From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D867BECDFC1 for ; Sat, 28 Jul 2018 21:54:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9E94220893 for ; Sat, 28 Jul 2018 21:54:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9E94220893 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731535AbeG1XWh (ORCPT ); Sat, 28 Jul 2018 19:22:37 -0400 Received: from shelob.surriel.com ([96.67.55.147]:44166 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731425AbeG1XWW (ORCPT ); Sat, 28 Jul 2018 19:22:22 -0400 Received: from imladris.surriel.com ([96.67.55.152]) by shelob.surriel.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1fjXA0-0000QZ-T0; Sat, 28 Jul 2018 17:54:00 -0400 From: Rik van Riel To: linux-kernel@vger.kernel.org Cc: kernel-team@fb.com, peterz@infradead.org, luto@kernel.org, x86@kernel.org, vkuznets@redhat.com, mingo@kernel.org, efault@gmx.de, dave.hansen@intel.com, will.daecon@arm.com, catalin.marinas@arm.com, benh@kernel.crashing.org, Rik van Riel Subject: [PATCH 09/10] mm,x86: shoot down lazy TLB references at exit_mmap time Date: Sat, 28 Jul 2018 17:53:56 -0400 Message-Id: <20180728215357.3249-10-riel@surriel.com> X-Mailer: git-send-email 2.14.4 In-Reply-To: <20180728215357.3249-1-riel@surriel.com> References: <20180728215357.3249-1-riel@surriel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Shooting down lazy TLB references to an mm at exit_mmap time ensures that no users of the mm_struct will be left anywhere in the system, allowing it to be torn down and freed immediately. Signed-off-by: Rik van Riel Suggested-by: Andy Lutomirski Suggested-by: Peter Zijlstra --- arch/x86/Kconfig | 1 + arch/x86/include/asm/mmu_context.h | 1 + arch/x86/include/asm/tlbflush.h | 2 ++ arch/x86/mm/tlb.c | 15 +++++++++++++++ 4 files changed, 19 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 6d4774f203d0..ecdfc6933203 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -75,6 +75,7 @@ config X86 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI select ARCH_MIGHT_HAVE_PC_PARPORT select ARCH_MIGHT_HAVE_PC_SERIO + select ARCH_NO_ACTIVE_MM_REFCOUNTING select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 select ARCH_USE_BUILTIN_BSWAP diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index eeeb9289c764..529bf7bc5f75 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -238,6 +238,7 @@ static inline void arch_exit_mmap(struct mm_struct *mm) { paravirt_arch_exit_mmap(mm); ldt_arch_exit_mmap(mm); + lazy_tlb_exit_mmap(mm); } #ifdef CONFIG_X86_64 diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 511bf5fae8b8..3966a45367cd 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -538,6 +538,8 @@ extern void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch); native_flush_tlb_others(mask, info) #endif +extern void lazy_tlb_exit_mmap(struct mm_struct *mm); + extern void tlb_flush_remove_tables(struct mm_struct *mm); extern void tlb_flush_remove_tables_local(void *arg); diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index ea4ef5ceaba2..7b1add904396 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -713,6 +713,21 @@ void tlb_flush_remove_tables(struct mm_struct *mm) put_cpu(); } +/* + * At exit or execve time, all other threads of a process have disappeared, + * but other CPUs could still be referencing this mm in lazy TLB mode. + * Get rid of those references before releasing the mm. + */ +void lazy_tlb_exit_mmap(struct mm_struct *mm) +{ + int cpu = get_cpu(); + + if (cpumask_any_but(mm_cpumask(mm), cpu) < nr_cpu_ids) + on_each_cpu_mask(mm_cpumask(mm), leave_mm, NULL, 1); + + put_cpu(); +} + static void do_flush_tlb_all(void *info) { count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED); -- 2.14.4