (oom_unkillable_task(p, memcg, nodemask))
continue;
task = find_lock_task_mm(p);
if (!task) {
/*
* This is a kthread or all of p's threads have already
* detached their mm's. There's no need to report
* them; they can't be oom killed anyway.
*/
continue;
}
pr_info("[%5d] %5d %5d %8lu %8lu %7ld %7ld %8lu %5hd %s\n",
task->pid, from_kuid(&init_user_ns, task_uid(task)),
task->tgid, task->mm->total_vm, get_mm_rss(task->mm),
atomic_long_read(&task->mm->nr_ptes),
mm_nr_pmds(task->mm),
get_mm_counter(task->mm, MM_SWAPENTS),
task->signal->oom_score_adj, task->comm);
task_unlock(task);
}
rcu_read_unlock();
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 104 | 69.80% | 9 | 56.25% |
| kosaki motohiro | kosaki motohiro | 22 | 14.77% | 2 | 12.50% |
| kirill a. shutemov | kirill a. shutemov | 13 | 8.72% | 2 | 12.50% |
| eric w. biederman | eric w. biederman | 6 | 4.03% | 1 | 6.25% |
| johannes weiner | johannes weiner | 2 | 1.34% | 1 | 6.25% |
| david howells | david howells | 2 | 1.34% | 1 | 6.25% |
| Total | 149 | 100.00% | 16 | 100.00% |
static void dump_header(struct oom_control *oc, struct task_struct *p,
struct mem_cgroup *memcg)
{
pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), order=%d, oom_score_adj=%hd\n",
current->comm, oc->gfp_mask, &oc->gfp_mask, oc->order,
current->signal->oom_score_adj);
cpuset_print_current_mems_allowed();
dump_stack();
if (memcg)
mem_cgroup_print_oom_info(memcg, p);
else
show_mem(SHOW_MEM_FILTER_NODES);
if (sysctl_oom_dump_tasks)
dump_tasks(memcg, oc->nodemask);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 64 | 75.29% | 7 | 58.33% |
| vlastimil babka | vlastimil babka | 6 | 7.06% | 1 | 8.33% |
| daisuke nishimura | daisuke nishimura | 6 | 7.06% | 1 | 8.33% |
| sha zhengju | sha zhengju | 5 | 5.88% | 1 | 8.33% |
| johannes weiner | johannes weiner | 3 | 3.53% | 1 | 8.33% |
| joe perches | joe perches | 1 | 1.18% | 1 | 8.33% |
| Total | 85 | 100.00% | 12 | 100.00% |
/*
* Number of OOM victims in flight
*/
static atomic_t oom_victims = ATOMIC_INIT(0);
static DECLARE_WAIT_QUEUE_HEAD(oom_victims_wait);
bool oom_killer_disabled __read_mostly;
#define K(x) ((x) << (PAGE_SHIFT-10))
/*
* task->mm can be NULL if the task is the exited group leader. So to
* determine whether the task is using a particular mm, we examine all the
* task's threads: if one of those is using this mm then this task was also
* using it.
*/
static bool process_shares_mm(struct task_struct *p, struct mm_struct *mm)
{
struct task_struct *t;
for_each_thread(p, t) {
struct mm_struct *t_mm = READ_ONCE(t->mm);
if (t_mm)
return t_mm == mm;
}
return false;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 53 | 100.00% | 1 | 100.00% |
| Total | 53 | 100.00% | 1 | 100.00% |
#ifdef CONFIG_MMU
/*
* OOM Reaper kernel thread which tries to reap the memory used by the OOM
* victim (if that is possible) to help the OOM killer to move on.
*/
static struct task_struct *oom_reaper_th;
static DECLARE_WAIT_QUEUE_HEAD(oom_reaper_wait);
static struct task_struct *oom_reaper_list;
static DEFINE_SPINLOCK(oom_reaper_lock);
static bool __oom_reap_task(struct task_struct *tsk)
{
struct mmu_gather tlb;
struct vm_area_struct *vma;
struct mm_struct *mm = NULL;
struct task_struct *p;
struct zap_details details = {.check_swap_entries = true,
.ignore_dirty = true};
bool ret = true;
/*
* We have to make sure to not race with the victim exit path
* and cause premature new oom victim selection:
* __oom_reap_task exit_mm
* atomic_inc_not_zero
* mmput
* atomic_dec_and_test
* exit_oom_victim
* [...]
