From nobody Sat Apr 11 08:26:27 2026 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 A46FEC7EE2F for ; Fri, 3 Mar 2023 20:01:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231569AbjCCUBk (ORCPT ); Fri, 3 Mar 2023 15:01:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231415AbjCCUBa (ORCPT ); Fri, 3 Mar 2023 15:01:30 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49C6160D67 for ; Fri, 3 Mar 2023 12:00:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677873636; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=gz8YmAWe77MPk6KLnyeDeBjg9daGz/JZkyszI8+E0yI=; b=hkoM2/FK5rbc/GMdqwiRHGUkwjLUE2vGu5xiWEqq2yiPDpUkoRASz2FUK41unhlxquqCfu MU5b1NwSNo+FGp6iI4kMJzVGnZv2YpLNEIVS7EGsnfArbADNng2vOjipcVtjP8L/TDbjqO +dYrG/4J4I9MhWPVEEOu/aRzQ6SVhBE= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-518-geIIwn8RNXmtnWL1QLi5hQ-1; Fri, 03 Mar 2023 15:00:32 -0500 X-MC-Unique: geIIwn8RNXmtnWL1QLi5hQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 97BA8280AA46; Fri, 3 Mar 2023 20:00:30 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2AE3B440D8; Fri, 3 Mar 2023 20:00:30 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 8A25240E00366; Fri, 3 Mar 2023 17:00:12 -0300 (-03) Message-ID: <20230303195908.774798959@redhat.com> User-Agent: quilt/0.67 Date: Fri, 03 Mar 2023 16:58:42 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Russell King , Huacai Chen , Heiko Carstens , x86@kernel.org, David Hildenbrand , Marcelo Tosatti Subject: [PATCH v3 01/11] mm/vmstat: remove remote node draining References: <20230303195841.310844446@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Draining of pages from the local pcp for a remote zone should not be necessary, since once the system is low on memory (or compaction on a zone is in effect), drain_all_pages should be called freeing any unused pcps. For reference, the original commit which introduces remote node draining is 4037d452202e34214e8a939fa5621b2b3bbb45b7. Acked-by: David Hildenbrand Signed-off-by: Marcelo Tosatti Index: linux-vmstat-remote/include/linux/mmzone.h =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/include/linux/mmzone.h +++ linux-vmstat-remote/include/linux/mmzone.h @@ -679,9 +679,6 @@ struct per_cpu_pages { int high; /* high watermark, emptying needed */ int batch; /* chunk size for buddy add/remove */ short free_factor; /* batch scaling factor during free */ -#ifdef CONFIG_NUMA - short expire; /* When 0, remote pagesets are drained */ -#endif =20 /* Lists of pages, one per migrate type stored on the pcp-lists */ struct list_head lists[NR_PCP_LISTS]; Index: linux-vmstat-remote/mm/vmstat.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/mm/vmstat.c +++ linux-vmstat-remote/mm/vmstat.c @@ -803,20 +803,16 @@ static int fold_diff(int *zone_diff, int * * The function returns the number of global counters updated. */ -static int refresh_cpu_vm_stats(bool do_pagesets) +static int refresh_cpu_vm_stats(void) { struct pglist_data *pgdat; struct zone *zone; int i; int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] =3D { 0, }; int global_node_diff[NR_VM_NODE_STAT_ITEMS] =3D { 0, }; - int changes =3D 0; =20 for_each_populated_zone(zone) { struct per_cpu_zonestat __percpu *pzstats =3D zone->per_cpu_zonestats; -#ifdef CONFIG_NUMA - struct per_cpu_pages __percpu *pcp =3D zone->per_cpu_pageset; -#endif =20 for (i =3D 0; i < NR_VM_ZONE_STAT_ITEMS; i++) { int v; @@ -826,44 +822,8 @@ static int refresh_cpu_vm_stats(bool do_ =20 atomic_long_add(v, &zone->vm_stat[i]); global_zone_diff[i] +=3D v; -#ifdef CONFIG_NUMA - /* 3 seconds idle till flush */ - __this_cpu_write(pcp->expire, 3); -#endif } } -#ifdef CONFIG_NUMA - - if (do_pagesets) { - cond_resched(); - /* - * Deal with draining the remote pageset of this - * processor - * - * Check if there are pages remaining in this pageset - * if not then there is nothing to expire. - */ - if (!__this_cpu_read(pcp->expire) || - !__this_cpu_read(pcp->count)) - continue; - - /* - * We never drain zones local to this processor. - */ - if (zone_to_nid(zone) =3D=3D numa_node_id()) { - __this_cpu_write(pcp->expire, 0); - continue; - } - - if (__this_cpu_dec_return(pcp->expire)) - continue; - - if (__this_cpu_read(pcp->count)) { - drain_zone_pages(zone, this_cpu_ptr(pcp)); - changes++; - } - } -#endif } =20 for_each_online_pgdat(pgdat) { @@ -880,8 +840,7 @@ static int refresh_cpu_vm_stats(bool do_ } } =20 - changes +=3D fold_diff(global_zone_diff, global_node_diff); - return changes; + return fold_diff(global_zone_diff, global_node_diff); } =20 /* @@ -1867,7 +1826,7 @@ int sysctl_stat_interval __read_mostly =3D #ifdef CONFIG_PROC_FS static void refresh_vm_stats(struct work_struct *work) { - refresh_cpu_vm_stats(true); + refresh_cpu_vm_stats(); } =20 int vmstat_refresh(struct ctl_table *table, int write, @@ -1877,6 +1836,8 @@ int vmstat_refresh(struct ctl_table *tab int err; int i; =20 + drain_all_pages(NULL); + /* * The regular update, every sysctl_stat_interval, may come later * than expected: leaving a significant amount in per_cpu buckets. @@ -1931,7 +1892,7 @@ int vmstat_refresh(struct ctl_table *tab =20 static void vmstat_update(struct work_struct *w) { - if (refresh_cpu_vm_stats(true)) { + if (refresh_cpu_vm_stats()) { /* * Counters were updated so we expect more updates * to occur in the future. Keep on running the @@ -1994,7 +1955,7 @@ void quiet_vmstat(void) * it would be too expensive from this path. * vmstat_shepherd will take care about that for us. */ - refresh_cpu_vm_stats(false); + refresh_cpu_vm_stats(); } =20 /* Index: linux-vmstat-remote/mm/page_alloc.