Re: [PATCH] mm: don't warn about allocations which stall for too long

From: Michal Hocko <mhocko@kernel.org>
To: peter enderborg <peter.enderborg@sonymobile.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	akpm@linux-foundation.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Mel Gorman <mgorman@suse.de>, Petr Mladek <pmladek@suse.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	"yuwang.yuwang" <yuwang.yuwang@alibaba-inc.com>
Subject: Re: [PATCH] mm: don't warn about allocations which stall for too long
Date: Thu, 9 Nov 2017 09:52:49 +0100	[thread overview]
Message-ID: <20171109085249.guihvx5tzm77u3qk@dhcp22.suse.cz> (raw)
In-Reply-To: <91bdbdea-3f33-b7c0-8345-d0fa8c7f1cf1@sonymobile.com>

[Please try to trim the context you are replying to]

On Wed 08-11-17 11:30:23, peter enderborg wrote:
[...]
> What about the idea to keep the function, but instead of printing only do a trace event.

I am not sure. I would rather see a tracepoint to mark the allocator
entry. This would allow both 1) measuring the allocation latency (to
compare it to the trace_mm_page_alloc and 2) check for stalls with
arbitrary user defined timeout (just print all allocations which haven't
passed trace_mm_page_alloc for the given amount of time).
-- 
Michal Hocko
SUSE Labs