From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chao Yu Subject: Re: [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance Date: Tue, 29 Oct 2013 18:06:48 +0800 Message-ID: <002301ced48e$c615e010$5241a030$@samsung.com> References: <001f01ced473$4c5cc9c0$e5165d40$@samsung.com> <002a01ced479$925505e0$b6ff11a0$@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: 'Changman Lee' , jaegeuk.kim@samsung.com Return-path: In-reply-to: <002a01ced479$925505e0$b6ff11a0$@samsung.com> 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 Hi Lee, It's a good point. Firstly, In your patch: /* 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++; + valid_blocks += bit_count_byte(raw_sit->valid_map[i]); + BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks); } for (i = 0; i < sbi->blocks_per_seg; i++) should be replace with for (i = 0; i < SIT_VBLOCK_MAP_SIZE; i++) Secondly, I tested your patch and mine with SD and emmc with all zeros bitmap. It shows my patch takes litter time. Could you test and compare the performance of two patches. -- 1.7.10.4 > -----Original Message----- > From: Changman Lee [mailto:cm224.lee@samsung.com] > Sent: Tuesday, October 29, 2013 3:36 PM > To: 'Chao Yu'; jaegeuk.kim@samsung.com > Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; > linux-f2fs-devel@lists.sourceforge.net > Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap > with bitops for better mount performance > > Review attached patch, please. > > -----Original Message----- > From: Chao Yu [mailto:chao2.yu@samsung.com] > Sent: Tuesday, October 29, 2013 3:51 PM > To: jaegeuk.kim@samsung.com > Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; > linux-f2fs-devel@lists.sourceforge.net > Subject: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with > bitops for better mount performance > > 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. 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