* out_of_memory
* select_bad_process
* # no TIF_MEMDIE task selects new victim
* unmap_page_range # frees some memory
*/
mutex_lock(&oom_lock);
/*
* Make sure we find the associated mm_struct even when the particular
* thread has already terminated and cleared its mm.
* We might have race with exit path so consider our work done if there
* is no mm.
*/
p = find_lock_task_mm(tsk);
if (!p)
goto unlock_oom;
mm = p->mm;
atomic_inc(&mm->mm_users);
task_unlock(p);
if (!down_read_trylock(&mm->mmap_sem)) {
ret = false;
goto unlock_oom;
}
tlb_gather_mmu(&tlb, mm, 0, -1);
for (vma = mm->mmap ; vma; vma = vma->vm_next) {
if (is_vm_hugetlb_page(vma))
continue;
/*
* mlocked VMAs require explicit munlocking before unmap.
* Let's keep it simple here and skip such VMAs.
*/
if (vma->vm_flags & VM_LOCKED)
continue;
/*
* Only anonymous pages have a good chance to be dropped
* without additional steps which we cannot afford as we
* are OOM already.
*
* We do not even care about fs backed pages because all
* which are reclaimable have already been reclaimed and
* we do not want to block exit_mmap by keeping mm ref
* count elevated without a good reason.
*/
if (vma_is_anonymous(vma) || !(vma->vm_flags & VM_SHARED))
unmap_page_range(&tlb, vma, vma->vm_start, vma->vm_end,
&details);
}
tlb_finish_mmu(&tlb, 0, -1);
pr_info("oom_reaper: reaped process %d (%s), now anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n",
task_pid_nr(tsk), tsk->comm,
K(get_mm_counter(mm, MM_ANONPAGES)),
K(get_mm_counter(mm, MM_FILEPAGES)),
K(get_mm_counter(mm, MM_SHMEMPAGES)));
up_read(&mm->mmap_sem);
/*
* This task can be safely ignored because we cannot do much more
* to release its memory.
*/
set_bit(MMF_OOM_REAPED, &mm->flags);
unlock_oom:
mutex_unlock(&oom_lock);
/*
* Drop our reference but make sure the mmput slow path is called from a
* different context because we shouldn't risk we get stuck there and
* put the oom_reaper out of the way.
*/
if (mm)
mmput_async(mm);
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 294 | 99.66% | 7 | 87.50% |
| tetsuo handa | tetsuo handa | 1 | 0.34% | 1 | 12.50% |
| Total | 295 | 100.00% | 8 | 100.00% |
#define MAX_OOM_REAP_RETRIES 10
static void oom_reap_task(struct task_struct *tsk)
{
int attempts = 0;
/* Retry the down_read_trylock(mmap_sem) a few times */
while (attempts++ < MAX_OOM_REAP_RETRIES && !__oom_reap_task(tsk))
schedule_timeout_idle(HZ/10);
if (attempts > MAX_OOM_REAP_RETRIES) {
pr_info("oom_reaper: unable to reap pid:%d (%s)\n",
task_pid_nr(tsk), tsk->comm);
debug_show_all_locks();
}
/*
* Clear TIF_MEMDIE because the task shouldn't be sitting on a
* reasonably reclaimable memory anymore or it is not a good candidate
* for the oom victim right now because it cannot release its memory
* itself nor by the oom reaper.
