diff options
| author |   Michal Hocko <mhocko@suse.com> | 2016-05-20 16:57:21 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-20 17:58:30 -0700 |
| commit | ec8d7c14ea14922fe21945b458a75e39f11dd832 (patch) | |
| tree | fe45cbd94518218d2be1288a812dbca8c1e01d95 /include/linux | |
| parent | mm, oom_reaper: hide oom reaped tasks from OOM killer more carefully (diff) | |
| download | linux-dev-ec8d7c14ea14922fe21945b458a75e39f11dd832.tar.xz linux-dev-ec8d7c14ea14922fe21945b458a75e39f11dd832.zip | |
mm, oom_reaper: do not mmput synchronously from the oom reaper context
Tetsuo has properly noted that mmput slow path might get blocked waiting
for another party (e.g. exit_aio waits for an IO). If that happens the
oom_reaper would be put out of the way and will not be able to process
next oom victim. We should strive for making this context as reliable
and independent on other subsystems as much as possible.
Introduce mmput_async which will perform the slow path from an async
(WQ) context. This will delay the operation but that shouldn't be a
problem because the oom_reaper has reclaimed the victim's address space
for most cases as much as possible and the remaining context shouldn't
bind too much memory anymore. The only exception is when mmap_sem
trylock has failed which shouldn't happen too often.
The issue is only theoretical but not impossible.
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/mm_types.h | 2 | ||||
| -rw-r--r-- | include/linux/sched.h | 5 |
2 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 1fda9c99ef95..d553855503e6 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -12,6 +12,7 @@ #include <linux/cpumask.h> #include <linux/uprobes.h> #include <linux/page-flags-layout.h> +#include <linux/workqueue.h> #include <asm/page.h> #include <asm/mmu.h> @@ -513,6 +514,7 @@ struct mm_struct { #ifdef CONFIG_HUGETLB_PAGE atomic_long_t hugetlb_usage; #endif + struct work_struct async_put_work; }; static inline void mm_init_cpumask(struct mm_struct *mm) diff --git a/include/linux/sched.h b/include/linux/sched.h index 40eabf176ce2..479e3cade7e9 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2730,6 +2730,11 @@ static inline void mmdrop(struct mm_struct * mm) /* mmput gets rid of the mappings and all user-space */ extern void mmput(struct mm_struct *); +/* same as above but performs the slow path from the async kontext. Can + * be called from the atomic context as well + */ +extern void mmput_async(struct mm_struct *); + /* Grab a reference to a task's mm, if it is not already going away */ extern struct mm_struct *get_task_mm(struct task_struct *task); /* |