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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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1e11ad8dc4
If the privileges given to root threads (3% of allowable memory) or a
negative value of /proc/pid/oom_score_adj happen to exceed the amount of
rss of a thread, its badness score overflows as a result of commit
a7f638f999
("mm, oom: normalize oom scores to oom_score_adj scale only
for userspace").
Fix this by making the type signed and return 1, meaning the thread is
still eligible for kill, if the value is negative.
Reported-by: Dave Jones <davej@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
771 lines
22 KiB
C
771 lines
22 KiB
C
/*
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* linux/mm/oom_kill.c
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*
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* Copyright (C) 1998,2000 Rik van Riel
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* Thanks go out to Claus Fischer for some serious inspiration and
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* for goading me into coding this file...
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* Copyright (C) 2010 Google, Inc.
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* Rewritten by David Rientjes
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*
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* The routines in this file are used to kill a process when
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* we're seriously out of memory. This gets called from __alloc_pages()
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* in mm/page_alloc.c when we really run out of memory.
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*
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* Since we won't call these routines often (on a well-configured
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* machine) this file will double as a 'coding guide' and a signpost
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* for newbie kernel hackers. It features several pointers to major
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* kernel subsystems and hints as to where to find out what things do.
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*/
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#include <linux/oom.h>
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#include <linux/mm.h>
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#include <linux/err.h>
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#include <linux/gfp.h>
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#include <linux/sched.h>
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#include <linux/swap.h>
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#include <linux/timex.h>
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#include <linux/jiffies.h>
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#include <linux/cpuset.h>
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#include <linux/export.h>
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#include <linux/notifier.h>
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#include <linux/memcontrol.h>
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#include <linux/mempolicy.h>
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#include <linux/security.h>
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#include <linux/ptrace.h>
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#include <linux/freezer.h>
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#include <linux/ftrace.h>
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#include <linux/ratelimit.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/oom.h>
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int sysctl_panic_on_oom;
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int sysctl_oom_kill_allocating_task;
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int sysctl_oom_dump_tasks = 1;
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static DEFINE_SPINLOCK(zone_scan_lock);
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/*
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* compare_swap_oom_score_adj() - compare and swap current's oom_score_adj
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* @old_val: old oom_score_adj for compare
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* @new_val: new oom_score_adj for swap
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*
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* Sets the oom_score_adj value for current to @new_val iff its present value is
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* @old_val. Usually used to reinstate a previous value to prevent racing with
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* userspacing tuning the value in the interim.
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*/
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void compare_swap_oom_score_adj(int old_val, int new_val)
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{
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struct sighand_struct *sighand = current->sighand;
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spin_lock_irq(&sighand->siglock);
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if (current->signal->oom_score_adj == old_val)
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current->signal->oom_score_adj = new_val;
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trace_oom_score_adj_update(current);
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spin_unlock_irq(&sighand->siglock);
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}
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/**
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* test_set_oom_score_adj() - set current's oom_score_adj and return old value
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* @new_val: new oom_score_adj value
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*
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* Sets the oom_score_adj value for current to @new_val with proper
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* synchronization and returns the old value. Usually used to temporarily
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* set a value, save the old value in the caller, and then reinstate it later.
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*/
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int test_set_oom_score_adj(int new_val)
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{
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struct sighand_struct *sighand = current->sighand;
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int old_val;
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spin_lock_irq(&sighand->siglock);
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old_val = current->signal->oom_score_adj;
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current->signal->oom_score_adj = new_val;
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trace_oom_score_adj_update(current);
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spin_unlock_irq(&sighand->siglock);
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return old_val;
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}
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#ifdef CONFIG_NUMA
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/**
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* has_intersects_mems_allowed() - check task eligiblity for kill
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* @tsk: task struct of which task to consider
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* @mask: nodemask passed to page allocator for mempolicy ooms
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*
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* Task eligibility is determined by whether or not a candidate task, @tsk,
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* shares the same mempolicy nodes as current if it is bound by such a policy
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* and whether or not it has the same set of allowed cpuset nodes.
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*/
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static bool has_intersects_mems_allowed(struct task_struct *tsk,
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const nodemask_t *mask)
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{
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struct task_struct *start = tsk;
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do {
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if (mask) {
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/*
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* If this is a mempolicy constrained oom, tsk's
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* cpuset is irrelevant. Only return true if its
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* mempolicy intersects current, otherwise it may be
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* needlessly killed.