*/
tsk->oom_reaper_list = NULL;
exit_oom_victim(tsk);
/* Drop a reference taken by wake_oom_reaper */
put_task_struct(tsk);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 80 | 100.00% | 4 | 100.00% |
| Total | 80 | 100.00% | 4 | 100.00% |
static int oom_reaper(void *unused)
{
set_freezable();
while (true) {
struct task_struct *tsk = NULL;
wait_event_freezable(oom_reaper_wait, oom_reaper_list != NULL);
spin_lock(&oom_reaper_lock);
if (oom_reaper_list != NULL) {
tsk = oom_reaper_list;
oom_reaper_list = tsk->oom_reaper_list;
}
spin_unlock(&oom_reaper_lock);
if (tsk)
oom_reap_task(tsk);
}
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 71 | 92.21% | 4 | 80.00% |
| vladimir davydov | vladimir davydov | 6 | 7.79% | 1 | 20.00% |
| Total | 77 | 100.00% | 5 | 100.00% |
static void wake_oom_reaper(struct task_struct *tsk)
{
if (!oom_reaper_th)
return;
/* tsk is already queued? */
if (tsk == oom_reaper_list || tsk->oom_reaper_list)
return;
get_task_struct(tsk);
spin_lock(&oom_reaper_lock);
tsk->oom_reaper_list = oom_reaper_list;
oom_reaper_list = tsk;
spin_unlock(&oom_reaper_lock);
wake_up(&oom_reaper_wait);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 53 | 85.48% | 4 | 66.67% |
| vladimir davydov | vladimir davydov | 5 | 8.06% | 1 | 16.67% |
| tetsuo handa | tetsuo handa | 4 | 6.45% | 1 | 16.67% |
| Total | 62 | 100.00% | 6 | 100.00% |
/* Check if we can reap the given task. This has to be called with stable
* tsk->mm
*/
void try_oom_reaper(struct task_struct *tsk)
{
struct mm_struct *mm = tsk->mm;
struct task_struct *p;
if (!mm)
return;
/*
* There might be other threads/processes which are either not
* dying or even not killable.
*/
if (atomic_read(&mm->mm_users) > 1) {
rcu_read_lock();
for_each_process(p) {
if (!process_shares_mm(p, mm))
continue;
if (fatal_signal_pending(p))
continue;
/*
* If the task is exiting make sure the whole thread group
* is exiting and cannot acces mm anymore.
*/
if (signal_group_exit(p->signal))
continue;
/* Give up */
rcu_read_unlock();
return;
}
rcu_read_unlock();
}
wake_oom_reaper(tsk);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 97 | 100.00% | 2 | 100.00% |
| Total | 97 | 100.00% | 2 | 100.00% |
static int __init oom_init(void)
{
oom_reaper_th = kthread_run(oom_reaper, NULL, "oom_reaper");
if (IS_ERR(oom_reaper_th)) {
pr_err("Unable to start OOM reaper %ld. Continuing regardless\n",
PTR_ERR(oom_reaper_th));
oom_reaper_th = NULL;
}
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 46 | 100.00% | 1 | 100.00% |
| Total | 46 | 100.00% | 1 | 100.00% |
subsys_initcall(oom_init)
#else
static void wake_oom_reaper(struct task_struct *tsk)
{
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 10 | 100.00% | 2 | 100.00% |
| Total | 10 | 100.00% | 2 | 100.00% |
#endif
/**
* mark_oom_victim - mark the given task as OOM victim
* @tsk: task to mark
*
* Has to be called with oom_lock held and never after
* oom has been disabled already.
*/
void mark_oom_victim(struct task_struct *tsk)
{
WARN_ON(oom_killer_disabled);
/* OOM killer might race with memcg OOM */
if (test_and_set_tsk_thread_flag(tsk, TIF_MEMDIE))
return;
atomic_inc(&tsk->signal->oom_victims);
/*
* Make sure that the task is woken up from uninterruptible sleep
* if it is frozen because OOM killer wouldn't be able to free
* any memory and livelock. freezing_slow_path will tell the freezer
* that TIF_MEMDIE tasks should be ignored.
*/
__thaw_task(tsk);
atomic_inc(&oom_victims);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 37 | 77.08% | 2 | 50.00% |
| tetsuo handa | tetsuo handa | 10 | 20.83% | 1 | 25.00% |
| johannes weiner | johannes weiner | 1 | 2.08% | 1 | 25.00% |
| Total | 48 | 100.00% | 4 | 100.00% |
/**
* exit_oom_victim - note the exit of an OOM victim
*/
void exit_oom_victim(struct task_struct *tsk)
{
if (!test_and_clear_tsk_thread_flag(tsk, TIF_MEMDIE))
return;
atomic_dec(&tsk->signal->oom_victims);
if (!atomic_dec_return(&oom_victims))
wake_up_all(&oom_victims_wait);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 35 | 76.09% | 3 | 60.00% |
| tetsuo handa | tetsuo handa | 10 | 21.74% | 1 | 20.00% |
| johannes weiner | johannes weiner | 1 | 2.17% | 1 | 20.00% |
| Total | 46 | 100.00% | 5 | 100.00% |
/**
* oom_killer_disable - disable OOM killer
*
* Forces all page allocations to fail rather than trigger OOM killer.
