linux-kernel - Re: [RFC]block: add flush request at head

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:	Tue, 19 Apr 2011 09:07:04 +0800
From:	Shaohua Li <shaohua.li@...el.com>
To:	Christoph Hellwig <hch@...radead.org>
Cc:	Jens Axboe <jaxboe@...ionio.com>,
	lkml <linux-kernel@...r.kernel.org>,
	Tejun Heo <htejun@...il.com>, "Shi, Alex" <alex.shi@...el.com>,
	"Chen, Tim C" <tim.c.chen@...el.com>
Subject: Re: [RFC]block: add flush request at head

On Mon, 2011-04-18 at 17:26 +0800, Christoph Hellwig wrote:
> On Mon, Apr 18, 2011 at 10:08:52AM +0200, Jens Axboe wrote:
> > Might be worth adding something for this special case, seems like the
> > NCQ restrictions will continue to be around forever (or a long time, at
> > least).
> 
> I heared people are working on adding a queued FLUSH to the standard,
> but it's going to take a long time for it to get into real life systems.
> 
> What would help now is allowing libata to actually use the FUA bit,
> given that every common disk and controller supports it these days.
> 
> Shaohua, does adding a
> 
> 	libata.fua = 1
> 
> to the kernel command line help your benchmark in any way?  It should
> if you flushes are mostly from journal writes, but not from fsync
> that didn't change any metadata.
This is a workload with fsync. I tested libata.fua=1, but nothing changed.

I also hacked the code when we proceed queue running flush list, also
proceed queue pending flush list, which doesn't change correctness for
sata. This improved a little, around 5%, but doesn't recover the whole
regression. so I still need add the flush request at queue head.

Thanks,
Shaohua


--
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/