From: Al Viro <viro@zeniv.linux.org.uk>
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
Jens Axboe <axboe@kernel.dk>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC] mm: optimise generic_file_read_iter
Date: Fri, 6 Aug 2021 13:48:38 +0000 [thread overview]
Message-ID: <YQ09tqMda2ke2qHy@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <07bd408d6cad95166b776911823b40044160b434.1628248975.git.asml.silence@gmail.com>
On Fri, Aug 06, 2021 at 12:42:43PM +0100, Pavel Begunkov wrote:
> Unless direct I/O path of generic_file_read_iter() ended up with an
> error or a short read, it doesn't use inode. So, load inode and size
> later, only when they're needed. This cuts two memory reads and also
> imrpoves code generation, e.g. loads from stack.
... and the same question here.
> NOTE: as a side effect, it reads inode->i_size after ->direct_IO(), and
> I'm not sure whether that's valid, so would be great to get feedback
> from someone who knows better.
Ought to be safe, I think, but again, how much effect have you observed
from the patch?
next prev parent reply other threads:[~2021-08-06 13:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-06 11:42 [RFC] mm: optimise generic_file_read_iter Pavel Begunkov
2021-08-06 13:48 ` Al Viro [this message]
2021-08-06 17:18 ` Jens Axboe
2021-08-07 10:30 ` Pavel Begunkov
2021-08-06 23:49 ` Dave Chinner
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=YQ09tqMda2ke2qHy@zeniv-ca.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=akpm@linux-foundation.org \
--cc=asml.silence@gmail.com \
--cc=axboe@kernel.dk \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.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).