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| author |   David Rientjes <rientjes@google.com> | 2015-04-14 15:46:55 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2015-04-14 16:49:03 -0700 |
| commit | 4167e9b2cf10f8a4bcda0c713ddc8bb0a18e8187 (patch) | |
| tree | 744caf92870f2afa4facca7cdfbb6315e71b6592 /net | |
| parent | mm, mempolicy: migrate_to_node should only migrate to node (diff) | |
| download | linux-dev-4167e9b2cf10f8a4bcda0c713ddc8bb0a18e8187.tar.xz linux-dev-4167e9b2cf10f8a4bcda0c713ddc8bb0a18e8187.zip | |
mm: remove GFP_THISNODE
NOTE: this is not about __GFP_THISNODE, this is only about GFP_THISNODE.
GFP_THISNODE is a secret combination of gfp bits that have different
behavior than expected. It is a combination of __GFP_THISNODE,
__GFP_NORETRY, and __GFP_NOWARN and is special-cased in the page
allocator slowpath to fail without trying reclaim even though it may be
used in combination with __GFP_WAIT.
An example of the problem this creates: commit e97ca8e5b864 ("mm: fix
GFP_THISNODE callers and clarify") fixed up many users of GFP_THISNODE
that really just wanted __GFP_THISNODE. The problem doesn't end there,
however, because even it was a no-op for alloc_misplaced_dst_page(),
which also sets __GFP_NORETRY and __GFP_NOWARN, and
migrate_misplaced_transhuge_page(), where __GFP_NORETRY and __GFP_NOWAIT
is set in GFP_TRANSHUGE. Converting GFP_THISNODE to __GFP_THISNODE is a
no-op in these cases since the page allocator special-cases
__GFP_THISNODE && __GFP_NORETRY && __GFP_NOWARN.
It's time to just remove GFP_THISNODE entirely. We leave __GFP_THISNODE
to restrict an allocation to a local node, but remove GFP_THISNODE and
its obscurity. Instead, we require that a caller clear __GFP_WAIT if it
wants to avoid reclaim.
This allows the aforementioned functions to actually reclaim as they
should. It also enables any future callers that want to do
__GFP_THISNODE but also __GFP_NORETRY && __GFP_NOWARN to reclaim. The
rule is simple: if you don't want to reclaim, then don't set __GFP_WAIT.
Aside: ovs_flow_stats_update() really wants to avoid reclaim as well, so
it is unchanged.
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pravin Shelar <pshelar@nicira.com>
Cc: Jarno Rajahalme <jrajahalme@nicira.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/openvswitch/flow.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c index 50ec42f170a0..2dacc7b5af23 100644 --- a/net/openvswitch/flow.c +++ b/net/openvswitch/flow.c @@ -100,7 +100,9 @@ void ovs_flow_stats_update(struct sw_flow *flow, __be16 tcp_flags, new_stats = kmem_cache_alloc_node(flow_stats_cache, - GFP_THISNODE | + GFP_NOWAIT | + __GFP_THISNODE | + __GFP_NOWARN | __GFP_NOMEMALLOC, node); if (likely(new_stats)) { |