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*/
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if (mempolicy_nodemask_intersects(tsk, mask))
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return true;
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} else {
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/*
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* This is not a mempolicy constrained oom, so only
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* check the mems of tsk's cpuset.
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*/
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if (cpuset_mems_allowed_intersects(current, tsk))
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return true;
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}
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} while_each_thread(start, tsk);
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return false;
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}
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#else
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static bool has_intersects_mems_allowed(struct task_struct *tsk,
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const nodemask_t *mask)
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{
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return true;
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}
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#endif /* CONFIG_NUMA */
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/*
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* The process p may have detached its own ->mm while exiting or through
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* use_mm(), but one or more of its subthreads may still have a valid
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* pointer. Return p, or any of its subthreads with a valid ->mm, with
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* task_lock() held.
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*/
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struct task_struct *find_lock_task_mm(struct task_struct *p)
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{
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struct task_struct *t = p;
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do {
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task_lock(t);
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if (likely(t->mm))
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return t;
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task_unlock(t);
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} while_each_thread(p, t);
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return NULL;
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}
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/* return true if the task is not adequate as candidate victim task. */
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static bool oom_unkillable_task(struct task_struct *p,
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const struct mem_cgroup *memcg, const nodemask_t *nodemask)
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{
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if (is_global_init(p))
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return true;
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if (p->flags & PF_KTHREAD)
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return true;
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/* When mem_cgroup_out_of_memory() and p is not member of the group */
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if (memcg && !task_in_mem_cgroup(p, memcg))
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return true;
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/* p may not have freeable memory in nodemask */
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if (!has_intersects_mems_allowed(p, nodemask))
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return true;
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return false;
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}
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/**
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* oom_badness - heuristic function to determine which candidate task to kill
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* @p: task struct of which task we should calculate
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* @totalpages: total present RAM allowed for page allocation
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*
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* The heuristic for determining which task to kill is made to be as simple and
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* predictable as possible. The goal is to return the highest value for the
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* task consuming the most memory to avoid subsequent oom failures.
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*/
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unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
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const nodemask_t *nodemask, unsigned long totalpages)
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{
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long points;
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if (oom_unkillable_task(p, memcg, nodemask))
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return 0;
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p = find_lock_task_mm(p);
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if (!p)
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return 0;
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if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
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task_unlock(p);
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return 0;
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}
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/*
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* The baseline for the badness score is the proportion of RAM that each
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* task's rss, pagetable and swap space use.
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*/
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points = get_mm_rss(p->mm) + p->mm->nr_ptes +
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get_mm_counter(p->mm, MM_SWAPENTS);
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task_unlock(p);
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/*
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* Root processes get 3% bonus, just like the __vm_enough_memory()
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* implementation used by LSMs.
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*/
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if (has_capability_noaudit(p, CAP_SYS_ADMIN))
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points -= 30 * totalpages / 1000;
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/*
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* /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may
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* either completely disable oom killing or always prefer a certain
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* task.
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*/
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points += p->signal->oom_score_adj * totalpages / 1000;
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/*
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* Never return 0 for an eligible task regardless of the root bonus and
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* oom_score_adj (oom_score_adj can't be OOM_SCORE_ADJ_MIN here).
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*/
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return points > 0 ? points : 1;
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}
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/*
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* Determine the type of allocation constraint.
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*/
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#ifdef CONFIG_NUMA
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static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
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gfp_t gfp_mask, nodemask_t *nodemask,
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unsigned long *totalpages)
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{
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struct zone *zone;
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struct zoneref *z;
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enum zone_type high_zoneidx = gfp_zone(gfp_mask);
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bool cpuset_limited = false;
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int nid;
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/* Default to all available memory */
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*totalpages = totalram_pages + total_swap_pages;
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if (!zonelist)
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return CONSTRAINT_NONE;
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/*
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* Reach here only when __GFP_NOFAIL is used. So, we should avoid
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* to kill current.We have to random task kill in this case.
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* Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now.
