From: "Hillf Danton" <hillf.zj@alibaba-inc.com>
To: "'Shakeel Butt'" <shakeelb@google.com>,
"'Johannes Weiner'" <hannes@cmpxchg.org>,
"'Mel Gorman'" <mgorman@techsingularity.net>,
"'Michal Hocko'" <mhocko@suse.com>,
"'Vlastimil Babka'" <vbabka@suse.cz>,
"'Andrew Morton'" <akpm@linux-foundation.org>
Cc: "'Jia He'" <hejianet@gmail.com>, <linux-mm@kvack.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] mm: fix condition for throttle_direct_reclaim
Date: Tue, 14 Mar 2017 11:04:42 +0800 [thread overview]
Message-ID: <09b201d29c6f$babfa370$303eea50$@alibaba-inc.com> (raw)
In-Reply-To: <20170313221920.7881-1-shakeelb@google.com>
On March 14, 2017 6:19 AM Shakeel Butt wrote:
>
> Recently kswapd has been modified to give up after MAX_RECLAIM_RETRIES
> number of unsucessful iterations. Before going to sleep, kswapd thread
> will unconditionally wakeup all threads sleeping on pfmemalloc_wait.
> However the awoken threads will recheck the watermarks and wake the
> kswapd thread and sleep again on pfmemalloc_wait. There is a chance
> of continuous back and forth between kswapd and direct reclaiming
> threads if the kswapd keep failing and thus defeat the purpose of
> adding backoff mechanism to kswapd. So, add kswapd_failures check
> on the throttle_direct_reclaim condition.
>
> Signed-off-by: Shakeel Butt <shakeelb@google.com>
> Suggested-by: Michal Hocko <mhocko@suse.com>
> Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
> ---
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
WARNING: multiple messages have this Message-ID (diff)
From: "Hillf Danton" <hillf.zj@alibaba-inc.com>
To: 'Shakeel Butt' <shakeelb@google.com>,
'Johannes Weiner' <hannes@cmpxchg.org>,
'Mel Gorman' <mgorman@techsingularity.net>,
'Michal Hocko' <mhocko@suse.com>,
'Vlastimil Babka' <vbabka@suse.cz>,
'Andrew Morton' <akpm@linux-foundation.org>
Cc: 'Jia He' <hejianet@gmail.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] mm: fix condition for throttle_direct_reclaim
Date: Tue, 14 Mar 2017 11:04:42 +0800 [thread overview]
Message-ID: <09b201d29c6f$babfa370$303eea50$@alibaba-inc.com> (raw)
In-Reply-To: <20170313221920.7881-1-shakeelb@google.com>
On March 14, 2017 6:19 AM Shakeel Butt wrote:
>
> Recently kswapd has been modified to give up after MAX_RECLAIM_RETRIES
> number of unsucessful iterations. Before going to sleep, kswapd thread
> will unconditionally wakeup all threads sleeping on pfmemalloc_wait.
> However the awoken threads will recheck the watermarks and wake the
> kswapd thread and sleep again on pfmemalloc_wait. There is a chance
> of continuous back and forth between kswapd and direct reclaiming
> threads if the kswapd keep failing and thus defeat the purpose of
> adding backoff mechanism to kswapd. So, add kswapd_failures check
> on the throttle_direct_reclaim condition.
>
> Signed-off-by: Shakeel Butt <shakeelb@google.com>
> Suggested-by: Michal Hocko <mhocko@suse.com>
> Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
> ---
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
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next prev parent reply other threads:[~2017-03-14 3:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-13 22:19 [PATCH v2] mm: fix condition for throttle_direct_reclaim Shakeel Butt
2017-03-13 22:19 ` Shakeel Butt
2017-03-14 3:04 ` Hillf Danton [this message]
2017-03-14 3:04 ` Hillf Danton
2017-03-14 8:16 ` Michal Hocko
2017-03-14 8:16 ` Michal Hocko
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