* Will block and wait until all OOM victims are killed.
*
* The function cannot be called when there are runnable user tasks because
* the userspace would see unexpected allocation failures as a result. Any
* new usage of this function should be consulted with MM people.
*
* Returns true if successful and false if the OOM killer cannot be
* disabled.
*/
bool oom_killer_disable(void)
{
/*
* Make sure to not race with an ongoing OOM killer. Check that the
* current is not killed (possibly due to sharing the victim's memory).
*/
if (mutex_lock_killable(&oom_lock))
return false;
oom_killer_disabled = true;
mutex_unlock(&oom_lock);
wait_event(oom_victims_wait, !atomic_read(&oom_victims));
return true;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 38 | 86.36% | 3 | 60.00% |
| johannes weiner | johannes weiner | 3 | 6.82% | 1 | 20.00% |
| tetsuo handa | tetsuo handa | 3 | 6.82% | 1 | 20.00% |
| Total | 44 | 100.00% | 5 | 100.00% |
/**
* oom_killer_enable - enable OOM killer
*/
void oom_killer_enable(void)
{
oom_killer_disabled = false;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| michal hocko | michal hocko | 11 | 100.00% | 2 | 100.00% |
| Total | 11 | 100.00% | 2 | 100.00% |
/*
* Must be called while holding a reference to p, which will be released upon
* returning.
*/
void oom_kill_process(struct oom_control *oc, struct task_struct *p,
unsigned int points, unsigned long totalpages,
struct mem_cgroup *memcg, const char *message)
{
struct task_struct *victim = p;
struct task_struct *child;
struct task_struct *t;
struct mm_struct *mm;
unsigned int victim_points = 0;
static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
bool can_oom_reap = true;
/*
* If the task is already exiting, don't alarm the sysadmin or kill
* its children or threads, just set TIF_MEMDIE so it can die quickly
*/
task_lock(p);
if (p->mm && task_will_free_mem(p)) {
mark_oom_victim(p);
try_oom_reaper(p);
task_unlock(p);
put_task_struct(p);
return;
}
task_unlock(p);
if (__ratelimit(&oom_rs))
dump_header(oc, p, memcg);
pr_err("%s: Kill process %d (%s) score %u or sacrifice child\n",
message, task_pid_nr(p), p->comm, points);
/*
* If any of p's children has a different mm and is eligible for kill,
* the one with the highest oom_badness() score is sacrificed for its
* parent. This attempts to lose the minimal amount of work done while
* still freeing memory.
*/
read_lock(&tasklist_lock);
for_each_thread(p, t) {
list_for_each_entry(child, &t->children, sibling) {
unsigned int child_points;
if (process_shares_mm(child, p->mm))
continue;
/*
* oom_badness() returns 0 if the thread is unkillable
*/
child_points = oom_badness(child, memcg, oc->nodemask,
totalpages);
if (child_points > victim_points) {
put_task_struct(victim);
victim = child;
victim_points = child_points;
get_task_struct(victim);
}
}
}
read_unlock(&tasklist_lock);
p = find_lock_task_mm(victim);
if (!p) {
put_task_struct(victim);
return;
} else if (victim != p) {
get_task_struct(p);
put_task_struct(victim);
victim = p;
}
/* Get a reference to safely compare mm after task_unlock(victim) */
mm = victim->mm;
atomic_inc(&mm->mm_count);
/*
* We should send SIGKILL before setting TIF_MEMDIE in order to prevent
* the OOM victim from depleting the memory reserves from the user
* space under its control.
*/
do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true);
mark_oom_victim(victim);
pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n",
task_pid_nr(victim), victim->comm, K(victim->mm->total_vm),
K(get_mm_counter(victim->mm, MM_ANONPAGES)),
K(get_mm_counter(victim->mm, MM_FILEPAGES)),
K(get_mm_counter(victim->mm, MM_SHMEMPAGES)));
task_unlock(victim);
/*
* Kill all user processes sharing victim->mm in other thread groups, if
* any. They don't get access to memory reserves, though, to avoid
* depletion of all memory. This prevents mm->mmap_sem livelock when an
* oom killed thread cannot exit because it requires the semaphore and
* its contended by another thread trying to allocate memory itself.
* That thread will now get access to memory reserves since it has a
* pending fatal signal.
