From patchwork Tue Feb 9 22:16:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 12079393 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 BE505C433DB for ; Tue, 9 Feb 2021 23:22:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DC1B64E3E for ; Tue, 9 Feb 2021 23:22:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234513AbhBIXT4 (ORCPT ); Tue, 9 Feb 2021 18:19:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58858 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233680AbhBIWYf (ORCPT ); Tue, 9 Feb 2021 17:24:35 -0500 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7625AC0617A9; Tue, 9 Feb 2021 14:21:22 -0800 (PST) Received: by mail-pl1-x631.google.com with SMTP id x9so86152plb.5; Tue, 09 Feb 2021 14:21:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=jOyYx1TDjb2A4gHSVOiGYO/bJUu5bLpN/42e2o+FxXM=; b=ZudShlgecDcgL2Wf7EG99R2XM3pqdJk3GWkX8vluBL6fzf8DqgL/EzorucwyMsx473 cWp4bOxGdoorhZtXy7Tr0y1KlPEImuVeXVMi3aIYKeYFmsEGAWYZ4r1y5xDQglrr889X NL7wsA8Vp6Tak9bbZi4PWSpfHM5dcxpZ9rkveVr53WNiLM//4j+SpsZXoB5wdDi4C+dI NN+OA9jejs5MTmkLQKWHNCRrHffajpvUi6XNEXyxRG9f9fvB8a0qHZxPuNYKe61jRasg MIAm1hLLu6hshupMPGoLrP0BL9DLL3SmxlC1gHjdFuC4JmTPNsiwBdutV/opH2MChwlF 4oHQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=jOyYx1TDjb2A4gHSVOiGYO/bJUu5bLpN/42e2o+FxXM=; b=Vnej6H6w6lC4esHwLVC4e97FFS0D9NdVpp32jtD6h2rlW/zV19Lz1b5giyZWYZJV5e NhvmlVGKnh58+WGQZ0oe9yK+W1jT9pO1LsM7CuCmc2jCrMlKSJ8E/7FHNQjiit2DZ+7F 6IAkqKrEeS1ADVgMlllUpT0SFTxpRCphGRRgpNc4ZU1noeVO/Qhq41HM5hG7qwPO5MiL 20wBhcBLa6+STIkNZlLUz4SKIJd4XWPDzeu+ewSPfpbJpnG6xenKWt2tq7beb+7YwpEV Vfq0nMnipyWJrSSvqSARR8+e36pljUukLBd+85u/L8+QO+GTL+VaUX+cAFId3kNX9jha 2Scg== X-Gm-Message-State: AOAM530bGmLYeayuDGgaCxeL8JLuUsPu9JdkYNmvzTPGOrXXZ1kWOG97 B739eRDp/RWhjrgplKsDNFU= X-Google-Smtp-Source: ABdhPJwGDIgAQd0D3Bj7K7xE4Obh8SaZ1xW5cnD9EhQUhLiG0OIrXKXpw3elA2mYDupV4v1VuXjmJQ== X-Received: by 2002:a17:90a:fc3:: with SMTP id 61mr8462pjz.197.1612909281819; Tue, 09 Feb 2021 14:21:21 -0800 (PST) Received: from sc2-haas01-esx0118.eng.vmware.com ([66.170.99.1]) by smtp.gmail.com with ESMTPSA id v9sm58601pju.33.2021.02.09.14.21.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Feb 2021 14:21:21 -0800 (PST) From: Nadav Amit X-Google-Original-From: Nadav Amit To: Thomas Gleixner Cc: linux-kernel@vger.kernel.org, Andy Lutomirski , Peter Zijlstra , Dave Hansen , Nadav Amit , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Sasha Levin , Ingo Molnar , Borislav Petkov , x86@kernel.org, Juergen Gross , Paolo Bonzini , Boris Ostrovsky , linux-hyperv@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, Michael Kelley Subject: [PATCH v5 4/8] x86/mm/tlb: Flush remote and local TLBs concurrently Date: Tue, 9 Feb 2021 14:16:49 -0800 Message-Id: <20210209221653.614098-5-namit@vmware.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210209221653.614098-1-namit@vmware.com> References: <20210209221653.614098-1-namit@vmware.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Nadav Amit To improve TLB shootdown performance, flush the remote and local TLBs concurrently. Introduce flush_tlb_multi() that does so. Introduce paravirtual versions of flush_tlb_multi() for KVM, Xen and hyper-v (Xen and hyper-v are only compile-tested). While the updated smp infrastructure is capable of running a function on a single local core, it is not optimized for this case. The multiple function calls and the indirect branch introduce some overhead, and might make local TLB flushes slower than they were before the recent changes. Before calling the SMP infrastructure, check if only a local TLB flush is needed to restore the lost performance in this common case. This requires to check mm_cpumask() one more time, but unless this mask is updated very frequently, this should impact performance negatively. Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Sasha Levin Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: x86@kernel.org Cc: Juergen Gross Cc: Paolo Bonzini Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Boris Ostrovsky Cc: linux-hyperv@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Cc: kvm@vger.kernel.org Cc: xen-devel@lists.xenproject.org Reviewed-by: Michael Kelley # Hyper-v parts Reviewed-by: Juergen Gross # Xen and paravirt parts Reviewed-by: Dave Hansen Signed-off-by: Nadav Amit --- arch/x86/hyperv/mmu.c | 10 +++--- arch/x86/include/asm/paravirt.h | 6 ++-- arch/x86/include/asm/paravirt_types.h | 4 +-- arch/x86/include/asm/tlbflush.h | 4 +-- arch/x86/include/asm/trace/hyperv.h | 2 +- arch/x86/kernel/kvm.c | 11 ++++-- arch/x86/mm/tlb.c | 49 +++++++++++++++++---------- arch/x86/xen/mmu_pv.c | 11 +++--- include/trace/events/xen.h | 2 +- 9 files changed, 58 insertions(+), 41 deletions(-) diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c index 2c87350c1fb0..681dba8de4f2 100644 --- a/arch/x86/hyperv/mmu.c +++ b/arch/x86/hyperv/mmu.c @@ -52,8 +52,8 @@ static inline int fill_gva_list(u64 gva_list[], int offset, return gva_n - offset; } -static void hyperv_flush_tlb_others(const struct cpumask *cpus, - const struct flush_tlb_info *info) +static void hyperv_flush_tlb_multi(const struct cpumask *cpus, + const struct flush_tlb_info *info) { int cpu, vcpu, gva_n, max_gvas; struct hv_tlb_flush **flush_pcpu; @@ -61,7 +61,7 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus, u64 status = U64_MAX; unsigned long flags; - trace_hyperv_mmu_flush_tlb_others(cpus, info); + trace_hyperv_mmu_flush_tlb_multi(cpus, info); if (!hv_hypercall_pg) goto do_native; @@ -164,7 +164,7 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus, if (!(status & HV_HYPERCALL_RESULT_MASK)) return; do_native: - native_flush_tlb_others(cpus, info); + native_flush_tlb_multi(cpus, info); } static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus, @@ -239,6 +239,6 @@ void hyperv_setup_mmu_ops(void) return; pr_info("Using hypercall for remote TLB flush\n"); - pv_ops.mmu.flush_tlb_others = hyperv_flush_tlb_others; + pv_ops.mmu.flush_tlb_multi = hyperv_flush_tlb_multi; pv_ops.mmu.tlb_remove_table = tlb_remove_table; } diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index f8dce11d2bc1..515e49204c8b 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -50,7 +50,7 @@ static inline void slow_down_io(void) void native_flush_tlb_local(void); void native_flush_tlb_global(void); void native_flush_tlb_one_user(unsigned long addr); -void native_flush_tlb_others(const struct cpumask *cpumask, +void native_flush_tlb_multi(const struct cpumask *cpumask, const struct flush_tlb_info *info); static inline void __flush_tlb_local(void) @@ -68,10 +68,10 @@ static inline void __flush_tlb_one_user(unsigned long addr) PVOP_VCALL1(mmu.flush_tlb_one_user, addr); } -static inline void __flush_tlb_others(const struct cpumask *cpumask, +static inline void __flush_tlb_multi(const struct cpumask *cpumask, const struct flush_tlb_info *info) { - PVOP_VCALL2(mmu.flush_tlb_others, cpumask, info); + PVOP_VCALL2(mmu.flush_tlb_multi, cpumask, info); } static inline void paravirt_tlb_remove_table(struct mmu_gather *tlb, void *table) diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index b6b02b7c19cc..541fe7193526 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -201,8 +201,8 @@ struct pv_mmu_ops { void (*flush_tlb_user)(void); void (*flush_tlb_kernel)(void); void (*flush_tlb_one_user)(unsigned long addr); - void (*flush_tlb_others)(const struct cpumask *cpus, - const struct flush_tlb_info *info); + void (*flush_tlb_multi)(const struct cpumask *cpus, + const struct flush_tlb_info *info); void (*tlb_remove_table)(struct mmu_gather *tlb, void *table); diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index a7a598af116d..3c6681def912 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -175,7 +175,7 @@ extern void initialize_tlbstate_and_flush(void); * - flush_tlb_page(vma, vmaddr) flushes one page * - flush_tlb_range(vma, start, end) flushes a range of pages * - flush_tlb_kernel_range(start, end) flushes a range of kernel pages - * - flush_tlb_others(cpumask, info) flushes TLBs on other cpus + * - flush_tlb_multi(cpumask, info) flushes TLBs on multiple cpus * * ..but the i386 has somewhat limited tlb flushing capabilities, * and page-granular flushes are available only on i486 and up. @@ -209,7 +209,7 @@ struct flush_tlb_info { void flush_tlb_local(void); void flush_tlb_one_user(unsigned long addr); void flush_tlb_one_kernel(unsigned long addr); -void flush_tlb_others(const struct cpumask *cpumask, +void flush_tlb_multi(const struct cpumask *cpumask, const struct flush_tlb_info *info); #ifdef CONFIG_PARAVIRT diff --git a/arch/x86/include/asm/trace/hyperv.h b/arch/x86/include/asm/trace/hyperv.h index 4d705cb4d63b..a8e5a7a2b460 100644 --- a/arch/x86/include/asm/trace/hyperv.h +++ b/arch/x86/include/asm/trace/hyperv.h @@ -8,7 +8,7 @@ #if IS_ENABLED(CONFIG_HYPERV) -TRACE_EVENT(hyperv_mmu_flush_tlb_others, +TRACE_EVENT(hyperv_mmu_flush_tlb_multi, TP_PROTO(const struct cpumask *cpus, const struct flush_tlb_info *info), TP_ARGS(cpus, info), diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 5e78e01ca3b4..38ea9dee2456 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -613,7 +613,7 @@ static int kvm_cpu_down_prepare(unsigned int cpu) } #endif -static void kvm_flush_tlb_others(const struct cpumask *cpumask, +static void kvm_flush_tlb_multi(const struct cpumask *cpumask, const struct flush_tlb_info *info) { u8 state; @@ -627,6 +627,11 @@ static void kvm_flush_tlb_others(const struct cpumask *cpumask, * queue flush_on_enter for pre-empted vCPUs */ for_each_cpu(cpu, flushmask) { + /* + * The local vCPU is never preempted, so we do not explicitly + * skip check for local vCPU - it will never be cleared from + * flushmask. + */ src = &per_cpu(steal_time, cpu); state = READ_ONCE(src->preempted); if ((state & KVM_VCPU_PREEMPTED)) { @@ -636,7 +641,7 @@ static void kvm_flush_tlb_others(const struct cpumask *cpumask, } } - native_flush_tlb_others(flushmask, info); + native_flush_tlb_multi(flushmask, info); } static void __init kvm_guest_init(void) @@ -654,7 +659,7 @@ static void __init