linux-ext4 - Re: [PATCH v2] fs/ext4: increase parallelism in updating ext4 orphan list

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140415172522.GA13276@quack.suse.cz>
Date:	Tue, 15 Apr 2014 19:25:22 +0200
From:	Jan Kara <jack@...e.cz>
To:	Thavatchai Makphaibulchoke <thavatchai.makpahibulchoke@...com>
Cc:	Jan Kara <jack@...e.cz>, T Makphaibulchoke <tmac@...com>,
	tytso@....edu, adilger.kernel@...ger.ca,
	linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
	aswin@...com
Subject: Re: [PATCH v2] fs/ext4: increase parallelism in updating ext4 orphan
 list

On Tue 15-04-14 10:27:46, Thavatchai Makphaibulchoke wrote:
> On 04/14/2014 11:40 AM, Jan Kara wrote:
> >   Thanks for trying that out! Can you please send me a patch you have been
> > testing? Because it doesn't quite make sense to me why using i_mutex should
> > be worse than using hashed locks...
> >
> 
> Thanks again for the comments.
> 
> Since i_mutex is also used for serialization in other operations on an
> inode, in the case that the i_mutex is not held  using it for
> serialization could cause contention with other operations on the inode.
> As the number shows substantial instances of orphan add or delete calls
> without holding the i_mutex, I presume the performance degradation is due
> to the contention.
  I have checked the source and I didn't find many places where i_mutex was
not held. But maybe I'm wrong. That's why I wanted to see the patch where
you are using i_mutex instead of hashed mutexes and which didn't perform
good enough.

> As for the patch, could you please let me know if you need the patch
> using i_mutex or the patch I'm planning to submit.  If it's the latter,
> I'm thinking of go ahead and resubmit it.

								Honza
-- 
Jan Kara <jack@...e.cz>
SUSE Labs, CR
--
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