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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B613CC433EF for ; Fri, 12 Nov 2021 12:31:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E8A661027 for ; Fri, 12 Nov 2021 12:31:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234998AbhKLMdu (ORCPT ); Fri, 12 Nov 2021 07:33:50 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:29155 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234960AbhKLMdr (ORCPT ); Fri, 12 Nov 2021 07:33:47 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636720256; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=W+s/ieSCtDDIuWMnJ5TfYJksHqeXpJbXZwE/vG2xMDc=; b=iQYYBcpRU2S7YDXWP/++Tr8OxW4pQOBBz7atgLx/2GYF+u+CRDjL3kXhf8H31N/c6n/U97 aX3+KYMv73w0G+s/S5VteV9uCpzsjLnNmeVJ9gma/L580ILsLK3W4t3zZStd2PcBHxjqSH tR9NUlnnneXS8bFuTTOaq8vWYiO4NQ0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-529-glWUNFTTNgWEyIMiZmkYTQ-1; Fri, 12 Nov 2021 07:30:53 -0500 X-MC-Unique: glWUNFTTNgWEyIMiZmkYTQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5E730802CB9; Fri, 12 Nov 2021 12:30:30 +0000 (UTC) Received: from fuller.cnet (ovpn-112-6.gru2.redhat.com [10.97.112.6]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 025891972E; Fri, 12 Nov 2021 12:30:30 +0000 (UTC) Received: by fuller.cnet (Postfix, from userid 1000) id 8A25C437FF94; Fri, 12 Nov 2021 09:29:05 -0300 (-03) Message-ID: <20211112122641.820409392@fedora.localdomain> User-Agent: quilt/0.66 Date: Fri, 12 Nov 2021 09:16:48 -0300 From: Marcelo Tosatti To: linux-kernel@vger.kernel.org Cc: Nitesh Lal , Nicolas Saenz Julienne , Frederic Weisbecker , Christoph Lameter , Juri Lelli , Peter Zijlstra , Alex Belits , Peter Xu , Thomas Gleixner , Daniel Bristot de Oliveira , Marcelo Tosatti Subject: [patch v6 06/10] task isolation: sync vmstats conditional on changes X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The logic to disable vmstat worker thread, when entering nohz full, does not cover all scenarios. For example, it is possible for the following to happen: References: <20211112121642.693790927@fedora.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Rather than syncing VM-stats on every return to userspace (or VM-entry), keep track of changes through a per-CPU bool. This improves performance when enabling task isolated for vcpu VMs. Signed-off-by: Marcelo Tosatti --- include/linux/vmstat.h | 13 ++++++++++++- mm/vmstat.c | 29 ++++++++++++++++++++++++++++- 2 files changed, 40 insertions(+), 2 deletions(-) Index: linux-2.6/include/linux/vmstat.h =================================================================== --- linux-2.6.orig/include/linux/vmstat.h +++ linux-2.6/include/linux/vmstat.h @@ -22,7 +22,18 @@ int sysctl_vm_numa_stat_handler(struct c #endif #ifdef CONFIG_SMP -void sync_vmstat(void); +DECLARE_PER_CPU_ALIGNED(bool, vmstat_dirty); + +extern struct static_key vmstat_sync_enabled; + +void __sync_vmstat(void); +static inline void sync_vmstat(void) +{ + if (static_key_false(&vmstat_sync_enabled)) + __sync_vmstat(); +} + +void init_sync_vmstat(void); #else static inline void sync_vmstat(void) { Index: linux-2.6/mm/vmstat.c =================================================================== --- linux-2.6.orig/mm/vmstat.c +++ linux-2.6/mm/vmstat.c @@ -306,6 +306,24 @@ void set_pgdat_percpu_threshold(pg_data_ } } +struct static_key vmstat_sync_enabled; +DEFINE_PER_CPU_ALIGNED(bool, vmstat_dirty); + +static inline void mark_vmstat_dirty(void) +{ + if (!static_key_false(&vmstat_sync_enabled)) + return; + + raw_cpu_write(vmstat_dirty, true); +} + +void init_sync_vmstat(void) +{ + raw_cpu_write(vmstat_dirty, true); +} + +EXPORT_SYMBOL_GPL(vmstat_dirty); + /* * For use when we know that interrupts are disabled, * or when we know that preemption is disabled and that @@ -338,6 +356,7 @@ void __mod_zone_page_state(struct zone * x = 0; } __this_cpu_write(*p, x); + mark_vmstat_dirty(); if (IS_ENABLED(CONFIG_PREEMPT_RT)) preempt_enable(); @@ -376,6 +395,7 @@ void __mod_node_page_state(struct pglist x = 0; } __this_cpu_write(*p, x); + mark_vmstat_dirty(); if (IS_ENABLED(CONFIG_PREEMPT_RT)) preempt_enable(); @@ -574,6 +594,7 @@ static inline void mod_zone_state(struct if (z) zone_page_state_add(z, zone, item); + mark_vmstat_dirty(); } void mod_zone_page_state(struct zone *zone, enum zone_stat_item item, @@ -642,6 +663,7 @@ static inline void mod_node_state(struct if (z) node_page_state_add(z, pgdat, item); + mark_vmstat_dirty(); } void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item, @@ -1082,6 +1104,7 @@ static void fill_contig_page_info(struct info->free_blocks_suitable += blocks << (order - suitable_order); } + mark_vmstat_dirty(); } /* @@ -1434,6 +1457,7 @@ static void walk_zones_in_node(struct se if (!nolock) spin_unlock_irqrestore(&zone->lock, flags); } + mark_vmstat_dirty(); } #endif @@ -1499,6 +1523,7 @@ static void pagetypeinfo_showfree_print( } seq_putc(m, '\n'); } + mark_vmstat_dirty(); } /* Print out the free pages at each order for each migatetype */ @@ -1917,6 +1942,7 @@ static void vmstat_update(struct work_st this_cpu_ptr(&vmstat_work), round_jiffies_relative(sysctl_stat_interval)); } + mark_vmstat_dirty(); } /* @@ -2003,13 +2029,14 @@ static void vmstat_shepherd(struct work_ round_jiffies_relative(sysctl_stat_interval)); } -void sync_vmstat(void) +void __sync_vmstat(void) { int cpu; cpu = get_cpu(); refresh_cpu_vm_stats(false); + raw_cpu_write(vmstat_dirty, false); put_cpu(); /*