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*/
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if (gfp_mask & __GFP_THISNODE)
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return CONSTRAINT_NONE;
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/*
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* This is not a __GFP_THISNODE allocation, so a truncated nodemask in
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* the page allocator means a mempolicy is in effect. Cpuset policy
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* is enforced in get_page_from_freelist().
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*/
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if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask)) {
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*totalpages = total_swap_pages;
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for_each_node_mask(nid, *nodemask)
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*totalpages += node_spanned_pages(nid);
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return CONSTRAINT_MEMORY_POLICY;
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}
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/* Check this allocation failure is caused by cpuset's wall function */
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for_each_zone_zonelist_nodemask(zone, z, zonelist,
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high_zoneidx, nodemask)
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if (!cpuset_zone_allowed_softwall(zone, gfp_mask))
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cpuset_limited = true;
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if (cpuset_limited) {
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*totalpages = total_swap_pages;
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for_each_node_mask(nid, cpuset_current_mems_allowed)
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*totalpages += node_spanned_pages(nid);
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return CONSTRAINT_CPUSET;
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}
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return CONSTRAINT_NONE;
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}
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#else
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static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
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gfp_t gfp_mask, nodemask_t *nodemask,
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unsigned long *totalpages)
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{
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*totalpages = totalram_pages + total_swap_pages;
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return CONSTRAINT_NONE;
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}
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#endif
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/*
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* Simple selection loop. We chose the process with the highest
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* number of 'points'. We expect the caller will lock the tasklist.
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*
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* (not docbooked, we don't want this one cluttering up the manual)
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*/
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static struct task_struct *select_bad_process(unsigned int *ppoints,
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unsigned long totalpages, struct mem_cgroup *memcg,
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const nodemask_t *nodemask, bool force_kill)
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{
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struct task_struct *g, *p;
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struct task_struct *chosen = NULL;
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unsigned long chosen_points = 0;
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do_each_thread(g, p) {
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unsigned int points;
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if (p->exit_state)
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continue;
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if (oom_unkillable_task(p, memcg, nodemask))
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continue;
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/*
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* This task already has access to memory reserves and is
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* being killed. Don't allow any other task access to the
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* memory reserve.
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*
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* Note: this may have a chance of deadlock if it gets
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* blocked waiting for another task which itself is waiting
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* for memory. Is there a better alternative?
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*/
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if (test_tsk_thread_flag(p, TIF_MEMDIE)) {
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if (unlikely(frozen(p)))
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__thaw_task(p);
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if (!force_kill)
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return ERR_PTR(-1UL);
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}
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if (!p->mm)
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continue;
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if (p->flags & PF_EXITING) {
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/*
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* If p is the current task and is in the process of
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* releasing memory, we allow the "kill" to set
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* TIF_MEMDIE, which will allow it to gain access to
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* memory reserves. Otherwise, it may stall forever.
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*
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* The loop isn't broken here, however, in case other
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* threads are found to have already been oom killed.
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*/
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if (p == current) {
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chosen = p;
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chosen_points = ULONG_MAX;
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} else if (!force_kill) {
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/*
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* If this task is not being ptraced on exit,
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* then wait for it to finish before killing
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* some other task unnecessarily.
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*/
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if (!(p->group_leader->ptrace & PT_TRACE_EXIT))
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return ERR_PTR(-1UL);
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}
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}
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points = oom_badness(p, memcg, nodemask, totalpages);
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if (points > chosen_points) {
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chosen = p;
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chosen_points = points;
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}
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} while_each_thread(g, p);
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*ppoints = chosen_points * 1000 / totalpages;
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return chosen;
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}
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/**
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* dump_tasks - dump current memory state of all system tasks
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* @mem: current's memory controller, if constrained
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* @nodemask: nodemask passed to page allocator for mempolicy ooms
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*
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* Dumps the current memory state of all eligible tasks. Tasks not in the same
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* memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes
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* are not shown.
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* State information includes task's pid, uid, tgid, vm size, rss, cpu, oom_adj
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* value, oom_score_adj value, and name.
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*
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* Call with tasklist_lock read-locked.
