Re: [Xen-devel] [PATCH v2 3/5] arm: set the default dom0 max_vcpus value to 1 (currently is 0)

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2012-02-23 at 18:21 +0000, Stefano Stabellini wrote:
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

Why is this needed? It makes it impossible to distinguish the "use all
CPUs" default from the "only use 1 CPU" case.

I think we want this instead, it's approx what x86 does, modulo not
using cpupool0:

8<----------------------------------------------

>From 7c66c893c5fbf485bc9071b9ef14680475b91670 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@xxxxxxxxxx>
Date: Fri, 24 Feb 2012 10:36:42 +0000
Subject: [PATCH] arm: handle dom0_max_vcpus=0 case properly

Also use xzalloc_array.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 xen/arch/arm/domain_build.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index ec5a9f3..4efe07d 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -15,13 +15,14 @@ integer_param("dom0_max_vcpus", opt_dom0_max_vcpus);
 
 struct vcpu *__init alloc_dom0_vcpu0(void)
 {
-    dom0->vcpu = xmalloc_array(struct vcpu *, opt_dom0_max_vcpus);
+    if ( opt_dom0_max_vcpus == 0 )
+        opt_dom0_max_vcpus = num_online_cpus();
+    if ( opt_dom0_max_vcpus > MAX_VIRT_CPUS )
+        opt_dom0_max_vcpus = MAX_VIRT_CPUS;
+
+    dom0->vcpu = xzalloc_array(struct vcpu *, opt_dom0_max_vcpus);
     if ( !dom0->vcpu )
-    {
-            printk("failed to alloc dom0->vccpu\n");
         return NULL;
-    }
-    memset(dom0->vcpu, 0, opt_dom0_max_vcpus * sizeof(*dom0->vcpu));
     dom0->max_vcpus = opt_dom0_max_vcpus;
 
     return alloc_vcpu(dom0, 0, 0);
-- 
1.7.2.5




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