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| author | Hugh Dickins <hugh.dickins@tiscali.co.uk> | 2009-09-21 17:02:27 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 07:17:33 -0700 |
| commit | 35451beecbd7c86ce3249d543594517a5fe9a0cd (patch) | |
| tree | e72759e6e6fcd142ab85c607a9b3dd3e1c016eed | |
| parent | a913e182ab9484308e870af37a14d372742d53b0 (diff) | |
| download | linux-35451beecbd7c86ce3249d543594517a5fe9a0cd.tar.gz linux-35451beecbd7c86ce3249d543594517a5fe9a0cd.tar.bz2 linux-35451beecbd7c86ce3249d543594517a5fe9a0cd.zip | |
ksm: unmerge is an origin of OOMs
Just as the swapoff system call allocates many pages of RAM to various
processes, perhaps triggering OOM, so "echo 2 >/sys/kernel/mm/ksm/run"
(unmerge) is liable to allocate many pages of RAM to various processes,
perhaps triggering OOM; and each is normally run from a modest admin
process (swapoff or shell), easily repeated until it succeeds.
So treat unmerge_and_remove_all_rmap_items() in the same way that we treat
try_to_unuse(): generalize PF_SWAPOFF to PF_OOM_ORIGIN, and bracket both
with that, to ask the OOM killer to kill them first, to prevent them from
spawning more and more OOM kills.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/sched.h | 2 | ||||
| -rw-r--r-- | mm/ksm.c | 2 | ||||
| -rw-r--r-- | mm/oom_kill.c | 2 | ||||
| -rw-r--r-- | mm/swapfile.c | 4 |
4 files changed, 6 insertions, 4 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 8f3e63cb33a6..899d7304d594 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1720,7 +1720,7 @@ extern cputime_t task_gtime(struct task_struct *p); #define PF_FROZEN 0x00010000 /* frozen for system suspend */ #define PF_FSTRANS 0x00020000 /* inside a filesystem transaction */ #define PF_KSWAPD 0x00040000 /* I am kswapd */ -#define PF_SWAPOFF 0x00080000 /* I am in swapoff */ +#define PF_OOM_ORIGIN 0x00080000 /* Allocating much memory to others */ #define PF_LESS_THROTTLE 0x00100000 /* Throttle me less: I clean memory */ #define PF_KTHREAD 0x00200000 /* I am a kernel thread */ #define PF_RANDOMIZE 0x00400000 /* randomize virtual address space */ @@ -1557,7 +1557,9 @@ static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr, if (ksm_run != flags) { ksm_run = flags; if (flags & KSM_RUN_UNMERGE) { + current->flags |= PF_OOM_ORIGIN; err = unmerge_and_remove_all_rmap_items(); + current->flags &= ~PF_OOM_ORIGIN; if (err) { ksm_run = KSM_RUN_STOP; count = err; diff --git a/mm/oom_kill.c b/mm/oom_kill.c index a7b2460e922b..da4c342f2641 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -79,7 +79,7 @@ unsigned long badness(struct task_struct *p, unsigned long uptime) /* * swapoff can easily use up all memory, so kill those first. */ - if (p->flags & PF_SWAPOFF) + if (p->flags & PF_OOM_ORIGIN) return ULONG_MAX; /* diff --git a/mm/swapfile.c b/mm/swapfile.c index 74f1102e8749..f1bf19daadc6 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1575,9 +1575,9 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) p->flags &= ~SWP_WRITEOK; spin_unlock(&swap_lock); - current->flags |= PF_SWAPOFF; + current->flags |= PF_OOM_ORIGIN; err = try_to_unuse(type); - current->flags &= ~PF_SWAPOFF; + current->flags &= ~PF_OOM_ORIGIN; if (err) { /* re-insert swap space back into swap_list */ |