Messages in this thread Patch in this message | | | From | Xiao Guangrong <> | Subject | [PATCH v4 6/6] KVM: MMU: make kvm_mmu_zap_all preemptable | Date | Sat, 27 Apr 2013 11:13:22 +0800 |
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Now, kvm_mmu_zap_all is only called in the path of mmu_notifier->release, at that time, vcpu has stopped that means no new page will be create, we can use lock-break technique to avoid potential soft lockup
(Note: at this time, the mmu-lock still has contention between ->release and other mmu-notify handlers.)
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> --- arch/x86/kvm/mmu.c | 11 ++++++++++- 1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 63110c7..46d1d47 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4197,12 +4197,21 @@ void kvm_mmu_zap_all(struct kvm *kvm) struct kvm_mmu_page *sp, *node; LIST_HEAD(invalid_list); + might_sleep(); + spin_lock(&kvm->mmu_lock); restart: - list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link) + list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link) { if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list)) goto restart; + if (need_resched() || spin_needbreak(&kvm->mmu_lock)) { + kvm_mmu_commit_zap_page(kvm, &invalid_list); + cond_resched_lock(&kvm->mmu_lock); + goto restart; + } + } + kvm_mmu_commit_zap_page(kvm, &invalid_list); spin_unlock(&kvm->mmu_lock); } -- 1.7.7.6
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