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*/
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static void dump_tasks(const struct mem_cgroup *memcg, const nodemask_t *nodemask)
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{
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struct task_struct *p;
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struct task_struct *task;
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pr_info("[ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name\n");
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for_each_process(p) {
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if (oom_unkillable_task(p, memcg, nodemask))
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continue;
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task = find_lock_task_mm(p);
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if (!task) {
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/*
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* This is a kthread or all of p's threads have already
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* detached their mm's. There's no need to report
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* them; they can't be oom killed anyway.
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*/
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continue;
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}
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pr_info("[%5d] %5d %5d %8lu %8lu %3u %3d %5d %s\n",
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task->pid, from_kuid(&init_user_ns, task_uid(task)),
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task->tgid, task->mm->total_vm, get_mm_rss(task->mm),
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task_cpu(task), task->signal->oom_adj,
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task->signal->oom_score_adj, task->comm);
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task_unlock(task);
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}
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}
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static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
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struct mem_cgroup *memcg, const nodemask_t *nodemask)
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{
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task_lock(current);
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pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, "
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"oom_adj=%d, oom_score_adj=%d\n",
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current->comm, gfp_mask, order, current->signal->oom_adj,
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current->signal->oom_score_adj);
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cpuset_print_task_mems_allowed(current);
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task_unlock(current);
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dump_stack();
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mem_cgroup_print_oom_info(memcg, p);
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show_mem(SHOW_MEM_FILTER_NODES);
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if (sysctl_oom_dump_tasks)
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dump_tasks(memcg, nodemask);
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}
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#define K(x) ((x) << (PAGE_SHIFT-10))
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static void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
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unsigned int points, unsigned long totalpages,
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struct mem_cgroup *memcg, nodemask_t *nodemask,
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const char *message)
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{
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struct task_struct *victim = p;
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struct task_struct *child;
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struct task_struct *t = p;
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struct mm_struct *mm;
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unsigned int victim_points = 0;
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static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
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DEFAULT_RATELIMIT_BURST);
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/*
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* If the task is already exiting, don't alarm the sysadmin or kill
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* its children or threads, just set TIF_MEMDIE so it can die quickly
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*/
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if (p->flags & PF_EXITING) {
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set_tsk_thread_flag(p, TIF_MEMDIE);
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return;
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}
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if (__ratelimit(&oom_rs))
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dump_header(p, gfp_mask, order, memcg, nodemask);
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task_lock(p);
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pr_err("%s: Kill process %d (%s) score %d or sacrifice child\n",
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message, task_pid_nr(p), p->comm, points);
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task_unlock(p);
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/*
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* If any of p's children has a different mm and is eligible for kill,
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* the one with the highest oom_badness() score is sacrificed for its
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* parent. This attempts to lose the minimal amount of work done while
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* still freeing memory.
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*/
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do {
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list_for_each_entry(child, &t->children, sibling) {
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unsigned int child_points;
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if (child->mm == p->mm)
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continue;
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/*
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* oom_badness() returns 0 if the thread is unkillable
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*/
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child_points = oom_badness(child, memcg, nodemask,
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totalpages);
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if (child_points > victim_points) {
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victim = child;
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victim_points = child_points;
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}
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}
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} while_each_thread(p, t);
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victim = find_lock_task_mm(victim);
|
|
if (!victim)
|
|
return;
|
|
|
|
/* mm cannot safely be dereferenced after task_unlock(victim) */
|
|
mm = victim->mm;
|
|
pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-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)));
|
|
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.
|
|
*/
|
|
for_each_process(p)
|
|
if (p->mm == mm && !same_thread_group(p, victim) &&
|
|
!(p->flags & PF_KTHREAD)) {
|
|
if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
|
|
continue;
|
|
|
|
task_lock(p); /* Protect ->comm from prctl() */
|
|
pr_err("Kill process %d (%s) sharing same memory\n",
|
|
task_pid_nr(p), p->comm);
|
|
task_unlock(p);
|
|
do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
|
|
}
|
|
|
|
set_tsk_thread_flag(victim, TIF_MEMDIE);
|
|
do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true);
|
|
}
|
|
#undef K
|
|
|
|
/*
|
|
* Determines whether the kernel must panic because of the panic_on_oom sysctl.