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/mm/page_alloc.c +++ linux-vmstat-remote/mm/page_alloc.c @@ -3176,26 +3176,6 @@ static int rmqueue_bulk(struct zone *zon return allocated; } =20 -#ifdef CONFIG_NUMA -/* - * Called from the vmstat counter updater to drain pagesets of this - * currently executing processor on remote nodes after they have - * expired. - */ -void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp) -{ - int to_drain, batch; - - batch =3D READ_ONCE(pcp->batch); - to_drain =3D min(pcp->count, batch); - if (to_drain > 0) { - spin_lock(&pcp->lock); - free_pcppages_bulk(zone, to_drain, pcp, 0); - spin_unlock(&pcp->lock); - } -} -#endif - /* * Drain pcplists of the indicated processor and zone. */ From nobody Sat Apr 11 08:26:27 2026 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 AD2B2C64EC4 for ; Fri, 3 Mar 2023 20:02:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231707AbjCCUCI (ORCPT ); Fri, 3 Mar 2023 15:02:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231430AbjCCUBi (ORCPT ); Fri, 3 Mar 2023 15:01:38 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4547D618A9 for ; Fri, 3 Mar 2023 12:00:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677873641; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=iUvNynje4NLXuVViJqGVXz34mfwfY1r+EmC29iXiBlQ=; b=IJykAkQpJjDAvTGGbqOdK597/YxkmwAJj9g7Mn5lr6TCTUhbOSqes5CwZzxVXf2MnY2vv3 15XUraUt3xA28u/zWpVvLbxfZJORXuA6Bhe611gQWH7cjKXQtJULN1RUAUm9ixV9UJXnLe IDeh3k0kopkuy/A72OeBxERYgs4d9F0= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-516-PxqYS3KjPXirwMt8cwawRQ-1; Fri, 03 Mar 2023 15:00:30 -0500 X-MC-Unique: PxqYS3KjPXirwMt8cwawRQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 53E9A85C70B; Fri, 3 Mar 2023 20:00:30 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1E0FB40C6EC4; Fri, 3 Mar 2023 20:00:30 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 8C9F04291962B; Fri, 3 Mar 2023 17:00:12 -0300 (-03) Message-ID: <20230303195908.800742864@redhat.com> User-Agent: quilt/0.67 Date: Fri, 03 Mar 2023 16:58:43 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Russell King , Huacai Chen , Heiko Carstens , x86@kernel.org, Marcelo Tosatti Subject: [PATCH v3 02/11] this_cpu_cmpxchg: ARM64: switch this_cpu_cmpxchg to locked, add _local function References: <20230303195841.310844446@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Goal is to have vmstat_shepherd to transfer from per-CPU counters to global counters remotely. For this,=20 an atomic this_cpu_cmpxchg is necessary. Following the kernel convention for cmpxchg/cmpxchg_local, change ARM's this_cpu_cmpxchg_ helpers to be atomic, and add this_cpu_cmpxchg_local_ helpers which are not atomic. Signed-off-by: Marcelo Tosatti Index: linux-vmstat-remote/arch/arm64/include/asm/percpu.h =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/arch/arm64/include/asm/percpu.h +++ linux-vmstat-remote/arch/arm64/include/asm/percpu.h @@ -232,13 +232,23 @@ PERCPU_RET_OP(add, add, ldadd) _pcp_protect_return(xchg_relaxed, pcp, val) =20 #define this_cpu_cmpxchg_1(pcp, o, n) \ - _pcp_protect_return(cmpxchg_relaxed, pcp, o, n) + _pcp_protect_return(cmpxchg, pcp, o, n) #define this_cpu_cmpxchg_2(pcp, o, n) \ - _pcp_protect_return(cmpxchg_relaxed, pcp, o, n) + _pcp_protect_return(cmpxchg, pcp, o, n) #define this_cpu_cmpxchg_4(pcp, o, n) \ - _pcp_protect_return(cmpxchg_relaxed, pcp, o, n) + _pcp_protect_return(cmpxchg, pcp, o, n) #define this_cpu_cmpxchg_8(pcp, o, n) \ + _pcp_protect_return(cmpxchg, pcp, o, n) + +#define this_cpu_cmpxchg_local_1(pcp, o, n) \ _pcp_protect_return(cmpxchg_relaxed, pcp, o, n) +#define this_cpu_cmpxchg_local_2(pcp, o, n) \ + _pcp_protect_return(cmpxchg_relaxed, pcp, o, n) +#define this_cpu_cmpxchg_local_4(pcp, o, n) \ + _pcp_protect_return(cmpxchg_relaxed, pcp, o, n) +#define this_cpu_cmpxchg_local_8(pcp, o, n) \ + _pcp_protect_return(cmpxchg_relaxed, pcp, o, n) + =20 #ifdef __KVM_NVHE_HYPERVISOR__ extern unsigned long __hyp_per_cpu_offset(unsigned int cpu); From nobody Sat Apr 11 08:26:27 2026 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 454E5C64EC4 for ; Fri, 3 Mar 2023 20:01:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231603AbjCCUBq (ORCPT ); Fri, 3 Mar 2023 15:01:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56210 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231441AbjCCUBb (ORCPT ); Fri, 3 Mar 2023 15:01:31 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AEB3161899 for ; Fri, 3 Mar 2023 12:00:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677873635; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=1qMXUw9dsgBVhjNMR0OfieQvkRg7GOetq5N/8/ayAmg=; b=ALDWz8iLtjE1LyHyXNlv1qaPWqT0rlFdDI11quukl0i7fOsDhUV9Z+N0igM9csF63U9G+e pk7TxD5vG05prrRT1mCEZ2sK1cfMh/ShQazAiWvwS4nWd2fk16/7D5v3gpw3ABJsMjEh54 QJjp7lpDqoelogne0iHO/DObMwYSFFo= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-516-fgnJlgi-OousMj4BXlHHWQ-1; Fri, 03 Mar 2023 15:00:31 -0500 X-MC-Unique: fgnJlgi-OousMj4BXlHHWQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6572338123AE; Fri, 3 Mar 2023 20:00:30 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 377734010E86; Fri, 3 Mar 2023 20:00:30 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 8FD6A4291962C; Fri, 3 Mar 2023 17:00:12 -0300 (-03) Message-ID: <20230303195908.826802488@redhat.com> User-Agent: quilt/0.67 Date: Fri, 03 Mar 2023 16:58:44 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Russell King , Huacai Chen , Heiko Carstens , x86@kernel.org, Marcelo Tosatti Subject: [PATCH v3 03/11] this_cpu_cmpxchg: loongarch: switch this_cpu_cmpxchg to locked, add _local function References: <20230303195841.310844446@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Goal is to have vmstat_shepherd to transfer from per-CPU counters to