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| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2021-09-03 10:51:40 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-04-05 12:23:30 +0300 |
| commit | 7958663668ef0ffe49c294ee55c83770b532c685 (patch) | |
| tree | 61d9ee35cd45cd96381d80be0c46b77ebc5991a2 /virt/kvm/kvm_main.c | |
| parent | 6100066358ee1bc5f2d329a7d8eb32bf8e3ee74d (diff) | |
| download | linux-7958663668ef0ffe49c294ee55c83770b532c685.tar.xz | |
KVM: Pre-allocate cpumasks for kvm_make_all_cpus_request_except()
[ Upstream commit baff59ccdc657d290be51b95b38ebe5de40036b4 ]
Allocating cpumask dynamically in zalloc_cpumask_var() is not ideal.
Allocation is somewhat slow and can (in theory and when CPUMASK_OFFSTACK)
fail. kvm_make_all_cpus_request_except() already disables preemption so
we can use pre-allocated per-cpu cpumasks instead.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210903075141.403071-8-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Stable-dep-of: 2b0128127373 ("KVM: Register /dev/kvm as the _very_ last thing during initialization")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'virt/kvm/kvm_main.c')
| -rw-r--r-- | virt/kvm/kvm_main.c | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 34931443dafa..d96a076aef0d 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -154,6 +154,8 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm); static unsigned long long kvm_createvm_count; static unsigned long long kvm_active_vms; +static DEFINE_PER_CPU(cpumask_var_t, cpu_kick_mask); + __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, unsigned long start, unsigned long end) { @@ -327,14 +329,15 @@ bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req, struct kvm_vcpu *except) { struct kvm_vcpu *vcpu; - cpumask_var_t cpus; + struct cpumask *cpus; bool called; int i, me; - zalloc_cpumask_var(&cpus, GFP_ATOMIC); - me = get_cpu(); + cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask); + cpumask_clear(cpus); + kvm_for_each_vcpu(i, vcpu, kvm) { if (vcpu == except) continue; @@ -344,7 +347,6 @@ bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req, called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT)); put_cpu(); - free_cpumask_var(cpus); return called; } @@ -5002,9 +5004,17 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, goto out_free_3; } + for_each_possible_cpu(cpu) { + if (!alloc_cpumask_var_node(&per_cpu(cpu_kick_mask, cpu), + GFP_KERNEL, cpu_to_node(cpu))) { + r = -ENOMEM; + goto out_free_4; + } + } + r = kvm_async_pf_init(); if (r) - goto out_free; + goto out_free_5; kvm_chardev_ops.owner = module; kvm_vm_fops.owner = module; @@ -5030,7 +5040,10 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, out_unreg: kvm_async_pf_deinit(); -out_free: +out_free_5: + for_each_possible_cpu(cpu) + free_cpumask_var(per_cpu(cpu_kick_mask, cpu)); +out_free_4: kmem_cache_destroy(kvm_vcpu_cache); out_free_3: unregister_reboot_notifier(&kvm_reboot_notifier); @@ -5050,8 +5063,12 @@ EXPORT_SYMBOL_GPL(kvm_init); void kvm_exit(void) { + int cpu; + debugfs_remove_recursive(kvm_debugfs_dir); misc_deregister(&kvm_dev); + for_each_possible_cpu(cpu) + free_cpumask_var(per_cpu(cpu_kick_mask, cpu)); kmem_cache_destroy(kvm_vcpu_cache); kvm_async_pf_deinit(); unregister_syscore_ops(&kvm_syscore_ops); |