On 11/18/2013 05:11 PM, Jaegeuk Kim wrote: > Hi, > > 2013-11-18 (월), 09:37 +0800, Chao Yu: >> Hi Kim, >> >>> -----Original Message----- >>> From: Jaegeuk Kim [mailto:jaegeuk.kim@xxxxxxxxxxx] >>> Sent: Monday, November 18, 2013 8:29 AM >>> To: Chao Yu >>> Cc: linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx; 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.yu@xxxxxxxxxxx> >>>> Acked-by: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx> >>>> --- >>>> 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. Agree. Mutex is more suitable here, we just want to protect the write bio related fields in the write patch, no relations to read. > >> >>> 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. It's more reasonable and readable. Thanks, Gu > > Could you refer the following patches? > Thanks, > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
