diff options
| author | Mel Gorman <mgorman@suse.de> | 2011-10-24 16:33:42 -0700 |
|---|---|---|
| committer | Dan Willemsen <dwillemsen@nvidia.com> | 2011-11-30 21:39:16 -0800 |
| commit | f4b5d78d60082b49879fceb6d3a7cb4b75e7c60b (patch) | |
| tree | d056d5c6b9fa3f332c80193bdace3c2e9d5edec6 | |
| parent | cd5997b848fc5081500ff7d7f00795511ad77bc0 (diff) | |
mm: avoid livelock on !__GFP_FS allocations
Under the following conditions, __alloc_pages_slowpath can loop
forever:
gfp_mask & __GFP_WAIT is true
gfp_mask & __GFP_FS is false
reclaim and compaction make no progress
order <= PAGE_ALLOC_COSTLY_ORDER
The gfp conditions are normally invalid, because !__GFP_FS
disables most of the reclaim methods that __GFP_WAIT would
wait for. However, these conditions happen very often during
suspend and resume, when pm_restrict_gfp_mask() effectively
converts all GFP_KERNEL allocations into __GFP_WAIT.
The oom killer is not run because gfp_mask & __GFP_FS is false,
but should_alloc_retry will always return true when order is less
than PAGE_ALLOC_COSTLY_ORDER. __alloc_pages_slowpath will
loop forever between the rebalance label and should_alloc_retry,
unless another thread happens to release enough pages to satisfy
the allocation.
Add a check to detect when PM has disabled __GFP_FS, and do not
retry if reclaim is not making any progress.
[taken from patch on lkml by Mel Gorman, commit message by ccross]
Change-Id: I864a24e9d9fd98bd0e3d6e9c1e85b6c1b766850e
Signed-off-by: Colin Cross <ccross@android.com>
| -rw-r--r-- | mm/page_alloc.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 41253539b32a..75cd8d74a1a5 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -127,6 +127,20 @@ void pm_restrict_gfp_mask(void) saved_gfp_mask = gfp_allowed_mask; gfp_allowed_mask &= ~GFP_IOFS; } + +static bool pm_suspending(void) +{ + if ((gfp_allowed_mask & GFP_IOFS) == GFP_IOFS) + return false; + return true; +} + +#else + +static bool pm_suspending(void) +{ + return false; +} #endif /* CONFIG_PM_SLEEP */ #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE @@ -2208,6 +2222,14 @@ rebalance: goto restart; } + + /* + * Suspend converts GFP_KERNEL to __GFP_WAIT which can + * prevent reclaim making forward progress without + * invoking OOM. Bail if we are suspending + */ + if (pm_suspending()) + goto nopage; } /* Check if we should retry the allocation */ |