From: Matthew Wilcox <willy@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Jan Kara <jack@suse.cz>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] writeback: Account the number of pages written back
Date: Tue, 4 Jul 2023 19:03:04 +0100 [thread overview]
Message-ID: <ZKRe2F9BVioSk8YW@casper.infradead.org> (raw)
In-Reply-To: <ZKM/jUXRjlq19AXN@dread.disaster.area>
On Tue, Jul 04, 2023 at 07:37:17AM +1000, Dave Chinner wrote:
> On Mon, Jul 03, 2023 at 03:13:15AM +0100, Matthew Wilcox wrote:
> > On Sun, Jul 02, 2023 at 01:06:15PM -0700, Andrew Morton wrote:
> > > On Wed, 28 Jun 2023 19:55:48 +0100 "Matthew Wilcox (Oracle)" <willy@infradead.org> wrote:
> > >
> > > > nr_to_write is a count of pages, so we need to decrease it by the number
> > > > of pages in the folio we just wrote, not by 1. Most callers specify
> > > > either LONG_MAX or 1, so are unaffected, but writeback_sb_inodes()
> > > > might end up writing 512x as many pages as it asked for.
> > >
> > > 512 is a big number, Should we backport this?
> >
> > I'm really not sure. Maybe? I'm hoping one of the bots comes up with a
> > meaningful performance change as a result of this patch and we find out.
>
> XFS is the only filesystem this would affect, right? AFAIA, nothing
> else enables large folios and uses writeback through
> write_cache_pages() at this point...
Good point. Still, Intel's 0day has squawked about a loss of performance
when large folios have _stopped_ being used, so they are at least testing
with XFS.
next prev parent reply other threads:[~2023-07-04 18:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-28 18:55 [PATCH] writeback: Account the number of pages written back Matthew Wilcox (Oracle)
2023-06-28 21:53 ` Dave Chinner
2023-06-29 0:01 ` Matthew Wilcox
2023-06-29 1:02 ` Dave Chinner
2023-07-02 20:06 ` Andrew Morton
2023-07-03 2:13 ` Matthew Wilcox
2023-07-03 21:37 ` Dave Chinner
2023-07-04 18:03 ` Matthew Wilcox [this message]
2023-07-06 14:21 ` Christoph Hellwig
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