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authorRusty Russell <rusty@rustcorp.com.au>2008-12-08 20:28:04 +1030
committerAvi Kivity <avi@redhat.com>2008-12-31 16:55:45 +0200
commit6ef7a1bc45f80fe0a263119d404688c596ea5031 (patch)
tree331e8f5ba73b53fa5997eb4dc376249d18897876 /virt
parent498468961ed6f62a306eb90c49125776c526fa40 (diff)
downloadlinux-linaro-stable-6ef7a1bc45f80fe0a263119d404688c596ea5031.tar.gz
KVM: use modern cpumask primitives, no cpumask_t on stack
We're getting rid on on-stack cpumasks for large NR_CPUS. 1) Use cpumask_var_t/alloc_cpumask_var. 2) smp_call_function_mask -> smp_call_function_many 3) cpus_clear, cpus_empty, cpu_set -> cpumask_clear, cpumask_empty, cpumask_set_cpu. This actually generates slightly smaller code than the old one with CONFIG_CPUMASKS_OFFSTACK=n. (gcc knows that cpus cannot be NULL in that case, where cpumask_var_t is cpumask_t[1]). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c23
1 files changed, 14 insertions, 9 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ba4275d06fb7..2d6ca7968d65 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -555,12 +555,14 @@ static void ack_flush(void *_completed)
static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
{
int i, cpu, me;
- cpumask_t cpus;
- bool called = false;
+ cpumask_var_t cpus;
+ bool called = true;
struct kvm_vcpu *vcpu;
+ if (alloc_cpumask_var(&cpus, GFP_ATOMIC))
+ cpumask_clear(cpus);
+
me = get_cpu();
- cpus_clear(cpus);
for (i = 0; i < KVM_MAX_VCPUS; ++i) {
vcpu = kvm->vcpus[i];
if (!vcpu)
@@ -568,14 +570,17 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
if (test_and_set_bit(req, &vcpu->requests))
continue;
cpu = vcpu->cpu;
- if (cpu != -1 && cpu != me)
- cpu_set(cpu, cpus);
- }
- if (!cpus_empty(cpus)) {
- smp_call_function_mask(cpus, ack_flush, NULL, 1);
- called = true;
+ if (cpus != NULL && cpu != -1 && cpu != me)
+ cpumask_set_cpu(cpu, cpus);
}
+ if (unlikely(cpus == NULL))
+ smp_call_function_many(cpu_online_mask, ack_flush, NULL, 1);
+ else if (!cpumask_empty(cpus))
+ smp_call_function_many(cpus, ack_flush, NULL, 1);
+ else
+ called = false;
put_cpu();
+ free_cpumask_var(cpus);
return called;
}