From: Dave Chinner <david@fromorbit.com>
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: linux-block@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@infradead.org>,
Matthew Wilcox <willy@infradead.org>,
Ming Lei <ming.lei@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
"Darrick J . Wong" <darrick.wong@oracle.com>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
Jonathan Corbet <corbet@lwn.net>,
linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
io-uring@vger.kernel.org, linux-kernel@vger.kernel.org,
target-devel@vger.kernel.org, linux-scsi@vger.kernel.org,
linux-doc@vger.kernel.org
Subject: Re: [PATCH v1 4/6] block/psi: remove PSI annotations from direct IO
Date: Tue, 15 Dec 2020 11:56:59 +1100 [thread overview]
Message-ID: <20201215005659.GF632069@dread.disaster.area> (raw)
In-Reply-To: <1d3cf86668e44b3a3d35b5dbe759a086a157e434.1607976425.git.asml.silence@gmail.com>
On Tue, Dec 15, 2020 at 12:20:23AM +0000, Pavel Begunkov wrote:
> As reported, we must not do pressure stall information accounting for
> direct IO, because otherwise it tells that it's thrashing a page when
> actually doing IO on hot data.
>
> Apparently, bio_iov_iter_get_pages() is used only by paths doing direct
> IO, so just make it avoid setting BIO_WORKINGSET, it also saves us CPU
> cycles on doing that. For fs/direct-io.c just clear the flag before
> submit_bio(), it's not of much concern performance-wise.
>
> Reported-by: Christoph Hellwig <hch@infradead.org>
> Suggested-by: Christoph Hellwig <hch@infradead.org>
> Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> ---
> block/bio.c | 25 ++++++++++++++++---------
> fs/direct-io.c | 2 ++
> 2 files changed, 18 insertions(+), 9 deletions(-)
.....
> @@ -1099,6 +1103,9 @@ static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter)
> * fit into the bio, or are requested in @iter, whatever is smaller. If
> * MM encounters an error pinning the requested pages, it stops. Error
> * is returned only if 0 pages could be pinned.
> + *
> + * It also doesn't set BIO_WORKINGSET, so is intended for direct IO. If used
> + * otherwise the caller is responsible to do that to keep PSI happy.
> */
> int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
> {
> diff --git a/fs/direct-io.c b/fs/direct-io.c
> index d53fa92a1ab6..914a7f600ecd 100644
> --- a/fs/direct-io.c
> +++ b/fs/direct-io.c
> @@ -426,6 +426,8 @@ static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio)
> unsigned long flags;
>
> bio->bi_private = dio;
> + /* PSI is only for paging IO */
> + bio_clear_flag(bio, BIO_WORKINGSET);
Why only do this for the old direct IO path? Why isn't this
necessary for the iomap DIO path?
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2020-12-15 0:58 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-15 0:20 [PATCH v1 0/6] no-copy bvec Pavel Begunkov
2020-12-15 0:20 ` [PATCH v1 1/6] target/file: allocate the bvec array as part of struct target_core_file_cmd Pavel Begunkov
2020-12-15 0:20 ` [PATCH v1 2/6] iov_iter: optimise bvec iov_iter_advance() Pavel Begunkov
2020-12-15 9:37 ` David Laight
2020-12-15 11:23 ` Pavel Begunkov
2020-12-15 13:54 ` David Laight
2020-12-15 13:56 ` Pavel Begunkov
2020-12-22 14:03 ` Christoph Hellwig
2020-12-15 0:20 ` [PATCH v1 3/6] bio: deduplicate adding a page into bio Pavel Begunkov
2020-12-22 14:04 ` Christoph Hellwig
2020-12-15 0:20 ` [PATCH v1 4/6] block/psi: remove PSI annotations from direct IO Pavel Begunkov
2020-12-15 0:56 ` Dave Chinner [this message]
2020-12-15 1:03 ` Pavel Begunkov
2020-12-15 1:33 ` Dave Chinner
2020-12-15 11:41 ` Pavel Begunkov
2020-12-22 14:07 ` Christoph Hellwig
2020-12-15 0:20 ` [PATCH v1 5/6] bio: add a helper calculating nr segments to alloc Pavel Begunkov
2020-12-15 1:00 ` Dave Chinner
2020-12-15 1:07 ` Pavel Begunkov
2020-12-15 1:09 ` Dave Chinner
2020-12-22 14:07 ` Christoph Hellwig
2020-12-15 0:20 ` [PATCH v1 6/6] block/iomap: don't copy bvec for direct IO Pavel Begunkov
2020-12-15 1:09 ` Dave Chinner
2020-12-15 1:15 ` Pavel Begunkov
2020-12-22 14:15 ` Christoph Hellwig
2020-12-15 1:41 ` [PATCH v1 0/6] no-copy bvec Ming Lei
2020-12-15 11:14 ` Pavel Begunkov
2020-12-15 12:03 ` Ming Lei
2020-12-15 14:05 ` Pavel Begunkov
2020-12-22 14:11 ` Christoph Hellwig
2020-12-23 12:52 ` Pavel Begunkov
2020-12-23 15:51 ` Christoph Hellwig
2020-12-23 16:04 ` James Bottomley
2020-12-23 20:23 ` Douglas Gilbert
2020-12-23 20:32 ` Pavel Begunkov
2020-12-24 6:41 ` Christoph Hellwig
2020-12-24 16:45 ` Douglas Gilbert
2020-12-24 17:30 ` James Bottomley
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=20201215005659.GF632069@dread.disaster.area \
--to=david@fromorbit.com \
--cc=asml.silence@gmail.com \
--cc=axboe@kernel.dk \
--cc=corbet@lwn.net \
--cc=darrick.wong@oracle.com \
--cc=hannes@cmpxchg.org \
--cc=hch@infradead.org \
--cc=io-uring@vger.kernel.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
--cc=martin.petersen@oracle.com \
--cc=ming.lei@redhat.com \
--cc=target-devel@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
--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 NNTP newsgroup(s).