From: Vlastimil Babka <vbabka@suse.cz>
To: Vladimir Davydov <vdavydov@virtuozzo.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Mel Gorman <mgorman@techsingularity.net>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] vmscan: do not throttle kthreads due to too_many_isolated
Date: Wed, 25 Nov 2015 16:45:13 +0100 [thread overview]
Message-ID: <5655D789.80201@suse.cz> (raw)
In-Reply-To: <1448465801-3280-1-git-send-email-vdavydov@virtuozzo.com>
On 11/25/2015 04:36 PM, Vladimir Davydov wrote:
> Block device drivers often hand off io request processing to kernel
> threads (example: device mapper). If such a thread calls kmalloc, it can
> dive into direct reclaim path and end up waiting for too_many_isolated
> to return false, blocking writeback. This can lead to a dead lock if the
Shouldn't such allocation lack __GFP_IO to prevent this and other kinds of
deadlocks? And/or have mempools? PF_KTHREAD looks like a big hammer to me that
will solve only one potential problem...
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WARNING: multiple messages have this Message-ID (diff)
From: Vlastimil Babka <vbabka@suse.cz>
To: Vladimir Davydov <vdavydov@virtuozzo.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Mel Gorman <mgorman@techsingularity.net>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] vmscan: do not throttle kthreads due to too_many_isolated
Date: Wed, 25 Nov 2015 16:45:13 +0100 [thread overview]
Message-ID: <5655D789.80201@suse.cz> (raw)
In-Reply-To: <1448465801-3280-1-git-send-email-vdavydov@virtuozzo.com>
On 11/25/2015 04:36 PM, Vladimir Davydov wrote:
> Block device drivers often hand off io request processing to kernel
> threads (example: device mapper). If such a thread calls kmalloc, it can
> dive into direct reclaim path and end up waiting for too_many_isolated
> to return false, blocking writeback. This can lead to a dead lock if the
Shouldn't such allocation lack __GFP_IO to prevent this and other kinds of
deadlocks? And/or have mempools? PF_KTHREAD looks like a big hammer to me that
will solve only one potential problem...
next prev parent reply other threads:[~2015-11-25 15:45 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-25 15:36 [PATCH] vmscan: do not throttle kthreads due to too_many_isolated Vladimir Davydov
2015-11-25 15:36 ` Vladimir Davydov
2015-11-25 15:45 ` Vlastimil Babka [this message]
2015-11-25 15:45 ` Vlastimil Babka
2015-11-25 16:27 ` Vladimir Davydov
2015-11-25 16:27 ` Vladimir Davydov
2015-11-26 8:16 ` Vladimir Davydov
2015-11-26 8:16 ` Vladimir Davydov
2015-11-27 12:50 ` Michal Hocko
2015-11-27 12:50 ` Michal Hocko
2015-11-27 13:40 ` Vladimir Davydov
2015-11-27 13:40 ` Vladimir Davydov
2015-11-27 15:01 ` Michal Hocko
2015-11-27 15:01 ` Michal Hocko
2015-12-01 11:25 ` Vladimir Davydov
2015-12-01 11:25 ` Vladimir Davydov
2015-12-02 13:52 ` Michal Hocko
2015-12-02 13:52 ` Michal Hocko
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