global counters remotely. For this, an atomic this_cpu_cmpxchg is necessary. Following the kernel convention for cmpxchg/cmpxchg_local, add this_cpu_cmpxchg_local helpers to Loongarch. Signed-off-by: Marcelo Tosatti Index: linux-vmstat-remote/arch/loongarch/include/asm/percpu.h =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/arch/loongarch/include/asm/percpu.h +++ linux-vmstat-remote/arch/loongarch/include/asm/percpu.h @@ -150,6 +150,16 @@ static inline unsigned long __percpu_xch } =20 /* this_cpu_cmpxchg */ +#define _protect_cmpxchg(pcp, o, n) \ +({ \ + typeof(*raw_cpu_ptr(&(pcp))) __ret; \ + preempt_disable_notrace(); \ + __ret =3D cmpxchg(raw_cpu_ptr(&(pcp)), o, n); \ + preempt_enable_notrace(); \ + __ret; \ +}) + +/* this_cpu_cmpxchg_local */ #define _protect_cmpxchg_local(pcp, o, n) \ ({ \ typeof(*raw_cpu_ptr(&(pcp))) __ret; \ @@ -222,10 +232,15 @@ do { \ #define this_cpu_xchg_4(pcp, val) _percpu_xchg(pcp, val) #define this_cpu_xchg_8(pcp, val) _percpu_xchg(pcp, val) =20 -#define this_cpu_cmpxchg_1(ptr, o, n) _protect_cmpxchg_local(ptr, o, n) -#define this_cpu_cmpxchg_2(ptr, o, n) _protect_cmpxchg_local(ptr, o, n) -#define this_cpu_cmpxchg_4(ptr, o, n) _protect_cmpxchg_local(ptr, o, n) -#define this_cpu_cmpxchg_8(ptr, o, n) _protect_cmpxchg_local(ptr, o, n) +#define this_cpu_cmpxchg_local_1(ptr, o, n) _protect_cmpxchg_local(ptr, o,= n) +#define this_cpu_cmpxchg_local_2(ptr, o, n) _protect_cmpxchg_local(ptr, o,= n) +#define this_cpu_cmpxchg_local_4(ptr, o, n) _protect_cmpxchg_local(ptr, o,= n) +#define this_cpu_cmpxchg_local_8(ptr, o, n) _protect_cmpxchg_local(ptr, o,= n) + +#define this_cpu_cmpxchg_1(ptr, o, n) _protect_cmpxchg(ptr, o, n) +#define this_cpu_cmpxchg_2(ptr, o, n) _protect_cmpxchg(ptr, o, n) +#define this_cpu_cmpxchg_4(ptr, o, n) _protect_cmpxchg(ptr, o, n) +#define this_cpu_cmpxchg_8(ptr, o, n) _protect_cmpxchg(ptr, o, n) =20 #include From nobody Sat Apr 11 08:26:27 2026 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 3FA82C64EC4 for ; Fri, 3 Mar 2023 20:02:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231673AbjCCUCC (ORCPT ); Fri, 3 Mar 2023 15:02:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231131AbjCCUBg (ORCPT ); Fri, 3 Mar 2023 15:01:36 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 88BF9618A3 for ; Fri, 3 Mar 2023 12:00:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677873638; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=FePX2+VFBr01iZwaVbBM1HjdLAtX/eNoAgkcl35m848=; b=KSY/UGmkOICZBjC1TXM3cZ76COuXc0x1s0sjcUgNNlufPvWQuarqGtF9vE0JnCjWjaqIje z5LvYvd87v2afIvtdRPIxSHGu5/ujRvryv6fCdM4yvc0VsEveXX1Q7ezWdIApa9sdCdBZA xNdC+lSyJubQz0tEZAyBv9QB+WSZiMg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-212-OPuKcFE6ON6wpaC72tuhoQ-1; Fri, 03 Mar 2023 15:00:33 -0500 X-MC-Unique: OPuKcFE6ON6wpaC72tuhoQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5A063185A7A4; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2D93D40CF8EF; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 94CB94291962D; Fri, 3 Mar 2023 17:00:12 -0300 (-03) Message-ID: <20230303195908.851997547@redhat.com> User-Agent: quilt/0.67 Date: Fri, 03 Mar 2023 16:58:45 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Russell King , Huacai Chen , Heiko Carstens , x86@kernel.org, Marcelo Tosatti Subject: [PATCH v3 04/11] this_cpu_cmpxchg: S390: switch this_cpu_cmpxchg to locked, add _local function References: <20230303195841.310844446@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Goal is to have vmstat_shepherd to transfer from per-CPU counters to global counters remotely. For this, an atomic this_cpu_cmpxchg is necessary. Following the kernel convention for cmpxchg/cmpxchg_local, add S390's this_cpu_cmpxchg_local. Signed-off-by: Marcelo Tosatti Index: linux-vmstat-remote/arch/s390/include/asm/percpu.h =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/arch/s390/include/asm/percpu.h +++ linux-vmstat-remote/arch/s390/include/asm/percpu.h @@ -148,6 +148,11 @@ #define this_cpu_cmpxchg_4(pcp, oval, nval) arch_this_cpu_cmpxchg(pcp, ova= l, nval) #define this_cpu_cmpxchg_8(pcp, oval, nval) arch_this_cpu_cmpxchg(pcp, ova= l, nval) =20 +#define this_cpu_cmpxchg_local_1(pcp, oval, nval) arch_this_cpu_cmpxchg(pc= p, oval, nval) +#define this_cpu_cmpxchg_local_2(pcp, oval, nval) arch_this_cpu_cmpxchg(pc= p, oval, nval) +#define this_cpu_cmpxchg_local_4(pcp, oval, nval) arch_this_cpu_cmpxchg(pc= p, oval, nval) +#define this_cpu_cmpxchg_local_8(pcp, oval, nval) arch_this_cpu_cmpxchg(pc= p, oval, nval) + #define arch_this_cpu_xchg(pcp, nval) \ ({ \ typeof(pcp) *ptr__; \ From nobody Sat Apr 11 08:26:27 2026 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 992DFC7EE2F for ; Fri, 3 Mar 2023 20:02:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231668AbjCCUCL (ORCPT ); Fri, 3 Mar 2023 15:02:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231557AbjCCUBi (ORCPT ); Fri, 3 Mar 2023 15:01:38 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6477D61890 for ; Fri, 3 Mar 2023 12:00:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677873635; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=hjd5gtUB1FFqfcJWUv9qrW5kcd1bszAAtI+X6kwFBXk=; b=X+m+D57bpiaqCWxNYc9f0RV+z7ZzRDFMqm/PR+j24jhR/NBnjjioJk+vzlTxWs2cl1NmNd jor7WW+rLa9BeuI4NcujmTiDVMexYxgf8kf+dTJGEzZ1IPgAP03JvF03RS1SAyV0YpSmK3 /aV//LklbOuLZKFFAE1NN1JS6E1vOeg= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-101-cMDpLZCKMwyZ6cNzNBnl9Q-1; Fri, 03 Mar 2023 15:00:33 -0500 X-MC-Unique: cMDpLZCKMwyZ6cNzNBnl9Q-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5BD4F280AA49; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 093FF40BC781; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 