From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> To: mhocko@kernel.org, akpm@linux-foundation.org Cc: hannes@cmpxchg.org, mgorman@suse.de, dave.hansen@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.com Subject: Re: [PATCH 2/2] mm: warn about allocations which stall for too long Date: Thu, 29 Sep 2016 18:02:44 +0900 [thread overview] Message-ID: <201609291802.GFG81203.FLHtOMSJOVFFQO@I-love.SAKURA.ne.jp> (raw) In-Reply-To: <20160929084407.7004-3-mhocko@kernel.org> Michal Hocko wrote: > From: Michal Hocko <mhocko@suse.com> > > Currently we do warn only about allocation failures but small > allocations are basically nofail and they might loop in the page > allocator for a long time. Especially when the reclaim cannot make > any progress - e.g. GFP_NOFS cannot invoke the oom killer and rely on > a different context to make a forward progress in case there is a lot > memory used by filesystems. > > Give us at least a clue when something like this happens and warn about > allocations which take more than 10s. Print the basic allocation context > information along with the cumulative time spent in the allocation as > well as the allocation stack. Repeat the warning after every 10 seconds so > that we know that the problem is permanent rather than ephemeral. > > Signed-off-by: Michal Hocko <mhocko@suse.com> > --- > mm/page_alloc.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 969ffc97045b..73f60ad6315f 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3495,6 +3495,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > enum compact_result compact_result; > int compaction_retries = 0; > int no_progress_loops = 0; > + unsigned long alloc_start = jiffies; > + unsigned int stall_timeout = 10 * HZ; > > /* > * In the slowpath, we sanity check order to avoid ever trying to > @@ -3650,6 +3652,14 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_REPEAT)) > goto nopage; > > + /* Make sure we know about allocations which stall for too long */ > + if (time_after(jiffies, alloc_start + stall_timeout)) { > + warn_alloc(gfp_mask, I expect "gfp_mask & ~__GFP_NOWARN" rather than "gfp_mask" here. Otherwise, we can't get a clue for __GFP_NOWARN allocations. > + "page alloction stalls for %ums, order:%u\n", > + jiffies_to_msecs(jiffies-alloc_start), order); > + stall_timeout += 10 * HZ; > + } > + > if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags, > did_some_progress > 0, &no_progress_loops)) > goto retry; > -- > 2.9.3
WARNING: multiple messages have this Message-ID (diff)
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> To: mhocko@kernel.org, akpm@linux-foundation.org Cc: hannes@cmpxchg.org, mgorman@suse.de, dave.hansen@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.com Subject: Re: [PATCH 2/2] mm: warn about allocations which stall for too long Date: Thu, 29 Sep 2016 18:02:44 +0900 [thread overview] Message-ID: <201609291802.GFG81203.FLHtOMSJOVFFQO@I-love.SAKURA.ne.jp> (raw) In-Reply-To: <20160929084407.7004-3-mhocko@kernel.org> Michal Hocko wrote: > From: Michal Hocko <mhocko@suse.com> > > Currently we do warn only about allocation failures but small > allocations are basically nofail and they might loop in the page > allocator for a long time. Especially when the reclaim cannot make > any progress - e.g. GFP_NOFS cannot invoke the oom killer and rely on > a different context to make a forward progress in case there is a lot > memory used by filesystems. > > Give us at least a clue when something like this happens and warn about > allocations which take more than 10s. Print the basic allocation context > information along with the cumulative time spent in the allocation as > well as the allocation stack. Repeat the warning after every 10 seconds so > that we know that the problem is permanent rather than ephemeral. > > Signed-off-by: Michal Hocko <mhocko@suse.com> > --- > mm/page_alloc.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 969ffc97045b..73f60ad6315f 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3495,6 +3495,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > enum compact_result compact_result; > int compaction_retries = 0; > int no_progress_loops = 0; > + unsigned long alloc_start = jiffies; > + unsigned int stall_timeout = 10 * HZ; > > /* > * In the slowpath, we sanity check order to avoid ever trying to > @@ -3650,6 +3652,14 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_REPEAT)) > goto nopage; > > + /* Make sure we know about allocations which stall for too long */ > + if (time_after(jiffies, alloc_start + stall_timeout)) { > + warn_alloc(gfp_mask, I expect "gfp_mask & ~__GFP_NOWARN" rather than "gfp_mask" here. Otherwise, we can't get a clue for __GFP_NOWARN allocations. > + "page alloction stalls for %ums, order:%u\n", > + jiffies_to_msecs(jiffies-alloc_start), order); > + stall_timeout += 10 * HZ; > + } > + > if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags, > did_some_progress > 0, &no_progress_loops)) > goto retry; > -- > 2.9.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-09-29 9:02 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-09-23 8:15 [PATCH] mm: warn about allocations which stall for too long Michal Hocko 2016-09-23 8:15 ` Michal Hocko 2016-09-23 8:29 ` Hillf Danton 2016-09-23 8:29 ` Hillf Danton 2016-09-23 8:32 ` Michal Hocko 2016-09-23 8:32 ` Michal Hocko 2016-09-23 8:44 ` Hillf Danton 2016-09-23 8:44 ` Hillf Danton 2016-09-23 9:15 ` Michal Hocko 2016-09-23 9:15 ` Michal Hocko 2016-09-23 14:36 ` Tetsuo Handa 2016-09-23 14:36 ` Tetsuo Handa 2016-09-23 15:02 ` Michal Hocko 2016-09-23 15:02 ` Michal Hocko 2016-09-24 3:00 ` Tetsuo Handa 2016-09-24 3:00 ` Tetsuo Handa 2016-09-26 8:17 ` Michal Hocko 2016-09-26 8:17 ` Michal Hocko 2016-09-27 12:57 ` Tetsuo Handa 2016-09-27 12:57 ` Tetsuo Handa 2016-09-29 8:48 ` Michal Hocko 2016-09-29 8:48 ` Michal Hocko 2016-09-23 17:34 ` Dave Hansen 2016-09-23 17:34 ` Dave Hansen 2016-09-24 13:19 ` Balbir Singh 2016-09-24 13:19 ` Balbir Singh 2016-09-26 8:13 ` Michal Hocko 2016-09-26 8:13 ` Michal Hocko 2016-09-26 8:12 ` Michal Hocko 2016-09-26 8:12 ` Michal Hocko 2016-09-29 8:44 ` [PATCH 0/2] " Michal Hocko 2016-09-29 8:44 ` Michal Hocko 2016-09-29 8:44 ` [PATCH 1/2] mm: consolidate warn_alloc_failed users Michal Hocko 2016-09-29 8:44 ` Michal Hocko 2016-09-29 9:23 ` Vlastimil Babka 2016-09-29 9:23 ` Vlastimil Babka 2016-09-29 8:44 ` [PATCH 2/2] mm: warn about allocations which stall for too long Michal Hocko 2016-09-29 8:44 ` Michal Hocko 2016-09-29 9:02 ` Tetsuo Handa [this message] 2016-09-29 9:02 ` Tetsuo Handa 2016-09-29 9:10 ` Michal Hocko 2016-09-29 9:10 ` Michal Hocko
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