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

From: zhangxiao
Date: Tue Dec 02 2014 - 03:40:52 EST

On 2014å12æ02æ 16:36, NeilBrown wrote:
On Tue, 2 Dec 2014 16:32:14 +0800 zhangxiao <xiao.zhang@xxxxxxxxxxxxx> 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. :-)


M: Alasdair Kergon <agk@xxxxxxxxxx>
M: Mike Snitzer <snitzer@xxxxxxxxxx>
M: dm-devel@xxxxxxxxxx
L: dm-devel@xxxxxxxxxx
T: git git://
T: quilt
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


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