| Message ID | 20090108182617.GA7250@amt.cnet (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
Marcelo Tosatti wrote: > Clean the pre-allocated cache pages before entering mmu_lock region. > This is safe since the caches are per-vcpu. > > Smaller chunks are already zeroed by kmem_cache_zalloc. > > ~= 0.90% reduction in system time with AIM7 on RHEL3 / 4-vcpu. > > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index 10bdb2a..823d0cd 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -301,7 +301,7 @@ static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache, > if (cache->nobjs >= min) > return 0; > while (cache->nobjs < ARRAY_SIZE(cache->objects)) { > - page = alloc_page(GFP_KERNEL); > + page = alloc_page(GFP_KERNEL|__GFP_ZERO); > if (!page) > return -ENOMEM; > set_page_private(page, 0); > @@ -352,7 +352,6 @@ static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc, > > BUG_ON(!mc->nobjs); > p = mc->objects[--mc->nobjs]; > - memset(p, 0, size); > return p; > } > > I think we can drop the memset altogether, since we will clear the page in ->prefetch_page() anyway.
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 10bdb2a..823d0cd 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -301,7 +301,7 @@ static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache, if (cache->nobjs >= min) return 0; while (cache->nobjs < ARRAY_SIZE(cache->objects)) { - page = alloc_page(GFP_KERNEL); + page = alloc_page(GFP_KERNEL|__GFP_ZERO); if (!page) return -ENOMEM; set_page_private(page, 0); @@ -352,7 +352,6 @@ static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc, BUG_ON(!mc->nobjs); p = mc->objects[--mc->nobjs]; - memset(p, 0, size); return p; }
Clean the pre-allocated cache pages before entering mmu_lock region. This is safe since the caches are per-vcpu. Smaller chunks are already zeroed by kmem_cache_zalloc. ~= 0.90% reduction in system time with AIM7 on RHEL3 / 4-vcpu. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html