986474291962E; Fri, 3 Mar 2023 17:00:12 -0300 (-03) Message-ID: <20230303195908.877083312@redhat.com> User-Agent: quilt/0.67 Date: Fri, 03 Mar 2023 16:58:46 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Russell King , Huacai Chen , Heiko Carstens , x86@kernel.org, Marcelo Tosatti Subject: [PATCH v3 05/11] this_cpu_cmpxchg: x86: switch this_cpu_cmpxchg to locked, add _local function References: <20230303195841.310844446@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Goal is to have vmstat_shepherd to transfer from per-CPU counters to global counters remotely. For this, an atomic this_cpu_cmpxchg is necessary. Following the kernel convention for cmpxchg/cmpxchg_local, change x86's this_cpu_cmpxchg_ helpers to be atomic. and add this_cpu_cmpxchg_local_ helpers which are not atomic. Signed-off-by: Marcelo Tosatti Index: linux-vmstat-remote/arch/x86/include/asm/percpu.h =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/arch/x86/include/asm/percpu.h +++ linux-vmstat-remote/arch/x86/include/asm/percpu.h @@ -197,11 +197,11 @@ do { \ * cmpxchg has no such implied lock semantics as a result it is much * more efficient for cpu local operations. */ -#define percpu_cmpxchg_op(size, qual, _var, _oval, _nval) \ +#define percpu_cmpxchg_op(size, qual, _var, _oval, _nval, lockp) \ ({ \ __pcpu_type_##size pco_old__ =3D __pcpu_cast_##size(_oval); \ __pcpu_type_##size pco_new__ =3D __pcpu_cast_##size(_nval); \ - asm qual (__pcpu_op2_##size("cmpxchg", "%[nval]", \ + asm qual (__pcpu_op2_##size(lockp "cmpxchg", "%[nval]", \ __percpu_arg([var])) \ : [oval] "+a" (pco_old__), \ [var] "+m" (_var) \ @@ -279,16 +279,20 @@ do { \ #define raw_cpu_add_return_1(pcp, val) percpu_add_return_op(1, , pcp, val) #define raw_cpu_add_return_2(pcp, val) percpu_add_return_op(2, , pcp, val) #define raw_cpu_add_return_4(pcp, val) percpu_add_return_op(4, , pcp, val) -#define raw_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(1, , pcp, ova= l, nval) -#define raw_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(2, , pcp, ova= l, nval) -#define raw_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(4, , pcp, ova= l, nval) +#define raw_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(1, , pcp, ova= l, nval, "") +#define raw_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(2, , pcp, ova= l, nval, "") +#define raw_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(4, , pcp, ova= l, nval, "") =20 #define this_cpu_add_return_1(pcp, val) percpu_add_return_op(1, volatile,= pcp, val) #define this_cpu_add_return_2(pcp, val) percpu_add_return_op(2, volatile,= pcp, val) #define this_cpu_add_return_4(pcp, val) percpu_add_return_op(4, volatile,= pcp, val) -#define this_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(1, volatile,= pcp, oval, nval) -#define this_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(2, volatile,= pcp, oval, nval) -#define this_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(4, volatile,= pcp, oval, nval) +#define this_cpu_cmpxchg_local_1(pcp, oval, nval) percpu_cmpxchg_op(1, vol= atile, pcp, oval, nval, "") +#define this_cpu_cmpxchg_local_2(pcp, oval, nval) percpu_cmpxchg_op(2, vol= atile, pcp, oval, nval, "") +#define this_cpu_cmpxchg_local_4(pcp, oval, nval) percpu_cmpxchg_op(4, vol= atile, pcp, oval, nval, "") + +#define this_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(1, volatile,= pcp, oval, nval, LOCK_PREFIX) +#define this_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(2, volatile,= pcp, oval, nval, LOCK_PREFIX) +#define this_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(4, volatile,= pcp, oval, nval, LOCK_PREFIX) =20 #ifdef CONFIG_X86_CMPXCHG64 #define percpu_cmpxchg8b_double(pcp1, pcp2, o1, o2, n1, n2) \ @@ -319,16 +323,17 @@ do { \ #define raw_cpu_or_8(pcp, val) percpu_to_op(8, , "or", (pcp), val) #define raw_cpu_add_return_8(pcp, val) percpu_add_return_op(8, , pcp, val) #define raw_cpu_xchg_8(pcp, nval) raw_percpu_xchg_op(pcp, nval) -#define raw_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(8, , pcp, ova= l, nval) +#define raw_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(8, , pcp, ova= l, nval, "") =20 -#define this_cpu_read_8(pcp) percpu_from_op(8, volatile, "mov", pcp) -#define this_cpu_write_8(pcp, val) percpu_to_op(8, volatile, "mov", (pcp)= , val) -#define this_cpu_add_8(pcp, val) percpu_add_op(8, volatile, (pcp), val) -#define this_cpu_and_8(pcp, val) percpu_to_op(8, volatile, "and", (pcp), = val) -#define this_cpu_or_8(pcp, val) percpu_to_op(8, volatile, "or", (pcp), v= al) -#define this_cpu_add_return_8(pcp, val) percpu_add_return_op(8, volatile,= pcp, val) -#define this_cpu_xchg_8(pcp, nval) percpu_xchg_op(8, volatile, pcp, nval) -#define this_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(8, volatile,= pcp, oval, nval) +#define this_cpu_read_8(pcp) percpu_from_op(8, volatile, "mov", pcp) +#define this_cpu_write_8(pcp, val) percpu_to_op(8, volatile, "mov", (pcp= ), val) +#define this_cpu_add_8(pcp, val) percpu_add_op(8, volatile, (pcp), val) +#define this_cpu_and_8(pcp, val) percpu_to_op(8, volatile, "and", (pcp),= val) +#define this_cpu_or_8(pcp, val) percpu_to_op(8, volatile, "or", (pcp), = val) +#define this_cpu_add_return_8(pcp, val) percpu_add_return_op(8, volatile= , pcp, val) +#define this_cpu_xchg_8(pcp, nval) percpu_xchg_op(8, volatile, pcp, nval) +#define this_cpu_cmpxchg_local_8(pcp, oval, nval) percpu_cmpxchg_op(8, vol= atile, pcp, oval, nval, "") +#define this_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(8, volatile= , pcp, oval, nval, LOCK_PREFIX) =20 /* * Pretty complex macro to generate cmpxchg16 instruction. The instruction From nobody