From: Jan Kara <jack@suse.cz>
To: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-fsdevel@vger.kernel.org,
Matthew Wilcox <willy@infradead.org>,
"Darrick J . Wong" <djwong@kernel.org>,
Ojaswin Mujoo <ojaswin@linux.ibm.com>, Jan Kara <jack@suse.cz>
Subject: Re: [PATCHv2 2/2] iomap: Optimize iomap_read_folio
Date: Thu, 9 May 2024 12:40:52 +0200 [thread overview]
Message-ID: <20240509104052.mixeiy7ihxlzzbba@quack3> (raw)
In-Reply-To: <92ae9f3333c9a7e66214568d08f45664261c899c.1715067055.git.ritesh.list@gmail.com>
On Tue 07-05-24 14:25:43, Ritesh Harjani (IBM) wrote:
> iomap_readpage_iter() handles "uptodate blocks" and "not uptodate blocks"
> within a folio separately. This makes iomap_read_folio() to call into
> ->iomap_begin() to request for extent mapping even though it might already
> have an extent which is not fully processed.
> This happens when we either have a large folio or with bs < ps. In these
> cases we can have sub blocks which can be uptodate (say for e.g. due to
> previous writes). With iomap_read_folio_iter(), this is handled more
> efficiently by not calling ->iomap_begin() call until all the sub blocks
> with the current folio are processed.
>
> iomap_read_folio_iter() handles multiple sub blocks within a given
> folio but it's implementation logic is similar to how
> iomap_readahead_iter() handles multiple folios within a single mapped
> extent. Both of them iterate over a given range of folio/mapped extent
> and call iomap_readpage_iter() for reading.
>
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
> cc: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
> ---
> fs/iomap/buffered-io.c | 20 +++++++++++++++++++-
> 1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 9f79c82d1f73..a9bd74ee7870 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -444,6 +444,24 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
> return pos - orig_pos + plen;
> }
>
> +static loff_t iomap_read_folio_iter(const struct iomap_iter *iter,
> + struct iomap_readpage_ctx *ctx)
> +{
> + struct folio *folio = ctx->cur_folio;
> + size_t offset = offset_in_folio(folio, iter->pos);
> + loff_t length = min_t(loff_t, folio_size(folio) - offset,
> + iomap_length(iter));
> + loff_t done, ret;
> +
> + for (done = 0; done < length; done += ret) {
> + ret = iomap_readpage_iter(iter, ctx, done);
> + if (ret <= 0)
> + return ret;
> + }
> +
> + return done;
> +}
> +
> int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops)
> {
> struct iomap_iter iter = {
> @@ -459,7 +477,7 @@ int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops)
> trace_iomap_readpage(iter.inode, 1);
>
> while ((ret = iomap_iter(&iter, ops)) > 0)
> - iter.processed = iomap_readpage_iter(&iter, &ctx, 0);
> + iter.processed = iomap_read_folio_iter(&iter, &ctx);
>
> if (ret < 0)
> folio_set_error(folio);
> --
> 2.44.0
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
prev parent reply other threads:[~2024-05-09 10:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-07 8:55 [PATCHv2 0/2] iomap: Optimize read_folio Ritesh Harjani (IBM)
2024-05-07 8:55 ` [PATCHv2 1/2] iomap: Fix iomap_adjust_read_range for plen calculation Ritesh Harjani (IBM)
2024-05-09 10:33 ` Jan Kara
2024-05-07 8:55 ` [PATCHv2 2/2] iomap: Optimize iomap_read_folio Ritesh Harjani (IBM)
2024-05-07 21:11 ` Darrick J. Wong
2024-05-09 4:55 ` Christoph Hellwig
2024-05-09 10:40 ` Jan Kara [this message]
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=20240509104052.mixeiy7ihxlzzbba@quack3 \
--to=jack@suse.cz \
--cc=djwong@kernel.org \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
--cc=ojaswin@linux.ibm.com \
--cc=ritesh.list@gmail.com \
--cc=willy@infradead.org \
/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 read-only IMAP folder(s) and NNTP newsgroup(s).