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| author |   Nicolas Boichat <drinkcat@chromium.org> | 2019-07-11 20:55:03 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-12 11:05:43 -0700 |
| commit | a9659476d4b391aec3f5357f176b63b9f8c46231 (patch) | |
| tree | bf4725f93941912a40c89b14cfd81131a2a37ad1 /mm/failslab.c | |
| parent | include/linux/pagemap.h: document trylock_page() return value (diff) | |
| download | wireguard-linux-a9659476d4b391aec3f5357f176b63b9f8c46231.tar.xz wireguard-linux-a9659476d4b391aec3f5357f176b63b9f8c46231.zip | |
mm/failslab.c: by default, do not fail allocations with direct reclaim only
When failslab was originally written, the intention of the
"ignore-gfp-wait" flag default value ("N") was to fail GFP_ATOMIC
allocations. Those were defined as (__GFP_HIGH), and the code would test
for __GFP_WAIT (0x10u).
However, since then, __GFP_WAIT was replaced by __GFP_RECLAIM
(___GFP_DIRECT_RECLAIM|___GFP_KSWAPD_RECLAIM), and GFP_ATOMIC is now
defined as (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM).
This means that when the flag is false, almost no allocation ever fails
(as even GFP_ATOMIC allocations contain ___GFP_KSWAPD_RECLAIM).
Restore the original intent of the code, by ignoring calls that directly
reclaim only (__GFP_DIRECT_RECLAIM), and thus, failing GFP_ATOMIC calls
again by default.
Link: http://lkml.kernel.org/r/20190520214514.81360-1-drinkcat@chromium.org
Fixes: 71baba4b92dc1fa1 ("mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM")
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/failslab.c')
| -rw-r--r-- | mm/failslab.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/failslab.c b/mm/failslab.c index ec5aad211c5b..f92fed91ac23 100644 --- a/mm/failslab.c +++ b/mm/failslab.c @@ -23,7 +23,8 @@ bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags) if (gfpflags & __GFP_NOFAIL) return false; - if (failslab.ignore_gfp_reclaim && (gfpflags & __GFP_RECLAIM)) + if (failslab.ignore_gfp_reclaim && + (gfpflags & __GFP_DIRECT_RECLAIM)) return false; if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB)) |