*/
rcu_read_lock();
for_each_process(p) {
if (!process_shares_mm(p, mm))
continue;
if (same_thread_group(p, victim))
continue;
if (unlikely(p->flags & PF_KTHREAD) || is_global_init(p) ||
p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
/*
* We cannot use oom_reaper for the mm shared by this
* process because it wouldn't get killed and so the
* memory might be still used.
*/
can_oom_reap = false;
continue;
}
do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
}
rcu_read_unlock();
if (can_oom_reap)
wake_oom_reaper(victim);
mmdrop(mm);
put_task_struct(victim);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 268 | 55.83% | 11 | 26.19% |
| michal hocko | michal hocko | 49 | 10.21% | 4 | 9.52% |
| oleg nesterov | oleg nesterov | 47 | 9.79% | 7 | 16.67% |
| tetsuo handa | tetsuo handa | 28 | 5.83% | 3 | 7.14% |
| andrea arcangeli | andrea arcangeli | 19 | 3.96% | 1 | 2.38% |
| jerome marchand | jerome marchand | 13 | 2.71% | 1 | 2.38% |
| kurt garloff | kurt garloff | 13 | 2.71% | 1 | 2.38% |
| nick piggin | nick piggin | 12 | 2.50% | 2 | 4.76% |
| linus torvalds | linus torvalds | 6 | 1.25% | 2 | 4.76% |
| christoph lameter | christoph lameter | 5 | 1.04% | 1 | 2.38% |
| kosaki motohiro | kosaki motohiro | 4 | 0.83% | 2 | 4.76% |
| johannes weiner | johannes weiner | 4 | 0.83% | 2 | 4.76% |
| chen jie | chen jie | 4 | 0.83% | 1 | 2.38% |
| matthias kaehlcke | matthias kaehlcke | 3 | 0.62% | 1 | 2.38% |
| pavel emelianov | pavel emelianov | 3 | 0.62% | 1 | 2.38% |
| wang long | wang long | 1 | 0.21% | 1 | 2.38% |
| andrew morton | andrew morton | 1 | 0.21% | 1 | 2.38% |
| Total | 480 | 100.00% | 42 | 100.00% |
#undef K
/*
* Determines whether the kernel must panic because of the panic_on_oom sysctl.
*/
void check_panic_on_oom(struct oom_control *oc, enum oom_constraint constraint,
struct mem_cgroup *memcg)
{
if (likely(!sysctl_panic_on_oom))
return;
if (sysctl_panic_on_oom != 2) {
/*
* panic_on_oom == 1 only affects CONSTRAINT_NONE, the kernel
* does not panic for cpuset, mempolicy, or memcg allocation
* failures.
*/
if (constraint != CONSTRAINT_NONE)
return;
}
/* Do not panic for oom kills triggered by sysrq */
if (is_sysrq_oom(oc))
return;
dump_header(oc, NULL, memcg);
panic("Out of memory: %s panic_on_oom is enabled\n",
sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide");
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 60 | 80.00% | 3 | 50.00% |
| oleg nesterov | oleg nesterov | 7 | 9.33% | 1 | 16.67% |
| balasubramani vivekanandan | balasubramani vivekanandan | 5 | 6.67% | 1 | 16.67% |
| yaowei bai | yaowei bai | 3 | 4.00% | 1 | 16.67% |
| Total | 75 | 100.00% | 6 | 100.00% |
static BLOCKING_NOTIFIER_HEAD(oom_notify_list);
int register_oom_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&oom_notify_list, nb);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| martin schwidefsky | martin schwidefsky | 19 | 100.00% | 1 | 100.00% |
| Total | 19 | 100.00% | 1 | 100.00% |
EXPORT_SYMBOL_GPL(register_oom_notifier);
int unregister_oom_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&oom_notify_list, nb);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| martin schwidefsky | martin schwidefsky | 19 | 100.00% | 1 | 100.00% |
| Total | 19 | 100.00% | 1 | 100.00% |
EXPORT_SYMBOL_GPL(unregister_oom_notifier);
/**
* out_of_memory - kill the "best" process when we run out of memory
* @oc: pointer to struct oom_control
*
* If we run out of memory, we have the choice between either
* killing a random task (bad), letting the system crash (worse)
* OR try to be smart about which process to kill. Note that we
* don't have to be perfect here, we just have to be good.
