From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754317AbZBRWbE (ORCPT ); Wed, 18 Feb 2009 17:31:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752957AbZBRWaY (ORCPT ); Wed, 18 Feb 2009 17:30:24 -0500 Received: from adsl-76-233-236-102.dsl.pltn13.sbcglobal.net ([76.233.236.102]:43888 "EHLO abulafia.goop.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752447AbZBRWaX (ORCPT ); Wed, 18 Feb 2009 17:30:23 -0500 From: Jeremy Fitzhardinge To: Ingo Molnar Cc: the arch/x86 maintainers , Xen-devel , Linux Kernel Mailing List , Peter Zijlstra , Nick Piggin , Andrew Morton , Thomas Gleixner , Rusty Russell , Zachary Amsden , Alok N Kataria , Avi Kivity , Marcelo Tosatti , Jeremy Fitzhardinge Subject: [PATCH 6/9] x86/paravirt: allow preemption with lazy mmu mode Date: Wed, 18 Feb 2009 14:30:15 -0800 Message-Id: X-Mailer: git-send-email 1.6.0.6 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jeremy Fitzhardinge Lift restrictions on preemption with lazy mmu mode, as it is now allowed. Signed-off-by: Jeremy Fitzhardinge --- arch/x86/kernel/paravirt.c | 7 ++++--- arch/x86/xen/mmu.c | 8 +------- 2 files changed, 5 insertions(+), 10 deletions(-) diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index 554dadd..1a81ce9 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -248,7 +248,6 @@ static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LA static inline void enter_lazy(enum paravirt_lazy_mode mode) { BUG_ON(__get_cpu_var(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); - BUG_ON(preemptible()); __get_cpu_var(paravirt_lazy_mode) = mode; } @@ -256,7 +255,6 @@ static inline void enter_lazy(enum paravirt_lazy_mode mode) static void leave_lazy(enum paravirt_lazy_mode mode) { BUG_ON(__get_cpu_var(paravirt_lazy_mode) != mode); - BUG_ON(preemptible()); __get_cpu_var(paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; } @@ -273,6 +271,8 @@ void paravirt_leave_lazy_mmu(void) void paravirt_enter_lazy_cpu(void) { + BUG_ON(preemptible()); + if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { arch_leave_lazy_mmu_mode(); set_thread_flag(TIF_LAZY_MMU_UPDATES); @@ -282,6 +282,8 @@ void paravirt_enter_lazy_cpu(void) void paravirt_leave_lazy_cpu(void) { + BUG_ON(preemptible()); + leave_lazy(PARAVIRT_LAZY_CPU); if (test_and_clear_thread_flag(TIF_LAZY_MMU_UPDATES)) @@ -301,7 +303,6 @@ void arch_flush_lazy_mmu_mode(void) preempt_disable(); if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { - WARN_ON(preempt_count() == 1); arch_leave_lazy_mmu_mode(); arch_enter_lazy_mmu_mode(); } diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 2669c58..92c6463 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -412,10 +412,6 @@ void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags) void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval) { - /* updates to init_mm may be done without lock */ - if (mm == &init_mm) - preempt_disable(); - ADD_STATS(set_pte_at, 1); // ADD_STATS(set_pte_at_pinned, xen_page_pinned(ptep)); ADD_STATS(set_pte_at_current, mm == current->mm); @@ -436,9 +432,7 @@ void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, } xen_set_pte(ptep, pteval); -out: - if (mm == &init_mm) - preempt_enable(); +out: return; } pte_t xen_ptep_modify_prot_start(struct mm_struct *mm, -- 1.6.0.6