Re: [PATCH 1/4] hvm: NUMA guest: extend memops hypercall

[Andre Przywara <andre.przywara@amd.com>]

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Keir Fraser wrote:
> On 4/7/08 16:28, "Andre Przywara" <andre.przywara@amd.com> wrote:
> 
>> Have you applied the patches correctly? From 02_numa_guest.patch:
>> @@ -115,7 +113,7 @@
>>               goto out;
>>
>>           page = alloc_domheap_pages(
>> -            d, a->extent_order, a->memflags | MEMF_node(node));
>> +            d, a->extent_order, a->memflags);
>>           if ( unlikely(page == NULL) )
>>           {
>>               gdprintk(XENLOG_INFO, "Could not allocate order=%d extent:"
>>
>> The other use of MEMF_node is in exchange_memory, which is not given any
>> NUMA node info from the caller, so this is correct.
> 
> When sent a patch sequence I expect the patches to apply and work
> independently (when applied one-by-one in order).
IMHO that is what they do (beside the below issue patch 1 and 2 are more 
or less refactoring without functional changes), but anyway...

> Anyway, your second patch changes the default NUMA allocation policy from
> allocate on home node for the domain to allocate on node I'm currently
> executing on. That would seem a net loss for PV guests (whose builder will
> not be explicitly specifying the numa node for allocations).
Right you are, I have missed the subtle difference between both (the 
code isn't as clear as your sentence). The below patch should fix this 
(by catching NUMA_NO_NODE while still knowing struct domain*).
If there are no further issues, I will resend the patches.

Regards,
Andre.

-- 
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 277-84917
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diff -r a3d712538f1b xen/common/page_alloc.c
--- a/xen/common/page_alloc.c	Fri Jul 04 15:57:01 2008 +0200
+++ b/xen/common/page_alloc.c	Sat Jul 05 01:09:48 2008 +0200
@@ -792,6 +792,8 @@ struct page_info *alloc_domheap_pages(
 
     ASSERT(!in_irq());
 
+    if ( node == NUMA_NO_NODE ) node = domain_to_node (d);
+
     bits = domain_clamp_alloc_bitsize(d, bits ? : (BITS_PER_LONG+PAGE_SHIFT));
     if ( bits <= (PAGE_SHIFT + 1) )
         return NULL;

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