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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.