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

[NeilBrown]

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:

DEVICE-MAPPER  (LVM)
M:	Alasdair Kergon <agk@xxxxxxxxxx>
M:	Mike Snitzer <snitzer@xxxxxxxxxx>
M:	dm-devel@xxxxxxxxxx
L:	dm-devel@xxxxxxxxxx
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

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