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RE: [Xen-devel] [PATCH 0/6] x86: break up post-boot non-order-zero alloc

To: "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH 0/6] x86: break up post-boot non-order-zero allocations
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Date: Wed, 06 Apr 2011 07:46:29 +0100
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>>> On 06.04.11 at 04:50, Dan Magenheimer <dan.magenheimer@xxxxxxxxxx> wrote:
> IIRC, PCI-passthrough is another user of multi-page allocations.

As noted in the description, with the intended solution being to
switch from arrays to radix trees. Or do you know of other than
the mentioned cases?

> At some point, does it make sense to eliminate the multi-page
> allocation functionality, at least through the "normal"
> page allocation routines, and add a:
> /* documentation about why not to use this */
> alloc_contiguous_pages_DEPRECATED(order)
> call so that it is very explicit when future page allocation
> users "regress" by adding a multi-page allocation request?

I wouldn't go that far. Instead I was considering adding a (perhaps
one-time) warning so that things wouldn't start outright failing, but
remaining code paths get pointed out. But that ought to happen
only once all known allocations have been dealt with.


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