From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
Nicolas Pitre <nico@linaro.org>,
linux-xfs@vger.kernel.org, Dave Chinner <dchinner@redhat.com>,
Brian Foster <bfoster@redhat.com>,
Eric Sandeen <sandeen@sandeen.net>
Subject: Re: [PATCH] [RFC] xfs: work around unlikely() profiler glitch
Date: Wed, 25 Jan 2017 08:24:30 -0800 [thread overview]
Message-ID: <20170125162430.GN9134@birch.djwong.org> (raw)
In-Reply-To: <20170125150929.GA19906@infradead.org>
On Wed, Jan 25, 2017 at 07:09:29AM -0800, Christoph Hellwig wrote:
> On Wed, Jan 25, 2017 at 03:08:10PM +0100, Arnd Bergmann wrote:
> > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> > index d22f7930eb75..dca3ddd737d4 100644
> > --- a/fs/xfs/libxfs/xfs_bmap.c
> > +++ b/fs/xfs/libxfs/xfs_bmap.c
> > @@ -3629,7 +3629,7 @@ xfs_bmap_btalloc(
> > align = xfs_get_cowextsz_hint(ap->ip);
> > else if (xfs_alloc_is_userdata(ap->datatype))
> > align = xfs_get_extsz_hint(ap->ip);
> > - if (unlikely(align)) {
> > + if (unlikely_notrace(align)) {
> > error = xfs_bmap_extsize_align(mp, &ap->got, &ap->prev,
> > align, 0, ap->eof, 0, ap->conv,
> > &ap->offset, &ap->length);
>
> The unlikely calls on align in xfs_bmap_btalloc should simply be
> removed. They aren't actually unlikely for many workloads. I have
> a patch in my queue that I can expedite based on your report.
I was thinking exactly the same thing. Since it breaks the build
somewhere, can you send a oneliner patch so I can roll it into the rc6
fixes?
--D
> --
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prev parent reply other threads:[~2017-01-25 16:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-25 14:08 [PATCH] [RFC] xfs: work around unlikely() profiler glitch Arnd Bergmann
2017-01-25 15:09 ` Christoph Hellwig
2017-01-25 15:15 ` Arnd Bergmann
2017-01-25 16:24 ` Darrick J. Wong [this message]
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