*/
bool out_of_memory(struct oom_control *oc)
{
struct task_struct *p;
unsigned long totalpages;
unsigned long freed = 0;
unsigned int uninitialized_var(points);
enum oom_constraint constraint = CONSTRAINT_NONE;
if (oom_killer_disabled)
return false;
blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
if (freed > 0)
/* Got some memory back in the last second. */
return true;
/*
* If current has a pending SIGKILL or is exiting, then automatically
* select it. The goal is to allow it to allocate so that it may
* quickly exit and free its memory.
*
* But don't select if current has already released its mm and cleared
* TIF_MEMDIE flag at exit_mm(), otherwise an OOM livelock may occur.
*/
if (current->mm &&
(fatal_signal_pending(current) || task_will_free_mem(current))) {
mark_oom_victim(current);
try_oom_reaper(current);
return true;
}
/*
* The OOM killer does not compensate for IO-less reclaim.
* pagefault_out_of_memory lost its gfp context so we have to
* make sure exclude 0 mask - all other users should have at least
* ___GFP_DIRECT_RECLAIM to get here.
*/
if (oc->gfp_mask && !(oc->gfp_mask & (__GFP_FS|__GFP_NOFAIL)))
return true;
/*
* Check if there were limitations on the allocation (only relevant for
* NUMA) that may require different handling.
*/
constraint = constrained_alloc(oc, &totalpages);
if (constraint != CONSTRAINT_MEMORY_POLICY)
oc->nodemask = NULL;
check_panic_on_oom(oc, constraint, NULL);
if (sysctl_oom_kill_allocating_task && current->mm &&
!oom_unkillable_task(current, NULL, oc->nodemask) &&
current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) {
get_task_struct(current);
oom_kill_process(oc, current, 0, totalpages, NULL,
"Out of memory (oom_kill_allocating_task)");
return true;
}
p = select_bad_process(oc, &points, totalpages);
/* Found nothing?!?! Either we hang forever, or we panic. */
if (!p && !is_sysrq_oom(oc)) {
dump_header(oc, NULL, NULL);
panic("Out of memory and no killable processes...\n");
}
if (p && p != (void *)-1UL) {
oom_kill_process(oc, p, points, totalpages, NULL,
"Out of memory");
/*
* Give the killed process a good chance to exit before trying
* to allocate memory again.
*/
schedule_timeout_killable(1);
}
return true;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 156 | 54.36% | 15 | 46.88% |
| nick piggin | nick piggin | 48 | 16.72% | 1 | 3.12% |
| michal hocko | michal hocko | 32 | 11.15% | 4 | 12.50% |
| kosaki motohiro | kosaki motohiro | 13 | 4.53% | 2 | 6.25% |
| johannes weiner | johannes weiner | 11 | 3.83% | 2 | 6.25% |
| tetsuo handa | tetsuo handa | 7 | 2.44% | 1 | 3.12% |
| yaowei bai | yaowei bai | 4 | 1.39% | 1 | 3.12% |
| rusty russell | rusty russell | 4 | 1.39% | 1 | 3.12% |
| linus torvalds | linus torvalds | 3 | 1.05% | 1 | 3.12% |
| andrew morton | andrew morton | 3 | 1.05% | 1 | 3.12% |
| oleg nesterov | oleg nesterov | 3 | 1.05% | 1 | 3.12% |
| balasubramani vivekanandan | balasubramani vivekanandan | 2 | 0.70% | 1 | 3.12% |
| andrea arcangeli | andrea arcangeli | 1 | 0.35% | 1 | 3.12% |
| Total | 287 | 100.00% | 32 | 100.00% |
/*
* The pagefault handler calls here because it is out of memory, so kill a
* memory-hogging task. If any populated zone has ZONE_OOM_LOCKED set, a
* parallel oom killing is already in progress so do nothing.
*/
void pagefault_out_of_memory(void)
{
struct oom_control oc = {
.zonelist = NULL,
.nodemask = NULL,
.gfp_mask = 0,
.order = 0,
};
if (mem_cgroup_oom_synchronize(true))
return;
if (!mutex_trylock(&oom_lock))
return;
if (!out_of_memory(&oc)) {
/*
* There shouldn't be any user tasks runnable while the
* OOM killer is disabled, so the current task has to
* be a racing OOM victim for which oom_killer_disable()
* is waiting for.
