From: Mel Gorman <mgorman@techsingularity.net>
To: zhouxianrong@huawei.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, viro@zeniv.linux.org.uk,
mingo@redhat.com, peterz@infradead.org, hannes@cmpxchg.org,
vbabka@suse.cz, mhocko@suse.com, vdavydov.dev@gmail.com,
minchan@kernel.org, riel@redhat.com, zhouxiyu@huawei.com,
zhangshiming5@huawei.com, won.ho.park@huawei.com,
tuxiaobing@huawei.com
Subject: Re: [PATCH] bdi flusher should not be throttled here when it fall into buddy slow path
Date: Tue, 18 Oct 2016 10:59:12 +0100 [thread overview]
Message-ID: <20161018095912.GD22174@techsingularity.net> (raw)
In-Reply-To: <1476774765-21130-1-git-send-email-zhouxianrong@huawei.com>
On Tue, Oct 18, 2016 at 03:12:45PM +0800, zhouxianrong@huawei.com wrote:
> From: z00281421 <z00281421@notesmail.huawei.com>
>
> bdi flusher may enter page alloc slow path due to writepage and kmalloc.
> in that case the flusher as a direct reclaimer should not be throttled here
> because it can not to reclaim clean file pages or anaonymous pages
> for next moment; furthermore writeback rate of dirty pages would be
> slow down and other direct reclaimers and kswapd would be affected.
> bdi flusher should be iosceduled by get_request rather than here.
>
> Signed-off-by: z00281421 <z00281421@notesmail.huawei.com>
What does this patch do that PF_LESS_THROTTLE is not doing already if
there is an underlying BDI?
There have been a few patches like this recently that look like they might
do something useful but are subtle. They really should be accompanied by
a test case and data showing they either fix a functional issue (machine
livelocking due to writeback not making progress) or a performance issue.
--
Mel Gorman
SUSE Labs
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WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@techsingularity.net>
To: zhouxianrong@huawei.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, viro@zeniv.linux.org.uk,
mingo@redhat.com, peterz@infradead.org, hannes@cmpxchg.org,
vbabka@suse.cz, mhocko@suse.com, vdavydov.dev@gmail.com,
minchan@kernel.org, riel@redhat.com, zhouxiyu@huawei.com,
zhangshiming5@huawei.com, won.ho.park@huawei.com,
tuxiaobing@huawei.com
Subject: Re: [PATCH] bdi flusher should not be throttled here when it fall into buddy slow path
Date: Tue, 18 Oct 2016 10:59:12 +0100 [thread overview]
Message-ID: <20161018095912.GD22174@techsingularity.net> (raw)
In-Reply-To: <1476774765-21130-1-git-send-email-zhouxianrong@huawei.com>
On Tue, Oct 18, 2016 at 03:12:45PM +0800, zhouxianrong@huawei.com wrote:
> From: z00281421 <z00281421@notesmail.huawei.com>
>
> bdi flusher may enter page alloc slow path due to writepage and kmalloc.
> in that case the flusher as a direct reclaimer should not be throttled here
> because it can not to reclaim clean file pages or anaonymous pages
> for next moment; furthermore writeback rate of dirty pages would be
> slow down and other direct reclaimers and kswapd would be affected.
> bdi flusher should be iosceduled by get_request rather than here.
>
> Signed-off-by: z00281421 <z00281421@notesmail.huawei.com>
What does this patch do that PF_LESS_THROTTLE is not doing already if
there is an underlying BDI?
There have been a few patches like this recently that look like they might
do something useful but are subtle. They really should be accompanied by
a test case and data showing they either fix a functional issue (machine
livelocking due to writeback not making progress) or a performance issue.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2016-10-18 9:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-18 7:12 [PATCH] bdi flusher should not be throttled here when it fall into buddy slow path zhouxianrong
2016-10-18 7:12 ` zhouxianrong
2016-10-18 9:34 ` Hillf Danton
2016-10-18 9:34 ` Hillf Danton
2016-10-18 9:59 ` Mel Gorman [this message]
2016-10-18 9:59 ` Mel Gorman
2016-10-18 11:08 ` zhouxianrong
2016-10-18 11:08 ` zhouxianrong
2016-10-18 11:42 ` Michal Hocko
2016-10-18 11:42 ` Michal Hocko
2016-10-20 12:38 ` zhouxianrong
2016-10-20 12:38 ` zhouxianrong
2016-10-20 13:05 ` Mika Penttilä
2016-10-20 13:05 ` Mika Penttilä
2016-10-20 13:28 ` Michal Hocko
2016-10-20 13:28 ` Michal Hocko
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