Sat Apr 11 08:26:27 2026 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 CC163C64EC4 for ; Fri, 3 Mar 2023 20:01:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231243AbjCCUBh (ORCPT ); Fri, 3 Mar 2023 15:01:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231430AbjCCUBa (ORCPT ); Fri, 3 Mar 2023 15:01:30 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF0FB6189F for ; Fri, 3 Mar 2023 12:00:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677873635; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=X5A6sr5GdS/CRp9e0AjLg+A82o3GBDzuPA8yAWqGcJk=; b=CP779k+XU5a/xL30gNTAPQ9g8CiFpc1hCVxIFVm85/qIxrI8bzGqPEAKU5iJ9yOzJLapCU J8gqL3IefsN4D7KP6J5TGJffa8VIg/g0YcYt96ZXe82dSIQDDIt4gKben1ORqq8FKs1uR3 N9dWAPvtIDpWvQ8FjIJQBrrEIFd6JOs= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-70-TL7B6PkrOIq9tqOikCZwhA-1; Fri, 03 Mar 2023 15:00:32 -0500 X-MC-Unique: TL7B6PkrOIq9tqOikCZwhA-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 403DE803491; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 14CB4492B00; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 9DD5C4291962F; Fri, 3 Mar 2023 17:00:12 -0300 (-03) Message-ID: <20230303195908.901973993@redhat.com> User-Agent: quilt/0.67 Date: Fri, 03 Mar 2023 16:58:47 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Russell King , Huacai Chen , Heiko Carstens , x86@kernel.org, Marcelo Tosatti Subject: [PATCH v3 06/11] add this_cpu_cmpxchg_local and asm-generic definitions References: <20230303195841.310844446@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Goal is to have vmstat_shepherd to transfer from per-CPU counters to global counters remotely. For this, an atomic this_cpu_cmpxchg is necessary. Add this_cpu_cmpxchg_local_ helpers to asm-generic/percpu.h. Signed-off-by: Marcelo Tosatti Index: linux-vmstat-remote/include/asm-generic/percpu.h =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/include/asm-generic/percpu.h +++ linux-vmstat-remote/include/asm-generic/percpu.h @@ -424,6 +424,23 @@ do { \ this_cpu_generic_cmpxchg(pcp, oval, nval) #endif =20 +#ifndef this_cpu_cmpxchg_local_1 +#define this_cpu_cmpxchg_local_1(pcp, oval, nval) \ + this_cpu_generic_cmpxchg(pcp, oval, nval) +#endif +#ifndef this_cpu_cmpxchg_local_2 +#define this_cpu_cmpxchg_local_2(pcp, oval, nval) \ + this_cpu_generic_cmpxchg(pcp, oval, nval) +#endif +#ifndef this_cpu_cmpxchg_local_4 +#define this_cpu_cmpxchg_local_4(pcp, oval, nval) \ + this_cpu_generic_cmpxchg(pcp, oval, nval) +#endif +#ifndef this_cpu_cmpxchg_local_8 +#define this_cpu_cmpxchg_local_8(pcp, oval, nval) \ + this_cpu_generic_cmpxchg(pcp, oval, nval) +#endif + #ifndef this_cpu_cmpxchg_double_1 #define this_cpu_cmpxchg_double_1(pcp1, pcp2, oval1, oval2, nval1, nval2) \ this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) Index: linux-vmstat-remote/include/linux/percpu-defs.h =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/include/linux/percpu-defs.h +++ linux-vmstat-remote/include/linux/percpu-defs.h @@ -513,6 +513,8 @@ do { \ #define this_cpu_xchg(pcp, nval) __pcpu_size_call_return2(this_cpu_xchg_, = pcp, nval) #define this_cpu_cmpxchg(pcp, oval, nval) \ __pcpu_size_call_return2(this_cpu_cmpxchg_, pcp, oval, nval) +#define this_cpu_cmpxchg_local(pcp, oval, nval) \ + __pcpu_size_call_return2(this_cpu_cmpxchg_local_, pcp, oval, nval) #define this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \ __pcpu_double_call_return_bool(this_cpu_cmpxchg_double_, pcp1, pcp2, oval= 1, oval2, nval1, nval2) From nobody Sat Apr 11 08:26:27 2026 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 81DC6C64EC4 for ; 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Fri, 03 Mar 2023 15:00:32 -0500 X-MC-Unique: XHhHsPN-OM-HKLtx0grcWA-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3AA4F80D0F1; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0612A492C14; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id A344242919630; Fri, 3 Mar 2023 17:00:12 -0300 (-03) Message-ID: <20230303195908.926950608@redhat.com> User-Agent: quilt/0.67 Date: Fri, 03 Mar 2023 16:58:48 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Russell King , Huacai Chen , Heiko Carstens , x86@kernel.org, Peter Xu , Marcelo Tosatti Subject: [PATCH v3 07/11] convert this_cpu_cmpxchg users to this_cpu_cmpxchg_local References: <20230303195841.310844446@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" this_cpu_cmpxchg was modified to atomic version, which=20 can be more costly than non-atomic version. Switch users of this_cpu_cmpxchg to this_cpu_cmpxchg_local (which preserves pre-non-atomic this_cpu_cmpxchg behaviour). Acked-by: Peter Xu Signed-off-by: Marcelo Tosatti Index: linux-vmstat-remote/kernel/fork.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/kernel/fork.c +++ linux-vmstat-remote/kernel/fork.c @@ -203,7 +203,7 @@ static bool try_release_thread_stack_to_ unsigned int i; =20 for (i =3D 0; i < NR_CACHED_STACKS; i++) { - if (this_cpu_cmpxchg(cached_stacks[i], NULL, vm) !=3D NULL) + if (this_cpu_cmpxchg_local(cached_stacks[i], NULL, vm) !=3D NULL) continue; return true; } Index: linux-vmstat-remote/kernel/scs.