From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992900Ab2KOE1A (ORCPT ); Wed, 14 Nov 2012 23:27:00 -0500 Received: from mail.kernel.org ([198.145.19.201]:49561 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2993138Ab2KOEMQ (ORCPT ); Wed, 14 Nov 2012 23:12:16 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Jingjie Jiang , Mukesh Rathor , Konrad Rzeszutek Wilk Subject: [ 02/57] xen/mmu: Use Xen specific TLB flush instead of the generic one. Date: Wed, 14 Nov 2012 20:11:10 -0800 Message-Id: <20121115040933.375105830@linuxfoundation.org> X-Mailer: git-send-email 1.8.0.rc3.16.g8ead1bf In-Reply-To: <20121115040933.223998671@linuxfoundation.org> References: <20121115040933.223998671@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Konrad Rzeszutek Wilk commit 95a7d76897c1e7243d4137037c66d15cbf2cce76 upstream. As Mukesh explained it, the MMUEXT_TLB_FLUSH_ALL allows the hypervisor to do a TLB flush on all active vCPUs. If instead we were using the generic one (which ends up being xen_flush_tlb) we end up making the MMUEXT_TLB_FLUSH_LOCAL hypercall. But before we make that hypercall the kernel will IPI all of the vCPUs (even those that were asleep from the hypervisor perspective). The end result is that we needlessly wake them up and do a TLB flush when we can just let the hypervisor do it correctly. This patch gives around 50% speed improvement when migrating idle guest's from one host to another. Oracle-bug: 14630170 Tested-by: Jingjie Jiang Suggested-by: Mukesh Rathor Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman --- arch/x86/xen/mmu.c | 21 ++++++++++++++++++++- include/trace/events/xen.h | 8 ++++++++ 2 files changed, 28 insertions(+), 1 deletion(-) --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -1203,6 +1203,25 @@ unsigned long xen_read_cr2_direct(void) return this_cpu_read(xen_vcpu_info.arch.cr2); } +void xen_flush_tlb_all(void) +{ + struct mmuext_op *op; + struct multicall_space mcs; + + trace_xen_mmu_flush_tlb_all(0); + + preempt_disable(); + + mcs = xen_mc_entry(sizeof(*op)); + + op = mcs.args; + op->cmd = MMUEXT_TLB_FLUSH_ALL; + MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); + + xen_mc_issue(PARAVIRT_LAZY_MMU); + + preempt_enable(); +} static void xen_flush_tlb(void) { struct mmuext_op *op; @@ -2364,7 +2383,7 @@ int xen_remap_domain_mfn_range(struct vm err = 0; out: - flush_tlb_all(); + xen_flush_tlb_all(); return err; } --- a/include/trace/events/xen.h +++ b/include/trace/events/xen.h @@ -377,6 +377,14 @@ DECLARE_EVENT_CLASS(xen_mmu_pgd, DEFINE_XEN_MMU_PGD_EVENT(xen_mmu_pgd_pin); DEFINE_XEN_MMU_PGD_EVENT(xen_mmu_pgd_unpin); +TRACE_EVENT(xen_mmu_flush_tlb_all, + TP_PROTO(int x), + TP_ARGS(x), + TP_STRUCT__entry(__array(char, x, 0)), + TP_fast_assign((void)x), + TP_printk("%s", "") + ); + TRACE_EVENT(xen_mmu_flush_tlb, TP_PROTO(int x), TP_ARGS(x),