From: Rik van Riel <riel@surriel.com>
To: Vlastimil Babka <vbabka@suse.cz>, linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, hannes@cmpxchg.org,
akpm@linux-foundation.org, mgorman@suse.de
Subject: Re: [PATCH] mm,vmscan: compact memory from kswapd when lots of memory free already
Date: Tue, 23 Feb 2016 10:39:56 -0500 [thread overview]
Message-ID: <1456241996.7716.34.camel@surriel.com> (raw)
In-Reply-To: <56CC23F7.8010709@suse.cz>
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On Tue, 2016-02-23 at 10:18 +0100, Vlastimil Babka wrote:
> On 02/23/2016 04:50 AM, Rik van Riel wrote:
> > If kswapd is woken up for a higher order allocation, for example
> > from alloc_skb, but the system already has lots of memory free,
> > kswapd_shrink_zone will rightfully decide kswapd should not free
> > any more memory.
> >
> > However, at that point kswapd should proceed to compact memory, on
> > behalf of alloc_skb or others.
> >
> > Currently kswapd will only compact memory if it first freed memory,
> > leading kswapd to never compact memory when there is already lots
> > of
> > memory free.
> >
> > On my home system, that lead to kswapd occasionally using up to 5%
> > CPU time, with many man wakeups from alloc_skb, and kswapd never
> > doing anything to relieve the situation that caused it to be woken
> > up.
>
> Hi,
>
> I've proposed replacing kswapd compaction with kcompactd, so this
> hunk
> is gone completely in mmotm. This imperfect comparison was indeed one
> of
> the things I've noted, but it's not all:
>
> http://marc.info/?l=linux-kernel&m=145493881908394&w=2
Never mind my patch, then. Your solution is nicer,
and already in -mm :)
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prev parent reply other threads:[~2016-02-23 15:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-23 3:50 [PATCH] mm,vmscan: compact memory from kswapd when lots of memory free already Rik van Riel
2016-02-23 3:50 ` Rik van Riel
2016-02-23 9:18 ` Vlastimil Babka
2016-02-23 9:18 ` Vlastimil Babka
2016-02-23 15:39 ` Rik van Riel [this message]
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