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/kernel/scs.c +++ linux-vmstat-remote/kernel/scs.c @@ -83,7 +83,7 @@ void scs_free(void *s) */ =20 for (i =3D 0; i < NR_CACHED_SCS; i++) - if (this_cpu_cmpxchg(scs_cache[i], 0, s) =3D=3D NULL) + if (this_cpu_cmpxchg_local(scs_cache[i], 0, s) =3D=3D NULL) return; =20 kasan_unpoison_vmalloc(s, SCS_SIZE, KASAN_VMALLOC_PROT_NORMAL); From nobody Sat Apr 11 08:26:27 2026 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 65EA0C7EE32 for ; Fri, 3 Mar 2023 20:01:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231613AbjCCUBw (ORCPT ); Fri, 3 Mar 2023 15:01:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56200 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231444AbjCCUBb (ORCPT ); Fri, 3 Mar 2023 15:01:31 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 92D4360D44 for ; Fri, 3 Mar 2023 12:00:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677873634; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=kck/KScqtu56KKjBhC7jhwkN1m2f1dyAwfBXk4OMNDU=; b=d0c2ybKTvtTwEHwxjxceyafvGK812cNnQNL63gwfmUf3jokQiNC0Y/jG1O7XJw7t62me7O 3FvoXrfYUCA+bNKNFuNbnOTKmppYc0YHE7ze99h9OmIQtBThNQaD0JE3pQ8xPqxmx5dJyf 5Kr/oaRkI20wN02DbFEnBR5Pe+EtaJs= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-634-3UIEbQqAPI-iF1Ofjgcasg-1; Fri, 03 Mar 2023 15:00:33 -0500 X-MC-Unique: 3UIEbQqAPI-iF1Ofjgcasg-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 82FB2858F09; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 31152492C18; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id A7AFB42919631; Fri, 3 Mar 2023 17:00:12 -0300 (-03) Message-ID: <20230303195908.952010050@redhat.com> User-Agent: quilt/0.67 Date: Fri, 03 Mar 2023 16:58:49 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Russell King , Huacai Chen , Heiko Carstens , x86@kernel.org, Marcelo Tosatti Subject: [PATCH v3 08/11] mm/vmstat: switch counter modification to cmpxchg References: <20230303195841.310844446@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" In preparation for switching vmstat shepherd to flush per-CPU counters remotely, switch the __{mod,inc,dec} functions that modify the counters to use cmpxchg. To facilitate reviewing, functions are ordered in the text file, as: __{mod,inc,dec}_{zone,node}_page_state #ifdef CONFIG_HAVE_CMPXCHG_LOCAL {mod,inc,dec}_{zone,node}_page_state #else {mod,inc,dec}_{zone,node}_page_state #endif This patch defines the __ versions for the CONFIG_HAVE_CMPXCHG_LOCAL case to be their non-"__" counterparts: #ifdef CONFIG_HAVE_CMPXCHG_LOCAL {mod,inc,dec}_{zone,node}_page_state __{mod,inc,dec}_{zone,node}_page_state =3D {mod,inc,dec}_{zone,node}_page_s= tate #else {mod,inc,dec}_{zone,node}_page_state __{mod,inc,dec}_{zone,node}_page_state #endif To test the performance difference, a page allocator microbenchmark: https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/mm/benc= h/page_bench01.c=20 with loops=3D1000000 was used, on Intel Core i7-11850H @ 2.50GHz. For the single_page_alloc_free test, which does /** Loop to measure **/ for (i =3D 0; i < rec->loops; i++) { my_page =3D alloc_page(gfp_mask); if (unlikely(my_page =3D=3D NULL)) return 0; __free_page(my_page); } Unit is cycles. Vanilla Patched Diff 115.25 117 1.4% Signed-off-by: Marcelo Tosatti Index: linux-vmstat-remote/mm/vmstat.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/mm/vmstat.c +++ linux-vmstat-remote/mm/vmstat.c @@ -334,6 +334,188 @@ void set_pgdat_percpu_threshold(pg_data_ } } =20 +#ifdef CONFIG_HAVE_CMPXCHG_LOCAL +/* + * If we have cmpxchg_local support then we do not need to incur the overh= ead + * that comes with local_irq_save/restore if we use this_cpu_cmpxchg. + * + * mod_state() modifies the zone counter state through atomic per cpu + * operations. + * + * Overstep mode specifies how overstep should handled: + * 0 No overstepping + * 1 Overstepping half of threshold + * -1 Overstepping minus half of threshold + */ +static inline void mod_zone_state(struct zone *zone, enum zone_stat_item i= tem, + long delta, int overstep_mode) +{ + struct per_cpu_zonestat __percpu *pcp =3D zone->per_cpu_zonestats; + s8 __percpu *p =3D pcp->vm_stat_diff + item; + long o, n, t, z; + + do { + z =3D 0; /* overflow to zone counters */ + + /* + * The fetching of the stat_threshold is racy. We may apply + * a counter threshold to the wrong the cpu if we get + * rescheduled while executing here. However, the next + * counter update will apply the threshold again and + * therefore bring the counter under the threshold again. + * + * Most of the time the thresholds are the same anyways + * for all cpus in a zone. + */ + t =3D this_cpu_read(pcp->stat_threshold); + + o =3D this_cpu_read(*p); + n =3D delta + o; + + if (abs(n) > t) { + int os =3D overstep_mode * (t >> 1); + + /* Overflow must be added to zone counters */ + z =3D n + os; + n =3D -os; + } + } while (this_cpu_cmpxchg(*p, o, n) !=3D o); + + if (z) + zone_page_state_add(z, zone, item); +} + +void mod_zone_page_state(struct zone *zone, enum zone_stat_item item, + long delta) +{ + mod_zone_state(zone, item, delta, 0); +} +EXPORT_SYMBOL(mod_zone_page_state); + +void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item, + long delta) +{ + mod_zone_state(zone, item, delta, 0); +} +EXPORT_SYMBOL(__mod_zone_page_state); + +void inc_zone_page_state(struct page *page, enum zone_stat_item item) +{ + mod_zone_state(page_zone(page), item, 1, 1); +} +EXPORT_SYMBOL(inc_zone_page_state); + +void __inc_zone_page_state(struct page *page, enum zone_stat_item item) +{ + mod_zone_state(page_zone(page), item, 1, 1); +} +EXPORT_SYMBOL(__inc_zone_page_state); + +void dec_zone_page_state(struct page *page, enum zone_stat_item item) +{ + mod_zone_state(page_zone(page), item, -1, -1); +} +EXPORT_SYMBOL(dec_zone_page_state); + +void __dec_zone_page_state(struct page *page, enum zone_stat_item item) +{ + mod_zone_state(page_zone(page), item, -1, -1); +} +EXPORT_SYMBOL(__dec_zone_page_state); + +static inline void mod_node_state(struct pglist_data *pgdat, + enum node_stat_item item, + int delta, int overstep_mode) +{ + struct per_cpu_nodestat __percpu *pcp =3D pgdat->per_cpu_nodestats; + s8 __percpu *p =3D pcp->vm_node_stat_diff + item; + long o, n, t, z; + + if (vmstat_item_in_bytes(item)) { + /* + * Only cgroups use subpage accounting right now; at + * the global level, these items still change in + * multiples of whole pages. Store them as pages + * internally to keep the per-cpu counters compact. + */ + VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1)); + delta >>=3D PAGE_SHIFT; + } + + do { + z =3D 0; /* overflow to node counters */ + + /* + * The fetching of the stat_threshold is racy. We may apply + * a counter threshold to the wrong the cpu if we get + * rescheduled while executing here. However, the next + * counter update will apply the threshold again and + * therefore bring the counter under the threshold again. + * + * Most of the time the thresholds are the same anyways + * for all cpus in a node. + */ + t =3D this_cpu_read(pcp->stat_threshold); + + o =3D this_cpu_read(*p); + n =3D delta + o; + + if (abs(n) > t) { + int os =3D overstep_mode * (t >> 1); + + /* Overflow must be added to node counters */ + z =3D n + os; + n =3D -os; + } + } while (this_cpu_cmpxchg(*p, o, n) !=3D o); + + if (z) + node_page_state_add(z, pgdat, item); +} + +void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item it= em, + long delta) +{ + mod_node_state(pgdat, item, delta, 0); +} +EXPORT_SYMBOL(mod_node_page_state); + +void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item = item, + long delta) +{ + mod_node_state(pgdat, item, delta, 0); +} +EXPORT_SYMBOL(__mod_node_page_state); + +void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item) +{ + mod_node_state(pgdat, item, 1, 1); +} + +void inc_node_page_state(struct page *page, enum node_stat_item item) +{ + mod_node_state(page_pgdat(page), item, 1, 1); +} +EXPORT_SYMBOL(inc_node_page_state); + +void __inc_node_page_state(struct page *page, enum node_stat_item item) +{ + mod_node_state(page_pgdat(page), item, 1, 1); +} +EXPORT_SYMBOL(__inc_node_page_state); + +void dec_node_page_state(struct page *page, enum node_stat_item item) +{ + mod_node_state(page_pgdat(page), item, -1, -1); +} +EXPORT_SYMBOL(dec_node_page_state); + +void __dec_node_page_state(struct page *page, enum node_stat_item item) +{ + mod_node_state(page_pgdat(page), item, -1, -1); +} +EXPORT_SYMBOL(__dec_node_page_state); +#else /* * For use when we know that interrupts are disabled, * or when we know that preemption is disabled and that @@ -541,149 +723,6 @@ void __dec_node_page_state(struct page * } EXPORT_SYMBOL(__dec_node_page_state); =20 -#ifdef CONFIG_HAVE_CMPXCHG_LOCAL -/* - * If we have cmpxchg_local support then we do not need to incur the overh= ead - * that comes with local_irq_save/restore if we use this_cpu_cmpxchg. - * - * mod_state() modifies the zone counter state through atomic per cpu - * operations. - * - * Overstep mode specifies how overstep should handled: - * 0 No overstepping - * 1 Overstepping half of threshold - * -1 Overstepping minus half of threshold -*/ -static inline void mod_zone_state(struct zone *zone, - enum zone_stat_item item, long delta, int overstep_mode) -{ - struct per_cpu_zonestat __percpu *pcp =3D zone->per_cpu_zonestats; - s8 __percpu *p =3D pcp->vm_stat_diff + item; - long o, n, t, z; - - do { - z =3D 0; /* overflow to zone counters */ - - /* - * The fetching of the stat_threshold is racy. We may apply - * a counter threshold to the wrong the cpu if we get - * rescheduled while executing here. However, the next - * counter update will apply the threshold again and - * therefore bring the counter under the threshold again. - * - * Most of the time the thresholds are the same anyways - * for all cpus in a zone. - */ - t =3D this_cpu_read(pcp->stat_threshold); - - o =3D this_cpu_read(*p); - n =3D delta + o; - - if (abs(n) > t) { - int os =3D overstep_mode * (t >> 1) ; - - /* Overflow must be added to zone counters */ - z =3D n + os; - n =3D -os; - } - } while (this_cpu_cmpxchg(*p, o, n) !=3D o); - - if (z) - zone_page_state_add(z, zone, item); -} - -void mod_zone_page_state(struct zone *zone, enum zone_stat_item item, - long delta) -{ - mod_zone_state(zone, item, delta, 0); -} -EXPORT_SYMBOL(mod_zone_page_state); - -void inc_zone_page_state(struct page *page, enum zone_stat_item item) -{ - mod_zone_state(page_zone(page), item, 1, 1); -} -EXPORT_SYMBOL(inc_zone_page_state); - -void dec_zone_page_state(struct page *page, enum zone_stat_item item) -{ - mod_zone_state(page_zone(page), item, -1, -1); -} -EXPORT_SYMBOL(dec_zone_page_state); - -static inline void mod_node_state(struct pglist_data *pgdat, - enum node_stat_item item, int delta, int overstep_mode) -{ - struct per_cpu_nodestat __percpu *pcp =3D pgdat->per_cpu_nodestats; - s8 __percpu *p =3D pcp->vm_node_stat_diff + item; - long o, n, t, z; - - if (vmstat_item_in_bytes(item)) { - /* - * Only cgroups use subpage accounting right now; at - * the global level, these items still change in - * multiples of whole pages. Store them as pages - * internally to keep the per-cpu counters compact. - */ - VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1)); - delta >>=3D PAGE_SHIFT; - } - - do { - z =3D 0; /* overflow to node counters */ - - /* - * The fetching of the stat_threshold is racy. We may apply - * a counter threshold to the wrong the cpu if we get - * rescheduled while executing here. However, the next - * counter update will apply the threshold again and - * therefore bring the counter under the threshold again. - * - * Most of the time the thresholds are the same anyways - * for all cpus in a node. - */ - t =3D this_cpu_read(pcp->stat_threshold); - - o =3D this_cpu_read(*p); - n =3D delta + o; - - if (abs(n) > t) { - int os =3D overstep_mode * (t >> 1) ; - - /* Overflow must be added to node counters */ - z =3D n + os; - n =3D -os; - } - } while (this_cpu_cmpxchg(*p, o, n) !