kvm_guest_init(void) } if (pv_tlb_flush_supported()) { - pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others; + pv_ops.mmu.flush_tlb_multi = kvm_flush_tlb_multi; pv_ops.mmu.tlb_remove_table = tlb_remove_table; pr_info("KVM setup pv remote TLB flush\n"); } diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 07b6701a540a..78fcbd58716e 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -24,7 +24,7 @@ # define __flush_tlb_local native_flush_tlb_local # define __flush_tlb_global native_flush_tlb_global # define __flush_tlb_one_user(addr) native_flush_tlb_one_user(addr) -# define __flush_tlb_others(msk, info) native_flush_tlb_others(msk, info) +# define __flush_tlb_multi(msk, info) native_flush_tlb_multi(msk, info) #endif /* @@ -490,7 +490,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, /* * Even in lazy TLB mode, the CPU should stay set in the * mm_cpumask. The TLB shootdown code can figure out from - * from cpu_tlbstate.is_lazy whether or not to send an IPI. + * cpu_tlbstate.is_lazy whether or not to send an IPI. */ if (WARN_ON_ONCE(real_prev != &init_mm && !cpumask_test_cpu(cpu, mm_cpumask(next)))) @@ -697,7 +697,7 @@ static void flush_tlb_func(void *info) * garbage into our TLB. Since switching to init_mm is barely * slower than a minimal flush, just switch to init_mm. * - * This should be rare, with native_flush_tlb_others skipping + * This should be rare, with native_flush_tlb_multi() skipping * IPIs to lazy TLB mode CPUs. */ switch_mm_irqs_off(NULL, &init_mm, NULL); @@ -795,9 +795,14 @@ static bool tlb_is_not_lazy(int cpu) static DEFINE_PER_CPU(cpumask_t, flush_tlb_mask); -STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask, +STATIC_NOPV void native_flush_tlb_multi(const struct cpumask *cpumask, const struct flush_tlb_info *info) { + /* + * Do accounting and tracing. Note that there are (and have always been) + * cases in which a remote TLB flush will be traced, but eventually + * would not happen. + */ count_vm_tlb_event(NR_TLB_REMOTE_FLUSH); if (info->end == TLB_FLUSH_ALL) trace_tlb_flush(TLB_REMOTE_SEND_IPI, TLB_FLUSH_ALL); @@ -816,8 +821,8 @@ STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask, * doing a speculative memory access. */ if (info->freed_tables) { - smp_call_function_many(cpumask, flush_tlb_func, - (void *)info, 1); + on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true, + cpumask); } else { /* * Although we could have used on_each_cpu_cond_mask(), @@ -844,14 +849,15 @@ STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask, if (tlb_is_not_lazy(cpu)) __cpumask_set_cpu(cpu, cond_cpumask); } - smp_call_function_many(cond_cpumask, flush_tlb_func, (void *)info, 1); + on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true, + cpumask); } } -void flush_tlb_others(const struct cpumask *cpumask, +void flush_tlb_multi(const struct cpumask *cpumask, const struct flush_tlb_info *info) { - __flush_tlb_others(cpumask, info); + __flush_tlb_multi(cpumask, info); } /* @@ -931,16 +937,20 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, info = get_flush_tlb_info(mm, start, end, stride_shift, freed_tables, new_tlb_gen); - if (mm == this_cpu_read(cpu_tlbstate.loaded_mm)) { + /* + * flush_tlb_multi() is not optimized for the common case in which only + * a local TLB flush is needed. Optimize this use-case by calling + * flush_tlb_func_local() directly