From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-mm@kvack.org, npiggin@kernel.dk, xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: flush vmap aliases when mapping fails
Date: Fri, 11 Mar 2011 09:49:45 +1100 [thread overview]
Message-ID: <20110310224945.GA15097@dastard> (raw)
In-Reply-To: <20110310073751.GB25374@infradead.org>
On Thu, Mar 10, 2011 at 02:37:51AM -0500, Christoph Hellwig wrote:
> On Thu, Mar 10, 2011 at 10:37:56AM +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > On 32 bit systems, vmalloc space is limited and XFS can chew through
> > it quickly as the vmalloc space is lazily freed. This can result in
> > failure to map buffers, even when there is apparently large amounts
> > of vmalloc space available. Hence, if we fail to map a buffer, purge
> > the aliases that have not yet been freed to hopefuly free up enough
> > vmalloc space to allow a retry to succeed.
>
> IMHO this should be done by vm_map_ram internally. If we can't get the
> core code fixes we can put this in as a last resort.
OK. The patch was done as part of the triage for this bug:
https://bugzilla.kernel.org/show_bug.cgi?id=27492
where the vmalloc space on 32 bit systems is getting exhausted. I
can easily move this flush-and-retry into the vmap code.
FWIW, while the VM folk might be paying attention about vmap realted
stuff, this vmap BUG() also needs triage:
https://bugzilla.kernel.org/show_bug.cgi?id=27002
And, finally, the mm-vmap-area-cache.patch in the current mmotm also
needs to be pushed forward because we've been getting reports of
excessive CPU time being spent walking the vmap area rbtree during
vm_map_ram operations and this patch supposedly fixes that
problem....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com, npiggin@kernel.dk, linux-mm@kvack.org
Subject: Re: [PATCH] xfs: flush vmap aliases when mapping fails
Date: Fri, 11 Mar 2011 09:49:45 +1100 [thread overview]
Message-ID: <20110310224945.GA15097@dastard> (raw)
In-Reply-To: <20110310073751.GB25374@infradead.org>
On Thu, Mar 10, 2011 at 02:37:51AM -0500, Christoph Hellwig wrote:
> On Thu, Mar 10, 2011 at 10:37:56AM +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > On 32 bit systems, vmalloc space is limited and XFS can chew through
> > it quickly as the vmalloc space is lazily freed. This can result in
> > failure to map buffers, even when there is apparently large amounts
> > of vmalloc space available. Hence, if we fail to map a buffer, purge
> > the aliases that have not yet been freed to hopefuly free up enough
> > vmalloc space to allow a retry to succeed.
>
> IMHO this should be done by vm_map_ram internally. If we can't get the
> core code fixes we can put this in as a last resort.
OK. The patch was done as part of the triage for this bug:
https://bugzilla.kernel.org/show_bug.cgi?id=27492
where the vmalloc space on 32 bit systems is getting exhausted. I
can easily move this flush-and-retry into the vmap code.
FWIW, while the VM folk might be paying attention about vmap realted
stuff, this vmap BUG() also needs triage:
https://bugzilla.kernel.org/show_bug.cgi?id=27002
And, finally, the mm-vmap-area-cache.patch in the current mmotm also
needs to be pushed forward because we've been getting reports of
excessive CPU time being spent walking the vmap area rbtree during
vm_map_ram operations and this patch supposedly fixes that
problem....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
--
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next prev parent reply other threads:[~2011-03-10 22:47 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-09 23:37 [PATCH] xfs: flush vmap aliases when mapping fails Dave Chinner
2011-03-10 7:37 ` Christoph Hellwig
2011-03-10 7:37 ` Christoph Hellwig
2011-03-10 22:49 ` Dave Chinner [this message]
2011-03-10 22:49 ` Dave Chinner
2011-03-17 14:24 ` Christoph Hellwig
2011-03-17 14:24 ` Christoph Hellwig
2011-03-21 12:25 ` Johannes Weiner
2011-03-21 12:25 ` Johannes Weiner
2011-03-22 12:57 ` Johannes Weiner
2011-03-22 12:57 ` Johannes Weiner
2011-03-27 23:54 ` Dave Chinner
2011-03-27 23:54 ` Dave Chinner
2011-03-18 14:24 ` Johannes Weiner
2011-03-18 14:24 ` Johannes Weiner
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