From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chao Yu Subject: RE: [f2fs-dev] [PATCH 3/4] f2fs: use find_next_bit_le rather than test_bit_le in, find_in_block Date: Wed, 25 Jun 2014 10:30:00 +0800 Message-ID: <002f01cf901d$78041ae0$680c50a0$@samsung.com> References: <53A950F9.907@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: 'fsdevel' , 'f2fs' To: 'Gu Zheng' , 'Jaegeuk Kim' Return-path: Received: from mailout3.samsung.com ([203.254.224.33]:38841 "EHLO mailout3.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752088AbaFYCar (ORCPT ); Tue, 24 Jun 2014 22:30:47 -0400 Received: from epcpsbgm1.samsung.com (epcpsbgm1 [203.254.230.26]) by mailout3.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0N7P005S1DN9QDC0@mailout3.samsung.com> for linux-fsdevel@vger.kernel.org; Wed, 25 Jun 2014 11:30:45 +0900 (KST) In-reply-to: <53A950F9.907@cn.fujitsu.com> Content-language: zh-cn Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Hi Gu, Just one nitpick. > -----Original Message----- > From: Gu Zheng [mailto:guz.fnst@cn.fujitsu.com] > Sent: Tuesday, June 24, 2014 6:21 PM > To: Jaegeuk Kim > Cc: fsdevel; f2fs > Subject: [f2fs-dev] [PATCH 3/4] f2fs: use find_next_bit_le rather than test_bit_le in, > find_in_block > > Use find_next_bit_le rather than test_bit_le to improve search speed > lightly. > > Signed-off-by: Gu Zheng > --- > fs/f2fs/dir.c | 43 +++++++++++++++++++++---------------------- > 1 files changed, 21 insertions(+), 22 deletions(-) > > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c > index 3edd561..ba510fb 100644 > --- a/fs/f2fs/dir.c > +++ b/fs/f2fs/dir.c > @@ -93,42 +93,41 @@ static struct f2fs_dir_entry *find_in_block(struct page *dentry_page, > const char *name, size_t namelen, int *max_slots, > f2fs_hash_t namehash, struct page **res_page) > { > - struct f2fs_dir_entry *de; > - unsigned long bit_pos = 0; > + unsigned long bit_pos = 0, bit_start = 0; > struct f2fs_dentry_block *dentry_blk = kmap(dentry_page); > const void *dentry_bits = &dentry_blk->dentry_bitmap; > - int max_len = 0; > > - while (bit_pos < NR_DENTRY_IN_BLOCK) { > - if (!test_bit_le(bit_pos, dentry_bits)) { > - if (bit_pos == 0) > - max_len = 1; > - else if (!test_bit_le(bit_pos - 1, dentry_bits)) > - max_len++; > - bit_pos++; > - continue; > + while (bit_start < NR_DENTRY_IN_BLOCK) { > + struct f2fs_dir_entry *de; > + int max_len = 0; > + > + bit_pos = find_next_bit_le(dentry_bits, > + NR_DENTRY_IN_BLOCK, bit_start); > + > + max_len = bit_pos - bit_start; > + if (max_len > *max_slots) { > + *max_slots = max_len; > + max_len = 0; It could be removed here, and also do not need to initialize above. Thanks. Yu > } > + > + if (bit_pos >= NR_DENTRY_IN_BLOCK) > + break; > + > de = &dentry_blk->dentry[bit_pos]; > if (early_match_name(name, namelen, namehash, de)) { > if (!memcmp(dentry_blk->filename[bit_pos], > name, namelen)) { > *res_page = dentry_page; > - goto found; > + return de; > } > } > - if (max_len > *max_slots) { > - *max_slots = max_len; > - max_len = 0; > - } > - bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len)); > + > + bit_start = bit_pos > + + GET_DENTRY_SLOTS(le16_to_cpu(de->name_len)); > } > > - de = NULL; > kunmap(dentry_page); > -found: > - if (max_len > *max_slots) > - *max_slots = max_len; > - return de; > + return NULL; > } > > static struct f2fs_dir_entry *find_in_level(struct inode *dir, > -- > 1.7.7 > > > ------------------------------------------------------------------------------ > Open source business process management suite built on Java and Eclipse > Turn processes into business applications with Bonita BPM Community Edition > Quickly connect people, data, and systems into organized workflows > Winner of BOSSIE, CODIE, OW2 and Gartner awards > http://p.sf.net/sfu/Bonitasoft > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel