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[Xen-devel] [PATCH] x86: adjust available memory calculation for Dom0 co

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Subject: [Xen-devel] [PATCH] x86: adjust available memory calculation for Dom0 construction
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Date: Thu, 11 Mar 2010 16:44:54 +0000
Delivery-date: Thu, 11 Mar 2010 08:45:26 -0800
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With a large number of CPUs, the amount of memory needed to construct
the vCPU structures for Dom0 becomes significant and hence should be
accounted for when calculating the amount of memory to pass to Dom0.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- 2010-03-09.orig/xen/arch/x86/domain_build.c 2010-03-09 00:00:00.000000000 
+++ 2010-03-09/xen/arch/x86/domain_build.c      2010-03-10 16:49:52.000000000 
@@ -155,6 +155,13 @@ static unsigned long __init compute_dom0
     unsigned long min_pages = dom0_min_nrpages;
     unsigned long max_pages = dom0_max_nrpages;
+    avail -= (opt_dom0_max_vcpus - 1UL)
+             << get_order_from_bytes(sizeof(struct vcpu));
+#ifdef __x86_64__
+    if ( sizeof_long == sizeof(int) )
+        avail -= opt_dom0_max_vcpus - 1;
      * If domain 0 allocation isn't specified, reserve 1/16th of available
      * memory for things like DMA buffers. This reservation is clamped to 

Attachment: x86-dom0-alloc-avail.patch
Description: Text document

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