linux-ext4 - Re: [PATCH 2/8 v3] ext4: add operations on extent status tree

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, 9 Nov 2012 10:22:55 +0800
From:	Zheng Liu <gnehzuil.liu@...il.com>
To:	Theodore Ts'o <tytso@....edu>
Cc:	linux-ext4@...r.kernel.org, jeff.liu@...cle.com, hughd@...gle.com,
	xiaoqiangnk@...il.com, achender@...ux.vnet.ibm.com,
	lczerner@...hat.com, Zheng Liu <wenqing.lz@...bao.com>
Subject: Re: [PATCH 2/8 v3] ext4: add operations on extent status tree

On Thu, Nov 08, 2012 at 06:21:23PM -0500, Theodore Ts'o wrote:
> On Fri, Oct 26, 2012 at 09:23:39PM +0800, Zheng Liu wrote:
> > + * 3. performance analysis
> > + *   --	overhead
> > + *	1. Apart from operations on a delayed extent tree, we need to
> > + *	down_write(inode->i_data_sem) in delayed write path to maintain delayed
> > + *	extent tree, this can have impact on parallel read-write and write-write
> 
> Hi Zheng,
> 
> I can fix this up, before I finalize your commit, but I just want to
> check.  I believe this comment is out of date --- we are now using a
> r/w spinlock, i_es_lock, yes?  Since we never hold the spinlock for
> very long, I would be surprised if this is going to be a scalability
> bottleneck (too bad Eric doesn't have access to the big SMP machine
> that he used to use to help us do our scalability testing, so we could
> check to be sure).

Hi Ted,

Oops, it is my fault.  Indeed it needs to be replaced with i_es_lock.  I
can do some tests in a server which has 16 cores, but I am afraid that
it is not so big as you thought.  I am willing to run Eric's tests to 
ensure that there is no any scalability problem.
 
Regards,
Zheng
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html