[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-id: <000301ceef3c$ecee00a0$c6ca01e0$@samsung.com>
Date: Mon, 02 Dec 2013 16:59:28 +0800
From: Chao Yu <chao2.yu@...sung.com>
To: jaegeuk.kim@...sung.com
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net,
'谭姝' <shu.tan@...sung.com>
Subject: RE: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
Hi Kim,
> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk.kim@...sung.com]
> Sent: Monday, December 02, 2013 4:15 PM
> To: Chao Yu
> Cc: linux-fsdevel@...r.kernel.org; linux-kernel@...r.kernel.org; linux-f2fs-devel@...ts.sourceforge.net; 谭姝
> Subject: RE: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
>
> 2013-12-02 (월), 14:14 +0800, Chao Yu:
> > Hi Kim,
> >
> > > -----Original Message-----
> > > From: Jaegeuk Kim [mailto:jaegeuk.kim@...sung.com]
> > > Sent: Saturday, November 30, 2013 9:48 AM
> > > Cc: linux-fsdevel@...r.kernel.org; linux-kernel@...r.kernel.org; linux-f2fs-devel@...ts.sourceforge.net
> > > Subject: [f2fs-dev] [PATCH] f2fs: remove the own bi_private allocation
> > >
> > > Previously f2fs allocates its own bi_private data structure all the time even
> > > though we don't use it. But, can we remove this bi_private allocation?
> > >
> > > This patch removes such the additional bi_private allocation.
> > >
> > > 1. Retrieve f2fs_sb_info from its page->mapping->host->i_sb.
> > > - This removes the usecases of bi_private in end_io.
> > >
> > > 2. Use bi_private only when we really need it.
> > > - The bi_private is used only when the checkpoint procedure is conducted.
> > > - When conducting the checkpoint, f2fs submits a META_FLUSH bio to wait its bio
> > > completion.
> > > - Since we have no dependancies to remove bi_private now, let's just use
> > > bi_private pointer as the completion pointer.
> > >
> > > Signed-off-by: Jaegeuk Kim <jaegeuk.kim@...sung.com>
> > > ---
> > > fs/f2fs/segment.c | 43 ++++++++++++++++---------------------------
> > > fs/f2fs/segment.h | 7 -------
> > > 2 files changed, 16 insertions(+), 34 deletions(-)
> > >
> > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > index 0387863..0db4027 100644
> > > --- a/fs/f2fs/segment.c
> > > +++ b/fs/f2fs/segment.c
> > > @@ -791,7 +791,7 @@ static void f2fs_end_io_write(struct bio *bio, int err)
> > > {
> > > const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
> > > struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
> > > - struct bio_private *p = bio->bi_private;
f2fs_bug_on(unlikely(!bvec->bv_page->mapping));
> > > + struct f2fs_sb_info *sbi = F2FS_SB(bvec->bv_page->mapping->host->i_sb);
> >
> > I'm not sure whether bvec->bv_page->mapping will be set to NULL in the flow
> > where may not check WRITEBACK flag of page. Is it possible?
>
> The mapping should be not NULL cause it is a writebacking page.
> Otherwise, it's a bug.
If so, should we add additional code as above?
Regards,
Yu
> Thanks,
>
> --
> Jaegeuk Kim
> Samsung
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists