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author | Ying Han <yinghan@google.com> | 2010-10-26 14:21:23 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-26 16:52:05 -0700 |
commit | 3d5992d2ac7dc09aed8ab537cba074589f0f0a52 (patch) | |
tree | 0fbb51026e8aa13ddd7a6516c04471ceb97bc277 /include/linux/mm_types.h | |
parent | 0f4d208f1975f16f269134cee5f44c1f048581da (diff) | |
download | linux-stable-3d5992d2ac7dc09aed8ab537cba074589f0f0a52.tar.gz linux-stable-3d5992d2ac7dc09aed8ab537cba074589f0f0a52.tar.bz2 linux-stable-3d5992d2ac7dc09aed8ab537cba074589f0f0a52.zip |
oom: add per-mm oom disable count
It's pointless to kill a task if another thread sharing its mm cannot be
killed to allow future memory freeing. A subsequent patch will prevent
kills in such cases, but first it's necessary to have a way to flag a task
that shares memory with an OOM_DISABLE task that doesn't incur an
additional tasklist scan, which would make select_bad_process() an O(n^2)
function.
This patch adds an atomic counter to struct mm_struct that follows how
many threads attached to it have an oom_score_adj of OOM_SCORE_ADJ_MIN.
They cannot be killed by the kernel, so their memory cannot be freed in
oom conditions.
This only requires task_lock() on the task that we're operating on, it
does not require mm->mmap_sem since task_lock() pins the mm and the
operation is atomic.
[rientjes@google.com: changelog and sys_unshare() code]
[rientjes@google.com: protect oom_disable_count with task_lock in fork]
[rientjes@google.com: use old_mm for oom_disable_count in exec]
Signed-off-by: Ying Han <yinghan@google.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.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>
Diffstat (limited to 'include/linux/mm_types.h')
-rw-r--r-- | include/linux/mm_types.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index cb57d657ce4d..bb7288a782fd 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -310,6 +310,8 @@ struct mm_struct { #ifdef CONFIG_MMU_NOTIFIER struct mmu_notifier_mm *mmu_notifier_mm; #endif + /* How many tasks sharing this mm are OOM_DISABLE */ + atomic_t oom_disable_count; }; /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */ |