From: zhangxiao <xiao.zhang@windriver.com>
To: NeilBrown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org,
dm-devel@redhat.com
Subject: Re: The DM_BUFIO_HASH_BITS is defined as 20, any plan to make it flexible?
Date: Tue, 2 Dec 2014 16:40:37 +0800 [thread overview]
Message-ID: <547D7B05.50406@windriver.com> (raw)
In-Reply-To: <20141202193618.6d3adb22@notabene.brown>
On 2014年12月02日 16:36, NeilBrown wrote:
> On Tue, 2 Dec 2014 16:32:14 +0800 zhangxiao <xiao.zhang@windriver.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:
>
Thank you for your kindly remind. :-)
Regards
Xiao
> DEVICE-MAPPER (LVM)
> M: Alasdair Kergon <agk@redhat.com>
> M: Mike Snitzer <snitzer@redhat.com>
> M: dm-devel@redhat.com
> L: dm-devel@redhat.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
>
next prev parent reply other threads:[~2014-12-02 8:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-02 8:32 The DM_BUFIO_HASH_BITS is defined as 20, any plan to make it flexible? zhangxiao
2014-12-02 8:36 ` NeilBrown
2014-12-02 8:40 ` zhangxiao [this message]
-- strict thread matches above, loose matches on Subject: below --
2014-12-02 8:43 zhangxiao
2014-12-02 14:00 ` Mike Snitzer
2014-12-03 14:19 ` [dm-devel] " Joe Thornber
2014-12-03 16:17 ` Mike Snitzer
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