]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm/failslab.c: by default, do not fail allocations with direct reclaim only
authorNicolas Boichat <drinkcat@chromium.org>
Fri, 12 Jul 2019 03:55:03 +0000 (20:55 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 12 Jul 2019 18:05:43 +0000 (11:05 -0700)
commita9659476d4b391aec3f5357f176b63b9f8c46231
treebf4725f93941912a40c89b14cfd81131a2a37ad1
parentf445884562dd8bc51eb4136bd21f014403d1813d
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>
mm/failslab.c