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Re: [Xen-devel] Xen 4.0.1 "xc_map_foreign_batch: mmap failed: Cannot all

To: Jan Beulich <JBeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] Xen 4.0.1 "xc_map_foreign_batch: mmap failed: Cannot allocate memory"
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Date: Fri, 7 Jan 2011 11:18:31 +0000
Cc: Charles Arnold <CARNOLD@xxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Stefano Stabellini <Stefano.Stabellini@xxxxxxxxxxxxx>
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On Fri, 7 Jan 2011, Jan Beulich wrote:
> >>> On 06.01.11 at 21:49, Charles Arnold wrote:
> > >>> On 1/6/2011 at 10:14 AM, in message <4D25C782.5B74.0091.0@xxxxxxxxxx>, 
> > >>> Charles Arnold wrote: 
> > Attached is the messages file with the printk output.
> Hmm, a failure due to may_expand_vm() is really odd. Something
> must be explicitly setting a non-infinite RLIMIT_AS on qemu-dm (or
> one of its parents), as the default is "infinite" (as reaching "infinity"
> - being ~0UL - is simply impossible, and unduly large lengths should
> be caught by get_unmapped_area() already).
> /proc/<pid>/limits would at least tell us what the limit is.

Knowing this would be very interesting.

> And certainly qemu-dm needs to be prepared to have a
> non-infinite address space limit set on it.

Currently the number of buckets and the bucket size in the mapcache are
statically defined depending on x86_32/x86_64.
It shouldn't be difficult to make them dynamic depending on RLIMIT_AS.

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