linux-kernel - Re: [patch 0/7] cpuset writeback throttling

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: <20081105103123.66dcb902.kamezawa.hiroyu@jp.fujitsu.com>
Date:	Wed, 5 Nov 2008 10:31:23 +0900
From:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Christoph Lameter <cl@...ux-foundation.org>, npiggin@...e.de,
	dfults@....com, linux-kernel@...r.kernel.org, rientjes@...gle.com,
	containers@...ts.osdl.org, menage@...gle.com
Subject: Re: [patch 0/7] cpuset writeback throttling

On Tue, 4 Nov 2008 15:36:10 -0800
Andrew Morton <akpm@...ux-foundation.org> wrote:

> On Tue, 4 Nov 2008 16:52:48 -0600 (CST)
> Christoph Lameter <cl@...ux-foundation.org> wrote:
> 
> > On Tue, 4 Nov 2008, Andrew Morton wrote:
> > 
> > > To fix this with a memcg-based throttling, the operator would need to
> > > be able to create memcg's which have pages only from particular nodes.
> > > (That's a bit indirect relative to what they want to do, but is
> > > presumably workable).
> > 
> > The system would need to have the capability to find the memcg groups that 
> > have dirty pages for a certain inode. Files are not constrained to nodes 
> > or memcg groups.
> 
> Ah, we're talking about different things.
> 
> In a memcg implementation what we would implement is "throttle
> page-dirtying tasks in this memcg when the memcg's dirty memory reaches
> 40% of its total".
> 
yes. Andrea posted that.


> But that doesn't solve the problem which this patchset is trying to
> solve, which is "don't let all the memory in all this group of nodes
> get dirty".
> 
yes. but this patch doesn't help the case you mentioned below.

> 
> Yes?  Someone help me out here.  I don't yet have my head around the
> overlaps and incompatibilities here.  Perhaps the containers guys will
> wake up and put their thinking caps on?
> 
> 
> 
> What happens if cpuset A uses nodes 0,1,2,3,4,5,6,7,8,9 and cpuset B
> uses nodes 0,1?  Can activity in cpuset A cause ooms in cpuset B?
> 
For help this, per-node-dirty-ratio-throttoling is necessary.

Shouldn't we just have a new parameter as /proc/sys/vm/dirty_ratio_per_node.

/proc/sys/vm/dirty_ratio works for throttling the whole system dirty pages.
/proc/sys/vm/dirty_ratio_per_node works for throttling dirty pages in a node.

Implementation will not be difficult and works enough against OOM.

Thanks,
-Kame








--
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/