From: Christoph Hellwig <hch@lst.de>
To: Dave Chinner <david@fromorbit.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>,
Christoph Hellwig <hch@lst.de>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Andreas Gruenbacher <agruenba@redhat.com>,
linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 07/12] xfs: don't preallocate a transaction for file size updates
Date: Tue, 25 Jun 2019 12:25:07 +0200 [thread overview]
Message-ID: <20190625102507.GA1986@lst.de> (raw)
In-Reply-To: <20190624231523.GC7777@dread.disaster.area>
On Tue, Jun 25, 2019 at 09:15:23AM +1000, Dave Chinner wrote:
> > So, uh, how much of a hit do we take for having to allocate a
> > transaction for a file size extension? Particularly since we can
> > combine those things now?
>
> Unless we are out of log space, the transaction allocation and free
> should be largely uncontended and so it's just a small amount of CPU
> usage. i.e it's a slab allocation/free and then lockless space
> reservation/free. If we are out of log space, then we sleep waiting
> for space - the issue really comes down to where it is better to
> sleep in that case....
I see the general point, but we'll still have the same issue with
unwritten extent conversion and cow completions, and I don't remember
seeing any issue in that regard. And we'd hit exactly that case
with random writes to preallocated or COW files, i.e. the typical image
file workload.
next prev parent reply other threads:[~2019-06-25 10:25 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 5:52 lift the xfs writepage code into iomap Christoph Hellwig
2019-06-24 5:52 ` [PATCH 01/12] list.h: add a list_pop helper Christoph Hellwig
2019-06-24 14:53 ` Darrick J. Wong
2019-06-24 15:51 ` Matthew Wilcox
2019-06-25 10:06 ` Christoph Hellwig
2019-06-24 5:52 ` [PATCH 02/12] xfs: simplify xfs_chain_bio Christoph Hellwig
2019-06-24 15:14 ` Darrick J. Wong
2019-06-24 5:52 ` [PATCH 03/12] xfs: fix a comment typo in xfs_submit_ioend Christoph Hellwig
2019-06-24 14:53 ` Darrick J. Wong
2019-06-24 5:52 ` [PATCH 04/12] xfs: initialize ioma->flags in xfs_bmbt_to_iomap Christoph Hellwig
2019-06-24 14:57 ` Darrick J. Wong
2019-06-25 10:07 ` Christoph Hellwig
2019-06-25 15:13 ` Darrick J. Wong
2019-06-25 15:21 ` Christoph Hellwig
2019-06-24 5:52 ` [PATCH 05/12] xfs: use a struct iomap in xfs_writepage_ctx Christoph Hellwig
2019-06-24 15:50 ` Darrick J. Wong
2019-06-24 5:52 ` [PATCH 06/12] xfs: remove XFS_TRANS_NOFS Christoph Hellwig
2019-06-24 15:58 ` Darrick J. Wong
2019-06-24 22:59 ` Dave Chinner
2019-06-25 10:12 ` Christoph Hellwig
2019-06-24 5:52 ` [PATCH 07/12] xfs: don't preallocate a transaction for file size updates Christoph Hellwig
2019-06-24 16:17 ` Darrick J. Wong
2019-06-24 23:15 ` Dave Chinner
2019-06-25 10:25 ` Christoph Hellwig [this message]
2019-06-27 22:23 ` Dave Chinner
2019-06-24 5:52 ` [PATCH 08/12] xfs: simplify xfs_ioend_can_merge Christoph Hellwig
2019-06-24 16:00 ` Darrick J. Wong
2019-06-24 5:52 ` [PATCH 09/12] xfs: refactor the ioend merging code Christoph Hellwig
2019-06-24 16:04 ` Darrick J. Wong
2019-06-24 16:06 ` Nikolay Borisov
2019-06-25 10:14 ` Christoph Hellwig
2019-06-25 12:42 ` Nikolay Borisov
2019-06-25 14:45 ` Darrick J. Wong
2019-06-24 5:52 ` [PATCH 10/12] xfs: remove the fork fields in the writepage_ctx and ioend Christoph Hellwig
2019-06-24 16:08 ` Darrick J. Wong
2019-06-24 5:52 ` [PATCH 11/12] iomap: move the xfs writeback code to iomap.c Christoph Hellwig
2019-06-24 15:46 ` Darrick J. Wong
2019-06-25 10:08 ` Christoph Hellwig
2019-06-24 23:43 ` Dave Chinner
2019-06-25 10:10 ` Christoph Hellwig
2019-06-28 0:45 ` Dave Chinner
2019-06-28 5:33 ` Christoph Hellwig
2019-07-01 0:08 ` Dave Chinner
2019-07-01 6:43 ` Christoph Hellwig
2019-07-01 23:09 ` Dave Chinner
2019-06-28 22:27 ` Luis Chamberlain
2019-07-11 21:31 ` Brendan Higgins
2019-06-24 5:52 ` [PATCH 12/12] iomap: add tracing for the address space operations Christoph Hellwig
2019-06-24 23:49 ` Dave Chinner
2019-06-25 10:15 ` Christoph Hellwig
2019-06-25 14:47 ` Darrick J. Wong
2019-06-27 22:35 ` 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=20190625102507.GA1986@lst.de \
--to=hch@lst.de \
--cc=Damien.LeMoal@wdc.com \
--cc=agruenba@redhat.com \
--cc=darrick.wong@oracle.com \
--cc=david@fromorbit.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-xfs@vger.kernel.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).