linux-kernel - Re: The DM_BUFIO_HASH_BITS is defined as 20, any plan to make it flexible?

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]

Message-ID: <20141202193618.6d3adb22@notabene.brown>
Date:	Tue, 2 Dec 2014 19:36:18 +1100
From:	NeilBrown <neilb@...e.de>
To:	zhangxiao <xiao.zhang@...driver.com>
Cc:	<linux-raid@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	dm-devel@...hat.com
Subject: Re: The DM_BUFIO_HASH_BITS is defined as 20, any plan to make it
 flexible?

On Tue, 2 Dec 2014 16:32:14 +0800 zhangxiao <xiao.zhang@...driver.com> wrote:

> Hi NeilBrown,
> 
> See drivers/md/dm-bufio.c as below:
>    50 /*
>    51  * Buffer hash
>    52  */
>    53 #define DM_BUFIO_HASH_BITS      20
>    54 #define DM_BUFIO_HASH(block) \
>    55         ((((block) >> DM_BUFIO_HASH_BITS) ^ (block)) & \
>    56          ((1 << DM_BUFIO_HASH_BITS) - 1))
> "drivers/md/dm-bufio.c" 1854L, 45375C 
> 
> 
> DM_BUFIO_HASH_BITS was defined as 20 and it maybe not fit for some
> use case with limited resources. Do we have any plan to make it more
> flexible? Like module parameter or something else?
> 

Thanks, but this question should be address to:

DEVICE-MAPPER  (LVM)
M:	Alasdair Kergon <agk@...hat.com>
M:	Mike Snitzer <snitzer@...hat.com>
M:	dm-devel@...hat.com
L:	dm-devel@...hat.com
W:	http://sources.redhat.com/dm
Q:	http://patchwork.kernel.org/project/dm-devel/list/
T:	git git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git
T:	quilt http://people.redhat.com/agk/patches/linux/editing/
S:	Maintained
F:	Documentation/device-mapper/
F:	drivers/md/dm*
F:	drivers/md/persistent-data/
F:	include/linux/device-mapper.h
F:	include/linux/dm-*.h
F:	include/uapi/linux/dm-*.h

NeilBrown

Content of type "application/pgp-signature" skipped