From mboxrd@z Thu Jan 1 00:00:00 1970 From: zhangxiao 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 Message-ID: <547D7B05.50406@windriver.com> References: <547D790E.3070803@windriver.com> <20141202193618.6d3adb22@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20141202193618.6d3adb22@notabene.brown> Sender: linux-kernel-owner@vger.kernel.org To: NeilBrown Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com List-Id: linux-raid.ids On 2014=E5=B9=B412=E6=9C=8802=E6=97=A5 16:36, NeilBrown wrote: > On Tue, 2 Dec 2014 16:32:14 +0800 zhangxiao 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 > M: Mike Snitzer > 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/li= nux-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 >