in this case. + */ + if (cpumask_any_but(mm_cpumask(mm), cpu) < nr_cpu_ids) { + flush_tlb_multi(mm_cpumask(mm), info); + } else if (mm == this_cpu_read(cpu_tlbstate.loaded_mm)) { lockdep_assert_irqs_enabled(); local_irq_disable(); flush_tlb_func(info); local_irq_enable(); } - if (cpumask_any_but(mm_cpumask(mm), cpu) < nr_cpu_ids) - flush_tlb_others(mm_cpumask(mm), info); - put_flush_tlb_info(); put_cpu(); } @@ -1151,17 +1161,20 @@ void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch) int cpu = get_cpu(); - info = get_flush_tlb_info(NULL, 0, TLB_FLUSH_ALL, 0, false, 0); - if (cpumask_test_cpu(cpu, &batch->cpumask)) { + /* + * flush_tlb_multi() is not optimized for the common case in which only + * a local TLB flush is needed. Optimize this use-case by calling + * flush_tlb_func_local() directly in this case. + */ + if (cpumask_any_but(&batch->cpumask, cpu) < nr_cpu_ids) { + flush_tlb_multi(&batch->cpumask, info); + } else if (cpumask_test_cpu(cpu, &batch->cpumask)) { lockdep_assert_irqs_enabled(); local_irq_disable(); flush_tlb_func(info); local_irq_enable(); } - if (cpumask_any_but(&batch->cpumask, cpu) < nr_cpu_ids) - flush_tlb_others(&batch->cpumask, info); - cpumask_clear(&batch->cpumask); put_flush_tlb_info(); diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index cf2ade864c30..09b95c0e876e 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -1247,8 +1247,8 @@ static void xen_flush_tlb_one_user(unsigned long addr) preempt_enable(); } -static void xen_flush_tlb_others(const struct cpumask *cpus, - const struct flush_tlb_info *info) +static void xen_flush_tlb_multi(const struct cpumask *cpus, + const struct flush_tlb_info *info) { struct { struct mmuext_op op; @@ -1258,7 +1258,7 @@ static void xen_flush_tlb_others(const struct cpumask *cpus, const size_t mc_entry_size = sizeof(args->op) + sizeof(args->mask[0]) * BITS_TO_LONGS(num_possible_cpus()); - trace_xen_mmu_flush_tlb_others(cpus, info->mm, info->start, info->end); + trace_xen_mmu_flush_tlb_multi(cpus, info->mm, info->start, info->end); if (cpumask_empty(cpus)) return; /* nothing to do */ @@ -1267,9 +1267,8 @@ static void xen_flush_tlb_others(const struct cpumask *cpus, args = mcs.args; args->op.arg2.vcpumask = to_cpumask(args->mask); - /* Remove us, and any offline CPUS. */ + /* Remove any offline CPUs */ cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask); - cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask)); args->op.cmd = MMUEXT_TLB_FLUSH_MULTI; if (info->end != TLB_FLUSH_ALL && @@ -2086,7 +2085,7 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = { .flush_tlb_user = xen_flush_tlb, .flush_tlb_kernel = xen_flush_tlb, .flush_tlb_one_user = xen_flush_tlb_one_user, - .flush_tlb_others = xen_flush_tlb_others, + .flush_tlb_multi = xen_flush_tlb_multi, .tlb_remove_table = tlb_remove_table, .pgd_alloc = xen_pgd_alloc, diff --git a/include/trace/events/xen.h b/include/trace/events/xen.h index 3b61b587e137..44a3f565264d 100644 --- a/include/trace/events/xen.h +++ b/include/trace/events/xen.h @@ -346,7 +346,7 @@ TRACE_EVENT(xen_mmu_flush_tlb_one_user, TP_printk("addr %lx", __entry->addr) ); -TRACE_EVENT(xen_mmu_flush_tlb_others, +TRACE_EVENT(xen_mmu_flush_tlb_multi, TP_PROTO(const struct cpumask *cpus, struct mm_struct *mm, unsigned long addr, unsigned long end), TP_ARGS(cpus, mm, addr, end),