*/
WARN_ON(test_thread_flag(TIF_MEMDIE));
}
mutex_unlock(&oom_lock);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 43 | 55.84% | 3 | 42.86% |
| johannes weiner | johannes weiner | 19 | 24.68% | 3 | 42.86% |
| michal hocko | michal hocko | 15 | 19.48% | 1 | 14.29% |
| Total | 77 | 100.00% | 7 | 100.00% |
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david rientjes | david rientjes | 1122 | 35.65% | 49 | 32.03% |
| michal hocko | michal hocko | 1031 | 32.76% | 19 | 12.42% |
| kosaki motohiro | kosaki motohiro | 170 | 5.40% | 10 | 6.54% |
| oleg nesterov | oleg nesterov | 159 | 5.05% | 9 | 5.88% |
| tetsuo handa | tetsuo handa | 73 | 2.32% | 7 | 4.58% |
| pre-git | pre-git | 67 | 2.13% | 1 | 0.65% |
| nick piggin | nick piggin | 62 | 1.97% | 3 | 1.96% |
| martin schwidefsky | martin schwidefsky | 59 | 1.87% | 1 | 0.65% |
| kamezawa hiroyuki | kamezawa hiroyuki | 59 | 1.87% | 3 | 1.96% |
| johannes weiner | johannes weiner | 53 | 1.68% | 5 | 3.27% |
| christoph lameter | christoph lameter | 37 | 1.18% | 2 | 1.31% |
| yaowei bai | yaowei bai | 32 | 1.02% | 1 | 0.65% |
| kirill a. shutemov | kirill a. shutemov | 27 | 0.86% | 2 | 1.31% |
| andrea arcangeli | andrea arcangeli | 23 | 0.73% | 1 | 0.65% |
| mel gorman | mel gorman | 22 | 0.70% | 2 | 1.31% |
| vladimir davydov | vladimir davydov | 16 | 0.51% | 2 | 1.31% |
| kurt garloff | kurt garloff | 15 | 0.48% | 1 | 0.65% |
| jerome marchand | jerome marchand | 13 | 0.41% | 1 | 0.65% |
| rusty russell | rusty russell | 11 | 0.35% | 1 | 0.65% |
| andrew morton | andrew morton | 10 | 0.32% | 4 | 2.61% |
| linus torvalds | linus torvalds | 9 | 0.29% | 3 | 1.96% |
| balasubramani vivekanandan | balasubramani vivekanandan | 7 | 0.22% | 1 | 0.65% |
| tim schmielau | tim schmielau | 7 | 0.22% | 2 | 1.31% |
| eric w. biederman | eric w. biederman | 6 | 0.19% | 1 | 0.65% |
| vlastimil babka | vlastimil babka | 6 | 0.19% | 1 | 0.65% |
| pavel emelianov | pavel emelianov | 6 | 0.19% | 2 | 1.31% |
| daisuke nishimura | daisuke nishimura | 6 | 0.19% | 1 | 0.65% |
| alexey dobriyan | alexey dobriyan | 6 | 0.19% | 2 | 1.31% |
| sha zhengju | sha zhengju | 5 | 0.16% | 1 | 0.65% |
| david howells | david howells | 5 | 0.16% | 2 | 1.31% |
| chen jie | chen jie | 4 | 0.13% | 1 | 0.65% |
| tejun heo | tejun heo | 3 | 0.10% | 1 | 0.65% |
| paul jackson | paul jackson | 3 | 0.10% | 1 | 0.65% |
| matthias kaehlcke | matthias kaehlcke | 3 | 0.10% | 1 | 0.65% |
| ingo molnar | ingo molnar | 2 | 0.06% | 1 | 0.65% |
| andrew g. morgan | andrew g. morgan | 1 | 0.03% | 1 | 0.65% |
| frantisek hrbata | frantisek hrbata | 1 | 0.03% | 1 | 0.65% |
| cyrill gorcunov | cyrill gorcunov | 1 | 0.03% | 1 | 0.65% |
| paul gortmaker | paul gortmaker | 1 | 0.03% | 1 | 0.65% |
| lai jiangshan | lai jiangshan | 1 | 0.03% | 1 | 0.65% |
| eric paris | eric paris | 1 | 0.03% | 1 | 0.65% |
| wang long | wang long | 1 | 0.03% | 1 | 0.65% |
| joe perches | joe perches | 1 | 0.03% | 1 | 0.65% |
| Total | 3147 | 100.00% | 153 | 100.00% |
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