Hi, 2013-11-18 (월), 09:37 +0800, Chao Yu: > Hi Kim, > > > -----Original Message----- > > From: Jaegeuk Kim [mailto:jaegeuk....@samsung.com] > > Sent: Monday, November 18, 2013 8:29 AM > > To: Chao Yu > > Cc: linux-fsde...@vger.kernel.org; linux-kernel@vger.kernel.org; > > linux-f2fs-de...@lists.sourceforge.net; 谭姝 > > Subject: Re: [f2fs-dev] [PATCH V2 1/2] f2fs: add a new function to support > > for merging contiguous read > > > > Hi Chao, > > > > 2013-11-16 (토), 14:14 +0800, Chao Yu: > > > For better read performance, we add a new function to support for merging > > > contiguous read as the one for write. > > > > Please consider 80 columns for the description. > > I cannot fix this at every time though. :( > > Got it, sorry about my carelessness in previous patch. > > > > > > > > > v1-->v2: > > > o add declarations here as Gu Zheng suggested. > > > > > > Signed-off-by: Chao Yu <chao2...@samsung.com> > > > Acked-by: Gu Zheng <guz.f...@cn.fujitsu.com> > > > --- > > > fs/f2fs/data.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ > > > fs/f2fs/f2fs.h | 4 ++++ > > > 2 files changed, 49 insertions(+) > > > > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > > > index aa3438c..18107cb 100644 > > > --- a/fs/f2fs/data.c > > > +++ b/fs/f2fs/data.c > > > @@ -404,6 +404,51 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct > > > page *page, > > > return 0; > > > } > > > > > > +void f2fs_submit_read_bio(struct f2fs_sb_info *sbi, int rw) > > > +{ > > > + down_read(&sbi->bio_sem); > > > > Is there any reason to use down_read()? > > Isn't that we use bio_sem to let w/r or w/w submitting be mutex?
As I examined the bio_sem, I think we don't need to use a semaphore for read and write IOs. Just it is enough to use a mutex for writes only. > > > It seems that we need to declare sbi->bio_read and sbi->bio_write > > instead of sbi->bio_sem. > > In addition to that, we need to use down_write(&sbi->bio_read) here. > > If so, it looks similar between (struct rw_semaphore) sbi->bio_read > and (struct bio *) sbi->read_bio. > How about using read_bio_sem/rbio_sem to differentiate > from sbi->read_bio? I think sbi->write_mutex and sbi->read_mutex are much better. Could you refer the following patches? Thanks, -- Jaegeuk Kim Samsung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
