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authorMarcelo Tosatti <mtosatti@redhat.com>2008-12-01 22:32:03 -0200
committerAvi Kivity <avi@redhat.com>2008-12-31 16:55:43 +0200
commitb1a368218ad5b6e62380c8f206f16e6f18bf154c (patch)
tree4c13c3bd259032d19255637dcff4001e970de6ae /arch/x86
parent60c8aec6e2c9923492dabbd6b67e34692bd26c20 (diff)
KVM: MMU: collapse remote TLB flushes on root sync
Collapse remote TLB flushes on root sync. kernbench is 2.7% faster on 4-way guest. Improvements have been seen with other loads such as AIM7. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/mmu.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 7ce92f78f33..58c35dead32 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -621,7 +621,7 @@ static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
return NULL;
}
-static void rmap_write_protect(struct kvm *kvm, u64 gfn)
+static int rmap_write_protect(struct kvm *kvm, u64 gfn)
{
unsigned long *rmapp;
u64 *spte;
@@ -667,8 +667,7 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn)
spte = rmap_next(kvm, rmapp, spte);
}
- if (write_protected)
- kvm_flush_remote_tlbs(kvm);
+ return write_protected;
}
static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp)
@@ -1083,7 +1082,8 @@ static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
return 1;
}
- rmap_write_protect(vcpu->kvm, sp->gfn);
+ if (rmap_write_protect(vcpu->kvm, sp->gfn))
+ kvm_flush_remote_tlbs(vcpu->kvm);
kvm_unlink_unsync_page(vcpu->kvm, sp);
if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
kvm_mmu_zap_page(vcpu->kvm, sp);
@@ -1162,6 +1162,14 @@ static void mmu_sync_children(struct kvm_vcpu *vcpu,
kvm_mmu_pages_init(parent, &parents, &pages);
while (mmu_unsync_walk(parent, &pages)) {
+ int protected = 0;
+
+ for_each_sp(pages, sp, parents, i)
+ protected |= rmap_write_protect(vcpu->kvm, sp->gfn);
+
+ if (protected)
+ kvm_flush_remote_tlbs(vcpu->kvm);
+
for_each_sp(pages, sp, parents, i) {
kvm_sync_page(vcpu, sp);
mmu_pages_clear_parents(&parents);
@@ -1226,7 +1234,8 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
sp->role = role;
hlist_add_head(&sp->hash_link, bucket);
if (!metaphysical) {
- rmap_write_protect(vcpu->kvm, gfn);
+ if (rmap_write_protect(vcpu->kvm, gfn))
+ kvm_flush_remote_tlbs(vcpu->kvm);
account_shadowed(vcpu->kvm, gfn);
}
if (shadow_trap_nonpresent_pte != shadow_notrap_nonpresent_pte)