|
|
*/
|
|
static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
|
|
int order, const nodemask_t *nodemask)
|
|
{
|
|
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;
|
|
}
|
|
read_lock(&tasklist_lock);
|
|
dump_header(NULL, gfp_mask, order, NULL, nodemask);
|
|
read_unlock(&tasklist_lock);
|
|
panic("Out of memory: %s panic_on_oom is enabled\n",
|
|
sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide");
|
|
}
|
|
|
|
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
|
|
void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
|
|
int order)
|
|
{
|
|
unsigned long limit;
|
|
unsigned int points = 0;
|
|
struct task_struct *p;
|
|
|
|
/*
|
|
* If current has a pending SIGKILL, then automatically select it. The
|
|
* goal is to allow it to allocate so that it may quickly exit and free
|
|
* its memory.
|
|
*/
|
|
if (fatal_signal_pending(current)) {
|
|
set_thread_flag(TIF_MEMDIE);
|
|
return;
|
|
}
|
|
|
|
check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
|
|
limit = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1;
|
|
read_lock(&tasklist_lock);
|
|
p = select_bad_process(&points, limit, memcg, NULL, false);
|
|
if (p && PTR_ERR(p) != -1UL)
|
|
oom_kill_process(p, gfp_mask, order, points, limit, memcg, NULL,
|
|
"Memory cgroup out of memory");
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
#endif
|
|
|
|
static BLOCKING_NOTIFIER_HEAD(oom_notify_list);
|
|
|
|
int register_oom_notifier(struct notifier_block *nb)
|
|
{
|
|
return blocking_notifier_chain_register(&oom_notify_list, nb);
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_oom_notifier);
|
|
|
|
int unregister_oom_notifier(struct notifier_block *nb)
|
|
{
|
|
return blocking_notifier_chain_unregister(&oom_notify_list, nb);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_oom_notifier);
|
|
|
|
/*
|
|
* Try to acquire the OOM killer lock for the zones in zonelist. Returns zero
|
|
* if a parallel OOM killing is already taking place that includes a zone in
|
|
* the zonelist. Otherwise, locks all zones in the zonelist and returns 1.
|
|
*/
|
|
int try_set_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask)
|
|
{
|
|
struct zoneref *z;
|
|
struct zone *zone;
|
|
int ret = 1;
|
|
|
|
spin_lock(&zone_scan_lock);
|
|
for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
|
|
if (zone_is_oom_locked(zone)) {
|
|
ret = 0;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
|
|
/*
|
|
* Lock each zone in the zonelist under zone_scan_lock so a
|
|
* parallel invocation of try_set_zonelist_oom() doesn't succeed
|
|
* when it shouldn't.
|
|
*/
|
|
zone_set_flag(zone, ZONE_OOM_LOCKED);
|
|
}
|
|
|
|
out:
|
|
spin_unlock(&zone_scan_lock);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Clears the ZONE_OOM_LOCKED flag for all zones in the zonelist so that failed
|
|
* allocation attempts with zonelists containing them may now recall the OOM
|
|
* killer, if necessary.
|
|
*/
|
|
void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask)
|
|
{
|
|
struct zoneref *z;
|
|
struct zone *zone;
|
|
|
|
spin_lock(&zone_scan_lock);
|
|
for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
|
|
zone_clear_flag(zone, ZONE_OOM_LOCKED);
|
|
}
|
|
spin_unlock(&zone_scan_lock);
|
|
}
|
|
|
|
/*
|
|
* Try to acquire the oom killer lock for all system zones. Returns zero if a
|
|
* parallel oom killing is taking place, otherwise locks all zones and returns
|
|
* non-zero.
|
|
*/
|
|
static int try_set_system_oom(void)
|
|
{
|
|
struct zone *zone;
|
|
int ret = 1;
|
|
|
|
spin_lock(&zone_scan_lock);
|
|
for_each_populated_zone(zone)
|
|
if (zone_is_oom_locked(zone)) {
|
|
ret = 0;
|
|
goto out;
|
|
}
|
|
for_each_populated_zone(zone)
|
|
zone_set_flag(zone, ZONE_OOM_LOCKED);
|
|
out:
|
|
spin_unlock(&zone_scan_lock);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Clears ZONE_OOM_LOCKED for all system zones so that failed allocation
|
|
* attempts or page faults may now recall the oom killer, if necessary.
