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authorMichal Hocko <mhocko@suse.com>2017-07-12 14:36:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-12 16:26:03 -0700
commit91c63ecda75d3004da8ffd5d2590383e0ba47722 (patch)
tree4a8feb38b5ea9dc4178369cca725dc317dd56f9c /fs/xfs/kmem.h
parentdcda9b04713c3f6ff0875652924844fae28286ea (diff)
xfs: map KM_MAYFAIL to __GFP_RETRY_MAYFAIL
KM_MAYFAIL didn't have any suitable GFP_FOO counterpart until recently so it relied on the default page allocator behavior for the given set of flags. This means that small allocations actually never failed. Now that we have __GFP_RETRY_MAYFAIL flag which works independently on the allocation request size we can map KM_MAYFAIL to it. The allocator will try as hard as it can to fulfill the request but fails eventually if the progress cannot be made. It does so without triggering the OOM killer which can be seen as an improvement because KM_MAYFAIL users should be able to deal with allocation failures. Link: http://lkml.kernel.org/r/20170623085345.11304-4-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Alex Belits <alex.belits@cavium.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: David Daney <david.daney@cavium.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: NeilBrown <neilb@suse.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/xfs/kmem.h')
-rw-r--r--fs/xfs/kmem.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/xfs/kmem.h b/fs/xfs/kmem.h
index d6ea520162b2..4d85992d75b2 100644
--- a/fs/xfs/kmem.h
+++ b/fs/xfs/kmem.h
@@ -54,6 +54,16 @@ kmem_flags_convert(xfs_km_flags_t flags)
lflags &= ~__GFP_FS;
}
+ /*
+ * Default page/slab allocator behavior is to retry for ever
+ * for small allocations. We can override this behavior by using
+ * __GFP_RETRY_MAYFAIL which will tell the allocator to retry as long
+ * as it is feasible but rather fail than retry forever for all
+ * request sizes.
+ */
+ if (flags & KM_MAYFAIL)
+ lflags |= __GFP_RETRY_MAYFAIL;
+
if (flags & KM_ZERO)
lflags |= __GFP_ZERO;