From: Christoph Hellwig <hch@infradead.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@infradead.org>,
Pavel Begunkov <asml.silence@gmail.com>,
Matthew Wilcox <willy@infradead.org>,
Ming Lei <ming.lei@redhat.com>, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] block: add bio_iov_iter_nvecs for figuring out nr_vecs
Date: Fri, 4 Dec 2020 12:48:49 +0000 [thread overview]
Message-ID: <20201204124849.GA8768@infradead.org> (raw)
In-Reply-To: <20201203223607.GB53708@cmpxchg.org>
On Thu, Dec 03, 2020 at 05:36:07PM -0500, Johannes Weiner wrote:
> Correct, it's only interesting for pages under LRU management - page
> cache and swap pages. It should not matter for direct IO.
>
> The VM uses the page flag to tell the difference between cold faults
> (empty cache startup e.g.), and thrashing pages which are being read
> back not long after they have been reclaimed. This influences reclaim
> behavior, but can also indicate a general lack of memory.
I really wonder if we should move setting the flag out of bio_add_page
and into the writeback code, as it will do the wrong things for
non-writeback I/O, that is direct I/O or its in-kernel equivalents.
next prev parent reply other threads:[~2020-12-04 12:49 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 12:06 [PATCH] block: add bio_iov_iter_nvecs for figuring out nr_vecs Ming Lei
2020-12-01 12:52 ` Matthew Wilcox
2020-12-01 12:59 ` Christoph Hellwig
2020-12-01 13:17 ` Pavel Begunkov
2020-12-01 13:32 ` Christoph Hellwig
2020-12-01 13:36 ` Pavel Begunkov
2020-12-01 13:45 ` Christoph Hellwig
2020-12-01 13:48 ` Pavel Begunkov
2020-12-02 2:10 ` Ming Lei
2020-12-02 8:02 ` Christoph Hellwig
2020-12-03 22:36 ` Johannes Weiner
2020-12-03 23:43 ` Pavel Begunkov
2020-12-04 12:48 ` Christoph Hellwig [this message]
2020-12-10 13:18 ` Johannes Weiner
2020-12-11 13:22 ` Pavel Begunkov
2020-12-02 1:46 ` Ming Lei
2020-12-02 14:06 ` Pavel Begunkov
2020-12-02 15:02 ` Christoph Hellwig
2020-12-02 16:56 ` Jens Axboe
2020-12-07 18:07 ` Pavel Begunkov
2020-12-08 1:21 ` Ming Lei
2020-12-08 1:50 ` Ming Lei
2020-12-08 2:54 ` Pavel Begunkov
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=20201204124849.GA8768@infradead.org \
--to=hch@infradead.org \
--cc=asml.silence@gmail.com \
--cc=axboe@kernel.dk \
--cc=hannes@cmpxchg.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=ming.lei@redhat.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 NNTP newsgroup(s).