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d003f371b2
oom_kill.c assumes that PF_EXITING task should exit and free the memory soon. This is wrong in many ways and one important case is the coredump. A task can sleep in exit_mm() "forever" while the coredumping sub-thread can need more memory. Change the PF_EXITING checks to take SIGNAL_GROUP_COREDUMP into account, we add the new trivial helper for that. Note: this is only the first step, this patch doesn't try to solve other problems. The SIGNAL_GROUP_COREDUMP check is obviously racy, a task can participate in coredump after it was already observed in PF_EXITING state, so TIF_MEMDIE (which also blocks oom-killer) still can be wrongly set. fatal_signal_pending() can be true because of SIGNAL_GROUP_COREDUMP so out_of_memory() and mem_cgroup_out_of_memory() shouldn't blindly trust it. And even the name/usage of the new helper is confusing, an exiting thread can only free its ->mm if it is the only/last task in thread group. [akpm@linux-foundation.org: add comment] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
111 lines
3.0 KiB
C
111 lines
3.0 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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* 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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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 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 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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extern bool oom_zonelist_trylock(struct zonelist *zonelist, gfp_t gfp_flags);
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extern void oom_zonelist_unlock(struct zonelist *zonelist, gfp_t gfp_flags);
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extern void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
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int order, const nodemask_t *nodemask);
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extern enum oom_scan_t oom_scan_process_thread(struct task_struct *task,
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unsigned long totalpages, const nodemask_t *nodemask,
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bool force_kill);
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extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
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int order, nodemask_t *mask, bool force_kill);
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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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static inline void oom_killer_disable(void)
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{
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oom_killer_disabled = true;
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}
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static inline void oom_killer_enable(void)
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{
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oom_killer_disabled = false;
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}
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static inline bool oom_gfp_allowed(gfp_t gfp_mask)
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{
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return (gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY);
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}
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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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