linux-kernel - Re: [PATCH][RF C/T/D] Unmapped page cache control

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]

Date:	Wed, 17 Mar 2010 09:49:11 +0100
From:	Christoph Hellwig <hch@....de>
To:	Avi Kivity <avi@...hat.com>
Cc:	Christoph Hellwig <hch@....de>, Chris Webb <chris@...chsys.com>,
	balbir@...ux.vnet.ibm.com,
	KVM development list <kvm@...r.kernel.org>,
	Rik van Riel <riel@...riel.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Kevin Wolf <kwolf@...hat.com>
Subject: Re: [PATCH][RF C/T/D] Unmapped page cache control - via boot parameter

On Tue, Mar 16, 2010 at 01:08:28PM +0200, Avi Kivity wrote:
> If the batch size is larger than the virtio queue size, or if there are 
> no flushes at all, then yes the huge write cache gives more opportunity 
> for reordering.  But we're already talking hundreds of requests here.

Yes.  And rememember those don't have to come from the same host.  Also
remember that we rather limit execssive reodering of O_DIRECT requests
in the I/O scheduler because they are "synchronous" type I/O while
we don't do that for pagecache writeback.

And we don't have unlimited virtio queue size, in fact it's quite
limited.
--
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/