lkml.org 
[lkml]   [2008]   [Dec]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 33/36] KVM: MMU: collapse remote TLB flushes on root sync
Date
From: Marcelo Tosatti <mtosatti@redhat.com>

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>
---
arch/x86/kvm/mmu.c | 19 ++++++++++++++-----
1 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 7ce92f7..58c35de 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)
--
1.6.0.3


\
 
 \ /
  Last update: 2008-12-14 09:17    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site