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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 754CDC433FE for ; Thu, 27 Jan 2022 17:26:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244501AbiA0R0l (ORCPT ); Thu, 27 Jan 2022 12:26:41 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:38949 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241080AbiA0R0c (ORCPT ); Thu, 27 Jan 2022 12:26:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643304392; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=i6LIw9bQoy339JZLG9w/EEl7Pk8rtzd8+TGovQqiyK4=; b=QJCLjsMxeLbLPMww9AmF9DJm/T8lQrf26MY/Lm8mcGwZWOhXkuUVRCrTQZyBTptunig5w3 BiUXM85LEE1de7dGzFn7WBX4m0XtHK8USK+sNxOyy5SC2dIwj6nwlaFIuU9S8pbCUTdsak 6GSVVWNkuLT+5JlWkt0Kx3dr61t7hAo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-434-1Yjw8iQyOeCMCR9ipCEPWA-1; Thu, 27 Jan 2022 12:26:28 -0500 X-MC-Unique: 1Yjw8iQyOeCMCR9ipCEPWA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 739D78144ED; Thu, 27 Jan 2022 17:26:27 +0000 (UTC) Received: from fuller.cnet (ovpn-112-4.gru2.redhat.com [10.97.112.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 234D984D36; Thu, 27 Jan 2022 17:26:27 +0000 (UTC) Received: by fuller.cnet (Postfix, from userid 1000) id 99D8741692C7; Thu, 27 Jan 2022 14:26:05 -0300 (-03) Message-ID: <20220127172552.475356832@fuller.cnet> User-Agent: quilt/0.66 Date: Thu, 27 Jan 2022 14:23:25 -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 v9 06/10] task isolation: sync vmstats conditional on changes X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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: <20220127172319.428529308@fuller.cnet> 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 @@ -334,6 +334,24 @@ 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 @@ -366,6 +384,7 @@ 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(); @@ -404,6 +423,7 @@ 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(); @@ -602,6 +622,7 @@ 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, @@ -670,6 +691,7 @@ 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, @@ -1087,6 +1109,7 @@ static void fill_contig_page_info(struct info->free_blocks_suitable += blocks << (order - suitable_order); } + mark_vmstat_dirty(); } /* @@ -1443,6 +1466,7 @@ static void walk_zones_in_node(struct se if (!nolock) spin_unlock_irqrestore(&zone->lock, flags); } + mark_vmstat_dirty(); } #endif @@ -1512,6 +1536,7 @@ static void pagetypeinfo_showfree_print( } seq_putc(m, '\n'); } + mark_vmstat_dirty(); } /* Print out the free pages at each order for each migatetype */ @@ -1932,6 +1957,7 @@ static void vmstat_update(struct work_st this_cpu_ptr(&vmstat_work), round_jiffies_relative(sysctl_stat_interval)); } + mark_vmstat_dirty(); } /* @@ -2018,13 +2044,14 @@ 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(); /*