linux-kernel - Re: [PATCH] mm,vmscan: compact memory from kswapd when lots of memory free already

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Tue, 23 Feb 2016 10:39:56 -0500
From:	Rik van Riel <riel@...riel.com>
To:	Vlastimil Babka <vbabka@...e.cz>, linux-kernel@...r.kernel.org
Cc:	linux-mm@...ck.org, hannes@...xchg.org, akpm@...ux-foundation.org,
	mgorman@...e.de
Subject: Re: [PATCH] mm,vmscan: compact memory from kswapd when lots of
 memory free already

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 :)

-- 
All Rights Reversed.


Download attachment "signature.asc" of type "application/pgp-signature" (474 bytes)