From: Jaegeuk Kim <jaegeuk@kernel.org>
To: heyunlei <heyunlei@huawei.com>
Cc: linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [PATCH] f2fs: add a modify discard command function
Date: Wed, 1 Mar 2017 11:48:44 -0800 [thread overview]
Message-ID: <20170301194844.GD18600@jaegeuk.local> (raw)
In-Reply-To: <6b67a9d1-645f-9dea-6fda-9324f7ac0cac@huawei.com>
On 02/28, heyunlei wrote:
> Hi Jaegeuk,
>
> On 2017/2/28 7:08, Jaegeuk Kim wrote:
> > On 02/27, Yunlei He wrote:
> > > This patch add a function to modify discard command if one segment
> > > reuse before discard. Split this segment from multi-segments discard
> > > range, and discard the left bigger range.
> >
> > Now MAX_DISCARD_BLOCKS() is set to section size, so there will be no
> > multi-sections discard range. Am I missing some cases?
>
> I think MAX_DISCARD_BLOCKS() just limit small discard and fstrim, f2fs
>
> can still send multi-segments discard range if prefree segments is continuous.
Got it.
Comments below.
> > > Signed-off-by: Yunlei He <heyunlei@huawei.com>
> > > ---
> > > fs/f2fs/segment.c | 18 +++++++++++++++++-
> > > 1 file changed, 17 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > index 9006d8e..5af736b 100644
> > > --- a/fs/f2fs/segment.c
> > > +++ b/fs/f2fs/segment.c
> > > @@ -672,6 +672,22 @@ static void __remove_discard_cmd(struct f2fs_sb_info *sbi, struct discard_cmd *d
> > > kmem_cache_free(discard_cmd_slab, dc);
> > > }
> > >
> > > +static void __modify_discard_cmd(struct f2fs_sb_info *sbi, struct discard_cmd *dc, block_t blkaddr)
How about modifying the name "modify" to "punch"?
> > > +{
> > > + block_t end_block = START_BLOCK(sbi, GET_SEGNO(sbi, blkaddr) + 1);
> > > +
> > > + if (dc->lstart + dc->len <= end_block) {
> > > + __remove_discard_cmd(sbi, dc);
> > > + return;
> > > + }
> > > +
> > > + if (dc->lstart - blkaddr < dc->lstart + dc->len - end_block) {
The blkaddr is larger than or equal to dc->lstart all the time, resulting in
overflow?
Thanks,
> > > + dc->lstart = end_block;
> > > + dc->len -= (end_block - dc->lstart);
> > > + } else
> > > + dc->len = blkaddr - dc->lstart;
> > > +}
> > > +
> > > /* This should be covered by global mutex, &sit_i->sentry_lock */
> > > void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
> > > {
> > > @@ -699,7 +715,7 @@ void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
> > > if (dc->state == D_SUBMIT)
> > > wait_for_completion_io(&dc->wait);
> > > else
> > > - __remove_discard_cmd(sbi, dc);
> > > + __modify_discard_cmd(sbi, dc, blkaddr);
> > > }
> > > }
> > > blk_finish_plug(&plug);
> > > --
> > > 2.10.1
> >
> > .
> >
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, SlashDot.org! http://sdm.link/slashdot
next prev parent reply other threads:[~2017-03-01 19:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-27 7:19 [PATCH] f2fs: add a modify discard command function Yunlei He
2017-02-27 23:08 ` Jaegeuk Kim
2017-02-28 1:51 ` heyunlei
2017-03-01 19:48 ` Jaegeuk Kim [this message]
2017-03-02 2:07 ` heyunlei
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170301194844.GD18600@jaegeuk.local \
--to=jaegeuk@kernel.org \
--cc=heyunlei@huawei.com \
--cc=linux-f2fs-devel@lists.sourceforge.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).