From c142786c6291189b5c85f53d91743e1eefbd8fe0 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Mon, 14 May 2012 15:44:06 +0300 Subject: KVM: MMU: Don't use RCU for lockless shadow walking Using RCU for lockless shadow walking can increase the amount of memory in use by the system, since RCU grace periods are unpredictable. We also have an unconditional write to a shared variable (reader_counter), which isn't good for scaling. Replace that with a scheme similar to x86's get_user_pages_fast(): disable interrupts during lockless shadow walk to force the freer (kvm_mmu_commit_zap_page()) to wait for the TLB flush IPI to find the processor with interrupts enabled. We also add a new vcpu->mode, READING_SHADOW_PAGE_TABLES, to prevent kvm_flush_remote_tlbs() from avoiding the IPI. Signed-off-by: Avi Kivity Signed-off-by: Marcelo Tosatti --- include/linux/kvm_host.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index cae342d29d1b..c4464356b35b 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -128,7 +128,8 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); enum { OUTSIDE_GUEST_MODE, IN_GUEST_MODE, - EXITING_GUEST_MODE + EXITING_GUEST_MODE, + READING_SHADOW_PAGE_TABLES, }; /* -- cgit v1.2.2