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From: Johannes Weiner <hannes@cmpxchg.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>,
	xfs@oss.sgi.com, npiggin@kernel.dk, linux-mm@kvack.org
Subject: Re: [PATCH] xfs: flush vmap aliases when mapping fails
Date: Fri, 18 Mar 2011 15:24:14 +0100	[thread overview]
Message-ID: <20110318142414.GV2140@cmpxchg.org> (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.

Agreed, this should be fixed in the vmalloc-ator.

It is already supposed to purge the lazy-freed mappings before it
fails an allocation, I am trying to figure out what's going on.

Your proposed workaround looks fine to me until vmalloc is fixed.

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      parent reply	other threads:[~2011-03-18 14:24 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1299713876-7747-1-git-send-email-david@fromorbit.com>
2011-03-10  7:37 ` Christoph Hellwig
2011-03-10 22:49   ` Dave Chinner
2011-03-17 14:24     ` Christoph Hellwig
2011-03-21 12:25     ` Johannes Weiner
2011-03-22 12:57       ` Johannes Weiner
2011-03-27 23:54         ` Dave Chinner
2011-03-18 14:24   ` Johannes Weiner [this message]

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