From: Thavatchai Makphaibulchoke <thavatchai.makpahibulchoke@hp.com>
To: Theodore Ts'o <tytso@mit.edu>, Andreas Dilger <adilger@dilger.ca>
Cc: T Makphaibulchoke <tmac@hp.com>,
Al Viro <viro@zeniv.linux.org.uk>,
"linux-ext4@vger.kernel.org List" <linux-ext4@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org Devel"
<linux-fsdevel@vger.kernel.org>,
aswin@hp.com, Linus Torvalds <torvalds@linux-foundation.org>,
aswin_proj@lists.hp.com
Subject: Re: [PATCH v3 0/2] ext4: increase mbcache scalability
Date: Tue, 10 Sep 2013 17:10:13 +0000 [thread overview]
Message-ID: <522F5275.7050001@hp.com> (raw)
In-Reply-To: <20130910210250.GH29237@thunk.org>
On 09/10/2013 09:02 PM, Theodore Ts'o wrote:
> On Tue, Sep 10, 2013 at 02:47:33PM -0600, Andreas Dilger wrote:
>> I agree that SELinux is enabled on enterprise distributions by default,
>> but I'm also interested to know how much overhead this imposes. I would
>> expect that writing large external xattrs for each file would have quite
>> a significant performance overhead that should not be ignored. Reducing
>> the mbcache overhead is good, but eliminating it entirely is better.
>
> I was under the impression that using a 256 byte inode (which gives a
> bit over 100 bytes worth of xattr space) was plenty for SELinux. If
> it turns out that SELinux's use of xattrs have gotten especially
> piggy, then we may need to revisit the recommended inode size for
> those systems who insist on using SELinux... even if we eliminate the
> overhead associated with mbcache, the fact that files are requiring a
> separate xattr is going to seriously degrade performance.
>
> - Ted
>
Thank you Andreas and Ted for the explanations and comments. Yes, I see both of your points now. Though we may reduce the mbcache overhead, due to the overhead of additional xattr I/O it would be better to provide some data to help users or distros to determine whether they will be better off completely disabling SELinux or increasing the inode size. I will go ahead and run the suggested experiments and get back with the results.
Thanks,
Mak.
next prev parent reply other threads:[~2013-09-10 17:10 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-18 0:55 [PATCH 0/2] ext4: increase mbcache scalability T Makphaibulchoke
2013-08-22 15:54 ` [PATCH v2 " T Makphaibulchoke
2013-08-22 15:54 ` [PATCH v2 1/2] mbcache: decoupling the locking of local from global data T Makphaibulchoke
2013-08-22 16:53 ` Linus Torvalds
2013-08-22 15:33 ` Thavatchai Makphaibulchoke
2013-08-22 15:54 ` [PATCH v2 2/2] ext4: each filesystem creates and uses its own mc_cache T Makphaibulchoke
2014-01-24 18:31 ` [PATCH v4 0/3] ext4: increase mbcache scalability T Makphaibulchoke
2014-01-24 18:31 ` [PATCH v4 1/3] fs/mbcache.c change block and index hash chain to hlist_bl_node T Makphaibulchoke
2014-01-24 18:31 ` [PATCH v4 2/3] mbcache: decoupling the locking of local from global data T Makphaibulchoke
2014-01-24 18:31 ` [PATCH v4 3/3] ext4: each filesystem creates and uses its own mc_cache T Makphaibulchoke
2014-01-24 21:38 ` [PATCH v4 0/3] ext4: increase mbcache scalability Andi Kleen
2014-01-25 1:13 ` Thavatchai Makphaibulchoke
2014-01-25 6:09 ` Andreas Dilger
2014-01-27 12:27 ` Thavatchai Makphaibulchoke
2014-02-09 19:46 ` Thavatchai Makphaibulchoke
2014-02-11 19:58 ` Thavatchai Makphaibulchoke
2014-02-13 2:01 ` Andreas Dilger
2013-09-04 16:39 ` [PATCH v3 0/2] " T Makphaibulchoke
2013-09-04 16:39 ` [PATCH v3 1/2] mbcache: decoupling the locking of local from global data T Makphaibulchoke
2013-10-30 13:27 ` Theodore Ts'o
2013-10-30 14:42 ` Theodore Ts'o
2013-10-30 17:32 ` Thavatchai Makphaibulchoke
2013-09-04 16:39 ` [PATCH v3 2/2] ext4: each filesystem creates and uses its own mb_cache T Makphaibulchoke
2013-10-30 14:30 ` Theodore Ts'o
2013-09-04 20:00 ` [PATCH v3 0/2] ext4: increase mbcache scalability Andreas Dilger
2013-09-04 15:33 ` Thavatchai Makphaibulchoke
2013-09-05 15:22 ` Thavatchai Makphaibulchoke
2013-09-05 2:35 ` Theodore Ts'o
2013-09-05 9:49 ` Thavatchai Makphaibulchoke
2013-09-06 5:10 ` Andreas Dilger
2013-09-06 12:23 ` Thavatchai Makphaibulchoke
2013-09-10 20:47 ` Andreas Dilger
2013-09-10 21:02 ` Theodore Ts'o
2013-09-10 17:10 ` Thavatchai Makphaibulchoke [this message]
2013-09-11 3:13 ` Eric Sandeen
2013-09-11 11:30 ` Theodore Ts'o
2013-09-11 16:49 ` Eric Sandeen
2013-09-11 19:33 ` Eric Sandeen
2013-09-11 20:32 ` David Lang
2013-09-11 20:48 ` Eric Sandeen
2013-09-11 21:25 ` Theodore Ts'o
2013-09-11 20:36 ` Thavatchai Makphaibulchoke
2013-09-12 3:42 ` Eric Sandeen
2014-02-20 18:37 ` [PATCH V5 0/3] " T Makphaibulchoke
2014-02-20 18:37 ` [PATCH V5 1/3] fs/mbcache.c change block and index hash chain to hlist_bl_node T Makphaibulchoke
2014-02-20 18:37 ` [PATCH V5 2/3] mbcache: decoupling the locking of local from global data T Makphaibulchoke
2014-02-20 18:37 ` [PATCH V5 3/3] ext4: each filesystem creates and uses its own mb_cache T Makphaibulchoke
2014-03-12 16:19 ` [PATCH v5 RESEND 0/3] ext4: increase mbcache scalability T Makphaibulchoke
2014-03-12 16:19 ` [PATCH v5 RESEND 1/3] fs/mbcache.c change block and index hash chain to hlist_bl_node T Makphaibulchoke
2014-03-12 16:19 ` [PATCH v5 RESEND 2/3] mbcache: decoupling the locking of local from global data T Makphaibulchoke
2014-03-12 16:19 ` [PATCH v5 RESEND 3/3] ext4: each filesystem creates and uses its own mb_cache T Makphaibulchoke
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