Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964832Ab3DKAbe (ORCPT ); Wed, 10 Apr 2013 20:31:34 -0400 Received: from terminus.zytor.com ([198.137.202.10]:36479 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934913Ab3DKAbc (ORCPT ); Wed, 10 Apr 2013 20:31:32 -0400 Date: Wed, 10 Apr 2013 17:30:32 -0700 From: tip-bot for Boris Ostrovsky Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, konrad.wilk@oracle.com, boris.ostrovsky@oracle.com, jwboyer@redhat.com, tglx@linutronix.de, hpa@linux.intel.com, bp@suse.de Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, konrad.wilk@oracle.com, boris.ostrovsky@oracle.com, jwboyer@redhat.com, tglx@linutronix.de, bp@suse.de, hpa@linux.intel.com In-Reply-To: <1364045796-10720-2-git-send-email-konrad.wilk@oracle.com> References: <1364045796-10720-2-git-send-email-konrad.wilk@oracle.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86, mm: Patch out arch_flush_lazy_mmu_mode() when running on bare metal Git-Commit-ID: 511ba86e1d386f671084b5d0e6f110bb30b8eeb2 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (terminus.zytor.com [127.0.0.1]); Wed, 10 Apr 2013 17:30:38 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5187 Lines: 152 Commit-ID: 511ba86e1d386f671084b5d0e6f110bb30b8eeb2 Gitweb: http://git.kernel.org/tip/511ba86e1d386f671084b5d0e6f110bb30b8eeb2 Author: Boris Ostrovsky AuthorDate: Sat, 23 Mar 2013 09:36:36 -0400 Committer: H. Peter Anvin CommitDate: Wed, 10 Apr 2013 11:25:10 -0700 x86, mm: Patch out arch_flush_lazy_mmu_mode() when running on bare metal Invoking arch_flush_lazy_mmu_mode() results in calls to preempt_enable()/disable() which may have performance impact. Since lazy MMU is not used on bare metal we can patch away arch_flush_lazy_mmu_mode() so that it is never called in such environment. [ hpa: the previous patch "Fix vmalloc_fault oops during lazy MMU updates" may cause a minor performance regression on bare metal. This patch resolves that performance regression. It is somewhat unclear to me if this is a good -stable candidate. ] Signed-off-by: Boris Ostrovsky Link: http://lkml.kernel.org/r/1364045796-10720-2-git-send-email-konrad.wilk@oracle.com Tested-by: Josh Boyer Tested-by: Konrad Rzeszutek Wilk Acked-by: Borislav Petkov Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: H. Peter Anvin Cc: SEE NOTE ABOVE --- arch/x86/include/asm/paravirt.h | 5 ++++- arch/x86/include/asm/paravirt_types.h | 2 ++ arch/x86/kernel/paravirt.c | 25 +++++++++++++------------ arch/x86/lguest/boot.c | 1 + arch/x86/xen/mmu.c | 1 + 5 files changed, 21 insertions(+), 13 deletions(-) diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 5edd174..7361e47 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -703,7 +703,10 @@ static inline void arch_leave_lazy_mmu_mode(void) PVOP_VCALL0(pv_mmu_ops.lazy_mode.leave); } -void arch_flush_lazy_mmu_mode(void); +static inline void arch_flush_lazy_mmu_mode(void) +{ + PVOP_VCALL0(pv_mmu_ops.lazy_mode.flush); +} static inline void __set_fixmap(unsigned /* enum fixed_addresses */ idx, phys_addr_t phys, pgprot_t flags) diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 142236e..b3b0ec1 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -91,6 +91,7 @@ struct pv_lazy_ops { /* Set deferred update mode, used for batching operations. */ void (*enter)(void); void (*leave)(void); + void (*flush)(void); }; struct pv_time_ops { @@ -679,6 +680,7 @@ void paravirt_end_context_switch(struct task_struct *next); void paravirt_enter_lazy_mmu(void); void paravirt_leave_lazy_mmu(void); +void paravirt_flush_lazy_mmu(void); void _paravirt_nop(void); u32 _paravirt_ident_32(u32); diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index 17fff18..8bfb335 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -263,6 +263,18 @@ void paravirt_leave_lazy_mmu(void) leave_lazy(PARAVIRT_LAZY_MMU); } +void paravirt_flush_lazy_mmu(void) +{ + preempt_disable(); + + if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { + arch_leave_lazy_mmu_mode(); + arch_enter_lazy_mmu_mode(); + } + + preempt_enable(); +} + void paravirt_start_context_switch(struct task_struct *prev) { BUG_ON(preemptible()); @@ -292,18 +304,6 @@ enum paravirt_lazy_mode paravirt_get_lazy_mode(void) return this_cpu_read(paravirt_lazy_mode); } -void arch_flush_lazy_mmu_mode(void) -{ - preempt_disable(); - - if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { - arch_leave_lazy_mmu_mode(); - arch_enter_lazy_mmu_mode(); - } - - preempt_enable(); -} - struct pv_info pv_info = { .name = "bare hardware", .paravirt_enabled = 0, @@ -475,6 +475,7 @@ struct pv_mmu_ops pv_mmu_ops = { .lazy_mode = { .enter = paravirt_nop, .leave = paravirt_nop, + .flush = paravirt_nop, }, .set_fixmap = native_set_fixmap, diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 1cbd89c..7114c63 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -1334,6 +1334,7 @@ __init void lguest_init(void) pv_mmu_ops.read_cr3 = lguest_read_cr3; pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu; pv_mmu_ops.lazy_mode.leave = lguest_leave_lazy_mmu_mode; + pv_mmu_ops.lazy_mode.flush = paravirt_flush_lazy_mmu; pv_mmu_ops.pte_update = lguest_pte_update; pv_mmu_ops.pte_update_defer = lguest_pte_update; diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 6afbb2c..2f5d687 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -2196,6 +2196,7 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = { .lazy_mode = { .enter = paravirt_enter_lazy_mmu, .leave = xen_leave_lazy_mmu, + .flush = paravirt_flush_lazy_mmu, }, .set_fixmap = xen_set_fixmap, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/