From: Thavatchai Makphaibulchoke <thavatchai.makpahibulchoke@hp.com>
To: Andreas Dilger <adilger@dilger.ca>, Andi Kleen <andi@firstfloor.org>
Cc: T Makphaibulchoke <tmac@hp.com>,
"viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
"tytso@mit.edu" <tytso@mit.edu>,
"adilger.kernel@dilger.ca" <adilger.kernel@dilger.ca>,
"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"aswin@hp.com" <aswin@hp.com>
Subject: Re: [PATCH v4 0/3] ext4: increase mbcache scalability
Date: Tue, 11 Feb 2014 12:58:19 -0700 [thread overview]
Message-ID: <52FA80DB.2000504@hp.com> (raw)
In-Reply-To: <DBA818DD-1C87-4B98-8475-8BB8F00F7DA4@dilger.ca>
On 01/24/2014 11:09 PM, Andreas Dilger wrote:
> I think the ext4 block groups are locked with the blockgroup_lock that has about the same number of locks as the number of cores, with a max of 128, IIRC. See blockgroup_lock.h.
>
> While there is some chance of contention, it is also unlikely that all of the cores are locking this area at the same time.
>
> Cheers, Andreas
>
Andreas, looks like your assumption is correct. On all 3 systems, 80, 60 and 20 cores, I got almost identical aim7 results using either a smaller dedicated lock array or the block group lock. I'm inclined to go with using the block group lock as it does not incur any extra space.
One problem is that, with the current implementation mbcache has no knowledge of the super block, including its block group lock, of the filesystem. In my implementation I have to change the first argument of mb_cache_create() from char * to struct super_block * to be able to access the super block's block group lock. This works with my proposed change to allocate an mb_cache for each mounted ext4 filesystem. This would also require the same change, allocating an mb_cache for each mounted filesystem, to both ext2 and ext3, which would increase the scope of the patch. The other alternative, allocating a new smaller spinlock array, would not require any change to either ext2 and ext3.
I'm working on resubmitting my patches using the block group locks and extending the changes to also include both ext2 and ext3. With this approach, not only that no addition space for dedicated new spinlock array is required, the e_bdev member of struct mb_cache_entry could also be removed, reducing the space required for each mb_cache_entry.
Please let me know if you have any concern or suggestion.
Thanks,
Mak.
next prev parent reply other threads:[~2014-02-12 2:07 UTC|newest]
Thread overview: 67+ 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
2013-08-22 15:54 ` 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 [this message]
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
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
2013-09-12 12:23 ` Theodore Ts'o
2013-09-13 12:04 ` Thavatchai Makphaibulchoke
2013-09-13 18:59 ` Eric Sandeen
2013-09-17 16:43 ` Thavatchai Makphaibulchoke
2013-09-18 14:19 ` Eric Sandeen
2013-09-21 18:53 ` Theodore Ts'o
2013-09-23 15:35 ` Thavatchai Makphaibulchoke
[not found] ` <D59BF31F-934D-4DE6-9E5C-F92014F09C68@dilger.ca>
2013-09-25 18:43 ` Thavatchai Makphaibulchoke
2013-10-04 3:22 ` Andreas Dilger
2013-10-18 12:43 ` Thavatchai Makphaibulchoke
2013-10-19 23:06 ` 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
2014-01-28 12:26 [PATCH v4 0/3] ext4: increase mbcache scalability George Spelvin
2014-01-28 21:09 ` Andreas Dilger
2014-01-28 20:07 ` Thavatchai Makphaibulchoke
2014-02-11 18:47 ` Thavatchai Makphaibulchoke
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