linux-kernel - Re: [PATCH resend^2] mm: increase RECLAIM

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: <alpine.DEB.2.00.1104121719430.10966@chino.kir.corp.google.com>
Date:	Tue, 12 Apr 2011 17:22:21 -0700 (PDT)
From:	David Rientjes <rientjes@...gle.com>
To:	Dave Hansen <dave@...ux.vnet.ibm.com>
cc:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Christoph Lameter <cl@...ux.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Chris McDermott <lcm@...ux.vnet.ibm.com>
Subject: Re: [PATCH resend^2] mm: increase RECLAIM_DISTANCE to 30

On Mon, 11 Apr 2011, Dave Hansen wrote:

> > This patch raise zone_reclaim_mode threshold to 30. 30 don't have
> > specific meaning. but 20 mean one-hop QPI/Hypertransport and such
> > relatively cheap 2-4 socket machine are often used for tradiotional
> > server as above. The intention is, their machine don't use
> > zone_reclaim_mode.
> 
> I know specifically of pieces of x86 hardware that set the information
> in the BIOS to '21' *specifically* so they'll get the zone_reclaim_mode
> behavior which that implies.
> 

That doesn't seem like an argument against this patch, it's an improper 
configuration unless the remote memory access has a latency of 2.1x that 
of a local access between those two nodes.  If that's the case, then it's 
accurately following the ACPI spec and the VM has made its policy decision 
to enable zone_reclaim_mode as a result.  I'm surprised that they'd play 
with their BIOS to enable this by default, those, when it's an easily 
tunable sysctl.
--
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/