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:	Fri, 03 Oct 2008 15:45:55 -0400
From:	Chris Mason <chris.mason@...cle.com>
To:	Dave Chinner <david@...morbit.com>
Cc:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	ext4 <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH] Improve buffered streaming write ordering

On Fri, 2008-10-03 at 09:43 +1000, Dave Chinner wrote:
> On Thu, Oct 02, 2008 at 11:48:56PM +0530, Aneesh Kumar K.V wrote:
> > On Thu, Oct 02, 2008 at 08:20:54AM -0400, Chris Mason wrote:
> > > On Wed, 2008-10-01 at 21:52 -0700, Andrew Morton wrote:
> > > For a 4.5GB streaming buffered write, this printk inside
> > > ext4_da_writepage shows up 37,2429 times in /var/log/messages.
> > > 
> > 
> > Part of that can happen due to shrink_page_list -> pageout -> writepagee
> > call back with lots of unallocated buffer_heads(blocks).
> 
> Quite frankly, a simple streaming buffered write should *never*
> trigger writeback from the LRU in memory reclaim.

The blktrace runs on ext4 didn't show kswapd doing any IO.  It isn't
clear if this is because ext4 did the redirty trick or if kswapd didn't
call writepage.

-chris


--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