Hi Gu,
> -----Original Message-----
> From: Gu Zheng [mailto:guz.f...@cn.fujitsu.com]
> Sent: Thursday, October 24, 2013 6:04 PM
> To: Chao Yu
> Cc: jaegeuk....@samsung.com; linux-fsde...@vger.kernel.org;
> linux-kernel@vger.kernel.org; linux-f2fs-de...@lists.sourceforge.net; '谭姝'
> Subject: Re: [f2fs-dev] [PATCH V2] f2fs: check all ones or zeros bitmap with
> bitops for better mount performance
>
> Hi Yu,
> On 10/24/2013 04:21 PM, Chao Yu wrote:
>
> > 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.
> >
> > v2:
> > use find_next_bit_le/find_next_zero_bit_le for better performance and
> readable as Jaegeuk suggested.
>
> If so, how about using find_first_{zero_}bit_le instead? It's more neat.
It seems more neat. I will take it, thanks.
>
> Regards,
> Gu
>
> >
> > Suggested-by: Jaegeuk Kim <jaegeuk....@samsung.com>
> > Signed-off-by: Tan Shu <shu....@samsung.com>
> > Signed-off-by: Yu Chao <chao2...@samsung.com>
> > ---
> > fs/f2fs/segment.h | 17 +++++++++++++++++
> > 1 file changed, 17 insertions(+)
> >
> > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index
> > 7f94d78..d25b6af 100644
> > --- a/fs/f2fs/segment.h
> > +++ b/fs/f2fs/segment.h
> > @@ -552,6 +552,23 @@ static inline void check_block_count(struct
> f2fs_sb_info *sbi,
> > /* check boundary of a given segment number */
> > BUG_ON(segno > end_segno);
> >
> > + /* check all ones or zeros valid_map */
> > + if (GET_SIT_VBLOCKS(raw_sit) == 0) {
> > + int pos = find_next_bit_le(&raw_sit->valid_map,
> > + sbi->blocks_per_seg,
> > + 0);
> > + if (pos != sbi->blocks_per_seg)
> > + BUG();
> > + return;
> > + } else if (GET_SIT_VBLOCKS(raw_sit) == sbi->blocks_per_seg) {
> > + int pos = find_next_zero_bit_le(&raw_sit->valid_map,
> > + sbi->blocks_per_seg,
> > + 0);
> > + if (pos != sbi->blocks_per_seg)
> > + BUG();
> > + return;
> > + }
> > +
> > /* check bitmap with valid block count */
> > for (i = 0; i < sbi->blocks_per_seg; i++)
> > if (f2fs_test_bit(i, raw_sit->valid_map))
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