linux-kernel - Re: [PATCH] fs: buffer_head, remove kmem_cache constructor to reduce memory usage under slub

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] [day] [month] [year] [list]

Date:	Tue, 09 Feb 2010 11:48:20 -0500
From:	Rik van Riel <riel@...hat.com>
To:	Richard Kennedy <richard@....demon.co.uk>
CC:	Alexander Viro <viro@...iv.linux.org.uk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	lkml <linux-kernel@...r.kernel.org>,
	Jens Axboe <jens.axboe@...cle.com>,
	Nick Piggin <npiggin@...e.de>, "Theodore Ts'o" <tytso@....edu>
Subject: Re: [PATCH]  fs: buffer_head, remove kmem_cache constructor to reduce
 memory usage under slub

On 02/09/2010 08:29 AM, Richard Kennedy wrote:
> fs: Remove the buffer_head kmem_cache constructor to reduce memory usage
> under slub.
>
> When using slub, having a kmem_cache constructor forces slub to add a
> free pointer to the size of the cached object, which can have a
> significant impact to the number of small objects that can fit into a
> slab.
>
> As buffer_head is relatively small and we can have large numbers of
> them, removing the constructor is a definite win.
>
> On x86_64 removing the constructor gives me 39 objects/slab, 3 more than
> without the patch. And on x86_32 73 objects/slab, which is 9 more.
>
> As alloc_buffer_head() already initializes each new object there is very
> little difference in actual code run.
>
> Signed-off-by: Richard Kennedy<richard@....demon.co.uk>

Reviewed-by: Rik van Riel <riel@...hat.com>

-- 
All rights reversed.
--
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/