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| author | Rusty Russell <rusty@rustcorp.com.au> | 2008-12-08 20:28:04 +1030 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2008-12-31 16:55:45 +0200 |
| commit | 6ef7a1bc45f80fe0a263119d404688c596ea5031 (patch) | |
| tree | 331e8f5ba73b53fa5997eb4dc376249d18897876 /virt | |
| parent | 498468961ed6f62a306eb90c49125776c526fa40 (diff) | |
| download | linux-stable-6ef7a1bc45f80fe0a263119d404688c596ea5031.tar.gz linux-stable-6ef7a1bc45f80fe0a263119d404688c596ea5031.tar.bz2 linux-stable-6ef7a1bc45f80fe0a263119d404688c596ea5031.zip | |
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.c | 23 |
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; } |