Messages in this thread | | | Date | Wed, 07 Aug 2013 21:19:53 +0800 | From | Xiao Guangrong <> | Subject | Re: [PATCH 10/12] KVM: MMU: allow locklessly access shadow page table out of vcpu thread |
| |
On 08/07/2013 09:09 PM, Takuya Yoshikawa wrote: > On Tue, 30 Jul 2013 21:02:08 +0800 > Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> wrote: > >> @@ -2342,6 +2358,13 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm, >> */ >> kvm_flush_remote_tlbs(kvm); >> >> + if (kvm->arch.rcu_free_shadow_page) { >> + sp = list_first_entry(invalid_list, struct kvm_mmu_page, link); >> + list_del_init(invalid_list); >> + call_rcu(&sp->rcu, free_pages_rcu); >> + return; >> + } >> + >> list_for_each_entry_safe(sp, nsp, invalid_list, link) { >> WARN_ON(!sp->role.invalid || sp->root_count); >> kvm_mmu_free_page(sp); > > Shouldn't we avoid calling call_rcu() when we are holding mmu_lock?
Using call_rcu() to free pages is a rare case that happen only between lockless write-protection and zapping shadow pages, so i think we do not need to care this case too much.
| |