linux-kernel - Re: [PATCHSET block#for-2.6.36-post] block: replace barrier with sequenced flush

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:	Mon, 30 Aug 2010 12:04:56 +0200
From:	Hannes Reinecke <hare@...e.de>
To:	Christoph Hellwig <hch@....de>
Cc:	Jens Axboe <jaxboe@...ionio.com>,
	Ric Wheeler <rwheeler@...hat.com>, Tejun Heo <tj@...nel.org>,
	"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
	"linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
	"linux-ide@...r.kernel.org" <linux-ide@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-raid@...r.kernel.org" <linux-raid@...r.kernel.org>,
	"James.Bottomley@...e.de" <James.Bottomley@...e.de>,
	"tytso@....edu" <tytso@....edu>,
	"chris.mason@...cle.com" <chris.mason@...cle.com>,
	"swhiteho@...hat.com" <swhiteho@...hat.com>,
	"konishi.ryusuke@....ntt.co.jp" <konishi.ryusuke@....ntt.co.jp>,
	"dm-devel@...hat.com" <dm-devel@...hat.com>,
	"vst@...b.net" <vst@...b.net>, "jack@...e.cz" <jack@...e.cz>
Subject: Re: [PATCHSET block#for-2.6.36-post] block: replace barrier with
 sequenced flush

Christoph Hellwig wrote:
> On Mon, Aug 23, 2010 at 04:01:15PM +0200, Jens Axboe wrote:
>> The problem purely exists on arrays that report write back cache enabled
>> AND don't implement SYNC_CACHE as a noop. Do any of them exist, or are
>> they purely urban legend?
> 
> I haven't seen it.  I don't care particularly about this case, but once
> it a while people want to disable flushing for testing or because they
> really don't care.
> 
aacraid for one falls into this category.
SYNC_CACHE is no-oped in the driver. Otherwise you get a _HUGE_
performance loss.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@...e.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
--
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/