linux-kernel - Re: [PATCH] mm/vmstat: retrieve more accurate vmstat value

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

Message-ID: <20151126150330.GH7953@dhcp22.suse.cz>
Date:	Thu, 26 Nov 2015 16:03:30 +0100
From:	Michal Hocko <mhocko@...nel.org>
To:	Joonsoo Kim <iamjoonsoo.kim@....com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, Christoph Lameter <cl@...ux.com>,
	linux-mm@...ck.org
Subject: Re: [PATCH] mm/vmstat: retrieve more accurate vmstat value

On Thu 26-11-15 10:56:12, Joonsoo Kim wrote:
> On Wed, Nov 25, 2015 at 01:00:22PM +0100, Michal Hocko wrote:
> > On Tue 24-11-15 15:22:03, Joonsoo Kim wrote:
> > > When I tested compaction in low memory condition, I found that
> > > my benchmark is stuck in congestion_wait() at shrink_inactive_list().
> > > This stuck last for 1 sec and after then it can escape. More investigation
> > > shows that it is due to stale vmstat value. vmstat is updated every 1 sec
> > > so it is stuck for 1 sec.
> > 
> > Wouldn't it be sufficient to use zone_page_state_snapshot in
> > too_many_isolated?
> 
> Yes, it would work in this case. But, I prefer this patch because
> all zone_page_state() users get this benefit.

Just to make it clear, I am not against your patch in general. I am just
not sure it would help for too_many_isolated case where a significant
drift might occur on remote cpus as well so I am not really sure that is
appropriate for the issue you are seeing.
-- 
Michal Hocko
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/