forked from luck/tmp_suning_uos_patched
36324a990c
When oom_reaper manages to unmap all the eligible vmas there shouldn't be much of the freable memory held by the oom victim left anymore so it makes sense to clear the TIF_MEMDIE flag for the victim and allow the OOM killer to select another task. The lack of TIF_MEMDIE also means that the victim cannot access memory reserves anymore but that shouldn't be a problem because it would get the access again if it needs to allocate and hits the OOM killer again due to the fatal_signal_pending resp. PF_EXITING check. We can safely hide the task from the OOM killer because it is clearly not a good candidate anymore as everyhing reclaimable has been torn down already. This patch will allow to cap the time an OOM victim can keep TIF_MEMDIE and thus hold off further global OOM killer actions granted the oom reaper is able to take mmap_sem for the associated mm struct. This is not guaranteed now but further steps should make sure that mmap_sem for write should be blocked killable which will help to reduce such a lock contention. This is not done by this patch. Note that exit_oom_victim might be called on a remote task from __oom_reap_task now so we have to check and clear the flag atomically otherwise we might race and underflow oom_victims or wake up waiters too early. Signed-off-by: Michal Hocko <mhocko@suse.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Andrea Argangeli <andrea@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
121 lines
3.2 KiB
C
121 lines
3.2 KiB
C
#ifndef __INCLUDE_LINUX_OOM_H
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#define __INCLUDE_LINUX_OOM_H
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#include <linux/sched.h>
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#include <linux/types.h>
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#include <linux/nodemask.h>
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#include <uapi/linux/oom.h>
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struct zonelist;
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struct notifier_block;
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struct mem_cgroup;
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struct task_struct;
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/*
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* Details of the page allocation that triggered the oom killer that are used to
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* determine what should be killed.
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*/
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struct oom_control {
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/* Used to determine cpuset */
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struct zonelist *zonelist;
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/* Used to determine mempolicy */
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nodemask_t *nodemask;
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/* Used to determine cpuset and node locality requirement */
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const gfp_t gfp_mask;
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/*
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* order == -1 means the oom kill is required by sysrq, otherwise only
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* for display purposes.
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*/
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const int order;
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};
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/*
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* Types of limitations to the nodes from which allocations may occur
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*/
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enum oom_constraint {
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CONSTRAINT_NONE,
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CONSTRAINT_CPUSET,
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CONSTRAINT_MEMORY_POLICY,
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CONSTRAINT_MEMCG,
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};
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enum oom_scan_t {
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OOM_SCAN_OK, /* scan thread and find its badness */
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OOM_SCAN_CONTINUE, /* do not consider thread for oom kill */
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OOM_SCAN_ABORT, /* abort the iteration and return */
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OOM_SCAN_SELECT, /* always select this thread first */
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};
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/* Thread is the potential origin of an oom condition; kill first on oom */
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#define OOM_FLAG_ORIGIN ((__force oom_flags_t)0x1)
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extern struct mutex oom_lock;
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static inline void set_current_oom_origin(void)
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{
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current->signal->oom_flags |= OOM_FLAG_ORIGIN;
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}
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static inline void clear_current_oom_origin(void)
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{
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current->signal->oom_flags &= ~OOM_FLAG_ORIGIN;
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}
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static inline bool oom_task_origin(const struct task_struct *p)
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{
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return !!(p->signal->oom_flags & OOM_FLAG_ORIGIN);
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}
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extern void mark_oom_victim(struct task_struct *tsk);
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extern unsigned long oom_badness(struct task_struct *p,
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struct mem_cgroup *memcg, const nodemask_t *nodemask,
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unsigned long totalpages);
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extern int oom_kills_count(void);
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extern void note_oom_kill(void);
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extern void oom_kill_process(struct oom_control *oc, struct task_struct *p,
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unsigned int points, unsigned long totalpages,
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struct mem_cgroup *memcg, const char *message);
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extern void check_panic_on_oom(struct oom_control *oc,
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enum oom_constraint constraint,
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struct mem_cgroup *memcg);
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extern enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
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struct task_struct *task, unsigned long totalpages);
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extern bool out_of_memory(struct oom_control *oc);
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extern void exit_oom_victim(struct task_struct *tsk);
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extern int register_oom_notifier(struct notifier_block *nb);
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extern int unregister_oom_notifier(struct notifier_block *nb);
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extern bool oom_killer_disabled;
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extern bool oom_killer_disable(void);
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extern void oom_killer_enable(void);
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extern struct task_struct *find_lock_task_mm(struct task_struct *p);
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static inline bool task_will_free_mem(struct task_struct *task)
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{
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/*
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* A coredumping process may sleep for an extended period in exit_mm(),
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* so the oom killer cannot assume that the process will promptly exit
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* and release memory.
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*/
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return (task->flags & PF_EXITING) &&
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!(task->signal->flags & SIGNAL_GROUP_COREDUMP);
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}
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/* sysctls */
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extern int sysctl_oom_dump_tasks;
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extern int sysctl_oom_kill_allocating_task;
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extern int sysctl_panic_on_oom;
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#endif /* _INCLUDE_LINUX_OOM_H */
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