From: Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: kvm@vger.kernel.org, Marcelo Tosatti <mtosatti@redhat.com>
Subject: [patch 2/4] KVM: MMU: collapse remote TLB flushes on root sync
Date: Mon, 01 Dec 2008 22:32:03 -0200 [thread overview]
Message-ID: <20081202003333.674155915@localhost.localdomain> (raw)
In-Reply-To: 20081202003201.739616208@localhost.localdomain
[-- Attachment #1: kvm-collapse-tlb-flush --]
[-- Type: text/plain, Size: 2002 bytes --]
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>
Index: kvm/arch/x86/kvm/mmu.c
===================================================================
--- kvm.orig/arch/x86/kvm/mmu.c
+++ kvm/arch/x86/kvm/mmu.c
@@ -621,7 +621,7 @@ static u64 *rmap_next(struct kvm *kvm, u
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 kv
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
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
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_
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)
--
next prev parent reply other threads:[~2008-12-02 0:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-02 0:32 [patch 0/4] oos shadow optimizations v2 Marcelo Tosatti
2008-12-02 0:32 ` [patch 1/4] KVM: MMU: use page array in unsync walk Marcelo Tosatti
2008-12-02 0:32 ` Marcelo Tosatti [this message]
2008-12-02 0:32 ` [patch 3/4] KVM: MMU: skip global pgtables on sync due to cr3 switch Marcelo Tosatti
2008-12-02 0:32 ` [patch 4/4] KVM: MMU: prepopulate the shadow on invlpg Marcelo Tosatti
2008-12-05 17:57 ` [patch 0/4] oos shadow optimizations v2 Avi Kivity
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