From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754405Ab3JXJTN (ORCPT ); Thu, 24 Oct 2013 05:19:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63688 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754051Ab3JXJTM (ORCPT ); Thu, 24 Oct 2013 05:19:12 -0400 Date: Thu, 24 Oct 2013 12:19:05 +0300 From: Gleb Natapov To: Xiao Guangrong Cc: avi.kivity@gmail.com, mtosatti@redhat.com, pbonzini@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH v3 10/15] KVM: MMU: allocate shadow pages from slab Message-ID: <20131024091905.GB5289@redhat.com> References: <1382534973-13197-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> <1382534973-13197-11-git-send-email-xiaoguangrong@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1382534973-13197-11-git-send-email-xiaoguangrong@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 23, 2013 at 09:29:28PM +0800, Xiao Guangrong wrote: > Allocate shadow pages from slab instead of page-allocator, frequent > shadow page allocation and free can be hit in the slab cache, it is > very useful for shadow mmu > > Signed-off-by: Xiao Guangrong > --- > arch/x86/include/asm/kvm_host.h | 3 ++- > arch/x86/kvm/mmu.c | 46 ++++++++++++++++++++++++++++++++++------- > 2 files changed, 41 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 5cbf316..df9ae10 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -389,6 +389,7 @@ struct kvm_vcpu_arch { > struct kvm_mmu *walk_mmu; > > struct kvm_mmu_memory_cache mmu_pte_list_desc_cache; > + struct kvm_mmu_memory_cache mmu_shadow_page_cache; > struct kvm_mmu_memory_cache mmu_page_cache; > struct kvm_mmu_memory_cache mmu_page_header_cache; > > @@ -946,7 +947,7 @@ static inline struct kvm_mmu_page *page_header(hpa_t shadow_page) > { > struct page *page = pfn_to_page(shadow_page >> PAGE_SHIFT); > > - return (struct kvm_mmu_page *)page_private(page); > + return (struct kvm_mmu_page *)(page->mapping); Why? > } > > static inline u16 kvm_read_ldt(void) > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index f3ae74e6..1bcc8c8 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -178,6 +178,7 @@ struct kvm_shadow_walk_iterator { > __shadow_walk_next(&(_walker), spte)) > > static struct kmem_cache *pte_list_desc_cache; > +static struct kmem_cache *mmu_shadow_page_cache; > static struct kmem_cache *mmu_page_header_cache; > static struct percpu_counter kvm_total_used_mmu_pages; > > @@ -746,7 +747,14 @@ static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu) > GFP_KERNEL); > if (r) > goto out; > - r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8); > + > + r = mmu_topup_memory_cache(&vcpu->arch.mmu_shadow_page_cache, > + mmu_shadow_page_cache, 4, > + GFP_KERNEL); > + if (r) > + goto out; > + > + r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 4); > if (r) > goto out; > r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache, > @@ -760,6 +768,8 @@ static void mmu_free_memory_caches(struct kvm_vcpu *vcpu) > { > mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache, > pte_list_desc_cache); > + mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache, > + mmu_shadow_page_cache); > mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache); > mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache, > mmu_page_header_cache); > @@ -1675,12 +1685,28 @@ static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, int nr) > percpu_counter_add(&kvm_total_used_mmu_pages, nr); > } > > +static void set_page_header(struct kvm_mmu_page *sp) > +{ > + struct page *page = virt_to_page(sp->spt); > + > + WARN_ON(page->mapping); > + page->mapping = (struct address_space *)sp; > +} > + > +static void clear_page_header(struct kvm_mmu_page *sp) > +{ > + struct page *page = virt_to_page(sp->spt); > + > + page->mapping = NULL; > +} > + > static void kvm_mmu_free_page(struct kvm_mmu_page *sp) > { > ASSERT(is_empty_shadow_page(sp->spt)); > hlist_del(&sp->hash_link); > list_del(&sp->link); > - free_page((unsigned long)sp->spt); > + clear_page_header(sp); > + kmem_cache_free(mmu_shadow_page_cache, sp->spt); > if (!sp->role.direct) > free_page((unsigned long)sp->gfns); > kmem_cache_free(mmu_page_header_cache, sp); > @@ -1719,10 +1745,10 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, > struct kvm_mmu_page *sp; > > sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); > - sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache); > + sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); > if (!direct) > sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache); > - set_page_private(virt_to_page(sp->spt), (unsigned long)sp); > + set_page_header(sp); > > /* > * The active_mmu_pages list is the FIFO list, do not move the > @@ -2046,12 +2072,13 @@ static void mmu_sync_children(struct kvm_vcpu *vcpu, > } > } > > -static void init_shadow_page_table(struct kvm_mmu_page *sp) > +static void init_shadow_page_table(void *p) > { > + u64 *sptp = (u64 *)p; > int i; > > for (i = 0; i < PT64_ENT_PER_PAGE; ++i) > - sp->spt[i] = 0ull; > + sptp[i] = 0ull; > } > > static void __clear_sp_write_flooding_count(struct kvm_mmu_page *sp) > @@ -2137,7 +2164,6 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, > account_shadowed(vcpu->kvm, gfn); > } > sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; > - init_shadow_page_table(sp); > trace_kvm_mmu_get_page(sp, true); > return sp; > } > @@ -4683,6 +4709,12 @@ int kvm_mmu_module_init(void) > if (!pte_list_desc_cache) > goto nomem; > > + mmu_shadow_page_cache = kmem_cache_create("mmu_shadow_page_cache", > + PAGE_SIZE, PAGE_SIZE, 0, > + init_shadow_page_table); > + if (!mmu_shadow_page_cache) > + goto nomem; > + > mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header", > sizeof(struct kvm_mmu_page), > 0, 0, NULL); > -- > 1.8.1.4 -- Gleb.