mm: page_alloc: __GFP_NOWARN shouldn't suppress stall warnings

__GFP_NOWARN, which is usually added to avoid warnings from callsites
that expect to fail and have fallbacks, currently also suppresses
allocation stall warnings.  These trigger when an allocation is stuck
inside the allocator for 10 seconds or longer.

But there is no class of allocations that can get legitimately stuck in
the allocator for this long.  This always indicates a problem.

Always emit stall warnings.  Restrict __GFP_NOWARN to alloc failures.

Link: http://lkml.kernel.org/r/20170125181150.GA16398@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Weiner 2017-05-03 14:53:48 -07:00 committed by Linus Torvalds
parent e716f2eb24
commit 8225196341

View file

@ -3751,7 +3751,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
/* Make sure we know about allocations which stall for too long */
if (time_after(jiffies, alloc_start + stall_timeout)) {
warn_alloc(gfp_mask, ac->nodemask,
warn_alloc(gfp_mask & ~__GFP_NOWARN, ac->nodemask,
"page allocation stalls for %ums, order:%u",
jiffies_to_msecs(jiffies-alloc_start), order);
stall_timeout += 10 * HZ;