From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: KVM: MMU: zero caches before entering mmu_lock protected section Date: Thu, 8 Jan 2009 16:26:17 -0200 Message-ID: <20090108182617.GA7250@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Avi Kivity To: kvm@vger.kernel.org Return-path: Received: from mx2.redhat.com ([66.187.237.31]:44316 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752228AbZAHS0l (ORCPT ); Thu, 8 Jan 2009 13:26:41 -0500 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n08IQRUi005092 for ; Thu, 8 Jan 2009 13:26:27 -0500 Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: 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 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; }