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authorThomas Gleixner <tglx@linutronix.de>2012-05-08 14:07:48 +0200
committerThomas Gleixner <tglx@linutronix.de>2012-05-08 14:07:48 +0200
commit67ba5293f705eb1d1b98710e5ccb0f615936a6fc (patch)
treecdb4cfd94033b5c0f42eeb4de368802049880a12 /arch/x86/xen/smp.c
parent86627c93b35082f7a0e4d3111546943984b932c7 (diff)
parentd909a81b198a397593495508c4a5755fe95552fb (diff)
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Merge branch 'smp/threadalloc' into smp/hotplug
Reason: Pull in the separate branch which was created so arch/tile can base further work on it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/xen/smp.c')
-rw-r--r--arch/x86/xen/smp.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 8f44cc1a929..3700945ed0d 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -178,6 +178,7 @@ static void __init xen_fill_possible_map(void)
static void __init xen_filter_cpu_maps(void)
{
int i, rc;
+ unsigned int subtract = 0;
if (!xen_initial_domain())
return;
@@ -192,8 +193,22 @@ static void __init xen_filter_cpu_maps(void)
} else {
set_cpu_possible(i, false);
set_cpu_present(i, false);
+ subtract++;
}
}
+#ifdef CONFIG_HOTPLUG_CPU
+ /* This is akin to using 'nr_cpus' on the Linux command line.
+ * Which is OK as when we use 'dom0_max_vcpus=X' we can only
+ * have up to X, while nr_cpu_ids is greater than X. This
+ * normally is not a problem, except when CPU hotplugging
+ * is involved and then there might be more than X CPUs
+ * in the guest - which will not work as there is no
+ * hypercall to expand the max number of VCPUs an already
+ * running guest has. So cap it up to X. */
+ if (subtract)
+ nr_cpu_ids = nr_cpu_ids - subtract;
+#endif
+
}
static void __init xen_smp_prepare_boot_cpu(void)