This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] numa=on broken

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] numa=on broken
From: Ryan Harper <ryanh@xxxxxxxxxx>
Date: Fri, 30 Mar 2007 13:08:53 -0500
Cc: Ryan Harper <ryanh@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Fri, 30 Mar 2007 19:10:27 +0100
Envelope-to: Keir.Fraser@xxxxxxxxxxxx
In-reply-to: <C2330CAA.52DF%Keir.Fraser@xxxxxxxxxxxx>
References: <20070330173432.GR28736@xxxxxxxxxx> <C2330CAA.52DF%Keir.Fraser@xxxxxxxxxxxx>
User-agent: Mutt/1.5.6+20040907i
* Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> [2007-03-30 13:06]:
> On 30/3/07 18:34, "Ryan Harper" <ryanh@xxxxxxxxxx> wrote:
> > Looking a little deeper, it looks like in end_boot_allocator() we are
> > attempting to dynamically allocate memory for addition arrays in avail[]
> > and for the heap.  This uses xmalloc() which relies on
> > alloc_xenheap_pages() to work.  alloc_xenheap_pages() can't function
> > until end_boot_allocator() completes.  Prior to end_boot_alloctor(), one
> > needs to use alloc_boot_pages().
> > 
> > Any thoughts on how to proceed here?
> Since the buddy allocators are initialised with memory from address zero
> upwards, I would expect everything to work fine if numa node zero always
> owns the first block of physical memory. This is because we statically
> allocate space for heap metadata for numa node zero (since even non-numa
> machines have a 'numa node zero'), so by the time you need to allocate
> memory for other numa nodes you're xenheap will be populated with memory.
> So -- can we ensure that the node that owns low memory is node zero?

AFAIK, that is the case, look at the SRAT table:

(XEN) SRAT: Node 0 PXM 0 0-a0000
(XEN) SRAT: Node 0 PXM 0 0-e0000000
(XEN) SRAT: Node 1 PXM 1 100000000-200000000

Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
(512) 838-9253   T/L: 678-9253