From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chao Yu Subject: [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance Date: Tue, 29 Oct 2013 14:50:40 +0800 Message-ID: <001f01ced473$4c5cc9c0$e5165d40$@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net To: jaegeuk.kim@samsung.com Return-path: Content-language: zh-cn List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net List-Id: linux-fsdevel.vger.kernel.org Previously, check_block_count check valid_map with bit data type in common scenario that sit has all ones or zeros bitmap, it makes low mount performance. So let's check the special bitmap with integer data type instead of the bit one. v1-->v2: use find_next_{zero_}bit_le for better performance and readable as Jaegeuk suggested. use neat logogram in comment as Gu Zheng suggested. search continuous ones or zeros for better performance when checking mixed bitmap. Suggested-by: Jaegeuk Kim Signed-off-by: Shu Tan Signed-off-by: Chao Yu --- fs/f2fs/segment.h | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index abe7094..a7abfa8 100644 --- a/fs/f2fs/segment.h +++ b/fs/f2fs/segment.h @@ -550,8 +550,9 @@ static inline void check_block_count(struct f2fs_sb_info *sbi, { struct f2fs_sm_info *sm_info = SM_I(sbi); unsigned int end_segno = sm_info->segment_count - 1; + bool is_valid = test_bit_le(0, raw_sit->valid_map) ? true : false; int valid_blocks = 0; - int i; + int cur_pos = 0, next_pos; /* check segment usage */ BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg); @@ -560,9 +561,19 @@ static inline void check_block_count(struct f2fs_sb_info *sbi, BUG_ON(segno > end_segno); /* check bitmap with valid block count */ - for (i = 0; i < sbi->blocks_per_seg; i++) - if (f2fs_test_bit(i, raw_sit->valid_map)) - valid_blocks++; + do { + if (is_valid) { + next_pos = find_next_zero_bit_le(&raw_sit->valid_map, + sbi->blocks_per_seg, + cur_pos); + valid_blocks += next_pos - cur_pos; + } else + next_pos = find_next_bit_le(&raw_sit->valid_map, + sbi->blocks_per_seg, + cur_pos); + cur_pos = next_pos; + is_valid = !is_valid; + } while (cur_pos < sbi->blocks_per_seg); BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks); } -- 1.7.9.5 ------------------------------------------------------------------------------ Android is increasing in popularity, but the open development platform that developers love is also attractive to malware creators. Download this white paper to learn more about secure code signing practices that can help keep Android apps secure. http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktrk