Hi Lee, > -----Original Message----- > From: Changman Lee [mailto:cm224.lee@xxxxxxxxxxx] > Sent: Wednesday, October 30, 2013 7:25 AM > To: 'Chao Yu'; jaegeuk.kim@xxxxxxxxxxx > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for > better mount performance > > > As you know, if any data or function are used once, we can use some keywords > like __initdata for data and __init for function. Thanks for reminding me that. I just think of that generating tmp data by func could save memory use or keep program size small. Regards Yu > > > -----Original Message----- > From: Chao Yu [mailto:chao2.yu@xxxxxxxxxxx] > Sent: Tuesday, October 29, 2013 7:52 PM > To: 'Changman Lee'; jaegeuk.kim@xxxxxxxxxxx > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros > bitmap with bitops for better mount performance > > Hi Lee, > > > -----Original Message----- > > From: Changman Lee [mailto:cm224.lee@xxxxxxxxxxx] > > Sent: Tuesday, October 29, 2013 3:36 PM > > To: 'Chao Yu'; jaegeuk.kim@xxxxxxxxxxx > > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > > Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or > > zeros > bitmap > > with bitops for better mount performance > > > > Review attached patch, please. > > Could we hide the pre calculated value by generating it in allocated memory > by func, because the value will be no use after build_sit_entries(); > > Regards > Yu > > > > > -----Original Message----- > > From: Chao Yu [mailto:chao2.yu@xxxxxxxxxxx] > > Sent: Tuesday, October 29, 2013 3:51 PM > > To: jaegeuk.kim@xxxxxxxxxxx > > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > > 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 <jaegeuk.kim@xxxxxxxxxxx> > > Signed-off-by: Shu Tan <shu.tan@xxxxxxxxxxx> > > Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx> > > --- > > 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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