|
|
*/
|
|
static void clear_system_oom(void)
|
|
{
|
|
struct zone *zone;
|
|
|
|
spin_lock(&zone_scan_lock);
|
|
for_each_populated_zone(zone)
|
|
zone_clear_flag(zone, ZONE_OOM_LOCKED);
|
|
spin_unlock(&zone_scan_lock);
|
|
}
|
|
|
|
/**
|
|
* out_of_memory - kill the "best" process when we run out of memory
|
|
* @zonelist: zonelist pointer
|
|
* @gfp_mask: memory allocation flags
|
|
* @order: amount of memory being requested as a power of 2
|
|
* @nodemask: nodemask passed to page allocator
|
|
* @force_kill: true if a task must be killed, even if others are exiting
|
|
*
|
|
* 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.
|
|
*/
|
|
void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
|
|
int order, nodemask_t *nodemask, bool force_kill)
|
|
{
|
|
const nodemask_t *mpol_mask;
|
|
struct task_struct *p;
|
|
unsigned long totalpages;
|
|
unsigned long freed = 0;
|
|
unsigned int points;
|
|
enum oom_constraint constraint = CONSTRAINT_NONE;
|
|
int killed = 0;
|
|
|
|
blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
|
|
if (freed > 0)
|
|
/* Got some memory back in the last second. */
|
|
return;
|
|
|
|
/*
|
|
* If current has a pending SIGKILL, then automatically select it. The
|
|
* goal is to allow it to allocate so that it may quickly exit and free
|
|
* its memory.
|
|
*/
|
|
if (fatal_signal_pending(current)) {
|
|
set_thread_flag(TIF_MEMDIE);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Check if there were limitations on the allocation (only relevant for
|
|
* NUMA) that may require different handling.
|
|
*/
|
|
constraint = constrained_alloc(zonelist, gfp_mask, nodemask,
|
|
&totalpages);
|
|
mpol_mask = (constraint == CONSTRAINT_MEMORY_POLICY) ? nodemask : NULL;
|
|
check_panic_on_oom(constraint, gfp_mask, order, mpol_mask);
|
|
|
|
read_lock(&tasklist_lock);
|
|
if (sysctl_oom_kill_allocating_task &&
|
|
!oom_unkillable_task(current, NULL, nodemask) &&
|
|
current->mm) {
|
|
oom_kill_process(current, gfp_mask, order, 0, totalpages, NULL,
|
|
nodemask,
|
|
"Out of memory (oom_kill_allocating_task)");
|
|
goto out;
|
|
}
|
|
|
|
p = select_bad_process(&points, totalpages, NULL, mpol_mask,
|
|
force_kill);
|
|
/* Found nothing?!?! Either we hang forever, or we panic. */
|
|
if (!p) {
|
|
dump_header(NULL, gfp_mask, order, NULL, mpol_mask);
|
|
read_unlock(&tasklist_lock);
|
|
panic("Out of memory and no killable processes...\n");
|
|
}
|
|
if (PTR_ERR(p) != -1UL) {
|
|
oom_kill_process(p, gfp_mask, order, points, totalpages, NULL,
|
|
nodemask, "Out of memory");
|
|
killed = 1;
|
|
}
|
|
out:
|
|
read_unlock(&tasklist_lock);
|
|
|
|
/*
|
|
* Give "p" a good chance of killing itself before we
|
|
* retry to allocate memory unless "p" is current
|
|
*/
|
|
if (killed && !test_thread_flag(TIF_MEMDIE))
|
|
schedule_timeout_uninterruptible(1);
|
|
}
|
|
|
|
/*
|
|
* The pagefault handler calls here because it is out of memory, so kill a
|
|
* memory-hogging task. If a populated zone has ZONE_OOM_LOCKED set, a parallel
|
|
* oom killing is already in progress so do nothing. If a task is found with
|
|
* TIF_MEMDIE set, it has been killed so do nothing and allow it to exit.
|
|
*/
|
|
void pagefault_out_of_memory(void)
|
|
{
|
|
if (try_set_system_oom()) {
|
|
out_of_memory(NULL, 0, 0, NULL, false);
|
|
clear_system_oom();
|
|
}
|
|
if (!test_thread_flag(TIF_MEMDIE))
|
|
schedule_timeout_uninterruptible(1);
|
|
}
|