Messages in this thread Patch in this message | | | From | mhocko@kernel ... | Subject | [PATCH 2/2] btrfs: use __GFP_NOFAIL in alloc_btrfs_bio | Date | Wed, 19 Aug 2015 14:17:41 +0200 |
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From: Michal Hocko <mhocko@suse.com>
alloc_btrfs_bio relies on GFP_NOFS allocation when committing the transaction but this allocation context is rather weak wrt. reclaim capabilities. The page allocator currently tries hard to not fail these allocations if they are small (<=PAGE_ALLOC_COSTLY_ORDER) but it can still fail if the _current_ process is the OOM killer victim. Moreover there is an attempt to move away from the default no-fail behavior and allow these allocation to fail more eagerly. This would lead to:
[ 37.928625] kernel BUG at fs/btrfs/extent_io.c:4045
which is clearly undesirable and the nofail behavior should be explicit if the allocation failure cannot be tolerated.
Signed-off-by: Michal Hocko <mhocko@suse.com> --- fs/btrfs/volumes.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 53af23f2c087..42b9949dd71d 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4914,9 +4914,7 @@ static struct btrfs_bio *alloc_btrfs_bio(int total_stripes, int real_stripes) * and the stripes */ sizeof(u64) * (total_stripes), - GFP_NOFS); - if (!bbio) - return NULL; + GFP_NOFS|__GFP_NOFAIL); atomic_set(&bbio->error, 0); atomic_set(&bbio->refs, 1); -- 2.5.0
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