=3D o); - - if (z) - node_page_state_add(z, pgdat, item); -} - -void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item it= em, - long delta) -{ - mod_node_state(pgdat, item, delta, 0); -} -EXPORT_SYMBOL(mod_node_page_state); - -void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item) -{ - mod_node_state(pgdat, item, 1, 1); -} - -void inc_node_page_state(struct page *page, enum node_stat_item item) -{ - mod_node_state(page_pgdat(page), item, 1, 1); -} -EXPORT_SYMBOL(inc_node_page_state); - -void dec_node_page_state(struct page *page, enum node_stat_item item) -{ - mod_node_state(page_pgdat(page), item, -1, -1); -} -EXPORT_SYMBOL(dec_node_page_state); -#else /* * Use interrupt disable to serialize counter updates */ Index: linux-vmstat-remote/mm/page_alloc.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/mm/page_alloc.c +++ linux-vmstat-remote/mm/page_alloc.c @@ -8608,9 +8608,6 @@ static int page_alloc_cpu_dead(unsigned /* * Zero the differential counters of the dead processor * so that the vm statistics are consistent. - * - * This is only okay since the processor is dead and cannot - * race with what we are doing. */ cpu_vm_stats_fold(cpu); From nobody Sat Apr 11 08:26:27 2026 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 C3384C7EE32 for ; Fri, 3 Mar 2023 20:02:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231674AbjCCUCG (ORCPT ); Fri, 3 Mar 2023 15:02:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231539AbjCCUBf (ORCPT ); Fri, 3 Mar 2023 15:01:35 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB543618A1 for ; Fri, 3 Mar 2023 12:00:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677873637; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=YjZzxvwbzUGJAOWGom5FEayhMjnpZ78I4D4VtdieNs8=; b=hG15rrNB4QDk+bbjylSVqLEqW76YTZWhkpPv5cAsJWtm1dIGcYTNMeI9iHBMRvKfTWpaNk dxETyLILqoJ/ZNxWT5YWQjOdosTiVr+/mlgZ3ljrc19wqkAszdbmz4XQ5D6TiI5JCJrEVN +KyeLm+XpVZG0jj4z62f8mFYGj9FnDA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-600-0hR5pFVRPFKmnp7Mr7Vb7w-1; Fri, 03 Mar 2023 15:00:33 -0500 X-MC-Unique: 0hR5pFVRPFKmnp7Mr7Vb7w-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5C821101B44E; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2D92C4014EB9; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id ABA1542919632; Fri, 3 Mar 2023 17:00:12 -0300 (-03) Message-ID: <20230303195908.977788434@redhat.com> User-Agent: quilt/0.67 Date: Fri, 03 Mar 2023 16:58:50 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Russell King , Huacai Chen , Heiko Carstens , x86@kernel.org, Marcelo Tosatti Subject: [PATCH v3 09/11] mm/vmstat: use xchg in cpu_vm_stats_fold References: <20230303195841.310844446@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" In preparation to switch vmstat shepherd to flush per-CPU counters remotely, use xchg instead of a pair of read/write instructions. Signed-off-by: Marcelo Tosatti Index: linux-vmstat-remote/mm/vmstat.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/mm/vmstat.c +++ linux-vmstat-remote/mm/vmstat.c @@ -883,7 +883,7 @@ static int refresh_cpu_vm_stats(void) } =20 /* - * Fold the data for an offline cpu into the global array. + * Fold the data for a cpu into the global array. * There cannot be any access by the offline cpu and therefore * synchronization is simplified. */ @@ -904,8 +904,7 @@ void cpu_vm_stats_fold(int cpu) if (pzstats->vm_stat_diff[i]) { int v; =20 - v =3D pzstats->vm_stat_diff[i]; - pzstats->vm_stat_diff[i] =3D 0; + v =3D xchg(&pzstats->vm_stat_diff[i], 0); atomic_long_add(v, &zone->vm_stat[i]); global_zone_diff[i] +=3D v; } @@ -915,8 +914,7 @@ void cpu_vm_stats_fold(int cpu) if (pzstats->vm_numa_event[i]) { unsigned long v; =20 - v =3D pzstats->vm_numa_event[i]; - pzstats->vm_numa_event[i] =3D 0; + v =3D xchg(&pzstats->vm_numa_event[i], 0); zone_numa_event_add(v, zone, i); } } @@ -932,8 +930,7 @@ void cpu_vm_stats_fold(int cpu) if (p->vm_node_stat_diff[i]) { int v; =20 - v =3D p->vm_node_stat_diff[i]; - p->vm_node_stat_diff[i] =3D 0; + v =3D xchg(&p->vm_node_stat_diff[i], 0); atomic_long_add(v, &pgdat->vm_stat[i]); global_node_diff[i] +=3D v; } From nobody Sat Apr 11 08:26:27 2026 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 17DAEC64EC4 for ; Fri, 3 Mar 2023 20:01:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231588AbjCCUBo (ORCPT ); Fri, 3 Mar 2023 15:01:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56112 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231150AbjCCUBa (ORCPT ); Fri, 3 Mar 2023 15:01:30 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28C736153E for ; Fri, 3 Mar 2023 12:00:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677873635; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=tHAQYo4aXRrl160KH7pJqqqPegg14fiAPRCJhIKS8fE=; b=amJWYAbXDqM2W/gUg/nTITXsXKHGKFk523FOEukKdQvP9cs1nibQGukMk3/20rL8K5G40U Tjf0CoZGrzAkzNoYwbuyBSUqFAnfMR6sgpiJsECd2iIDEmAeGJ4P99ZOxyLEwZfa2NUF+l QRYjlpyipw+BKp1Fzg8VP8Tcij+C23s= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-294-29M75UO_NkSSiK0Vpi9pvg-1; Fri, 03 Mar 2023 15:00:31 -0500 X-MC-Unique: 29M75UO_NkSSiK0Vpi9pvg-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 55C1A803491; Fri, 3 Mar 2023 20:00:30 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2861A492B00; Fri, 3 Mar 2023 20:00:30 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id AFB1442919633; Fri, 3 Mar 2023 17:00:12 -0300 (-03) Message-ID: <20230303195909.003776725@redhat.com> User-Agent: quilt/0.67 Date: Fri, 03 Mar 2023 16:58:51 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Russell King , Huacai Chen , Heiko Carstens , x86@kernel.org, Marcelo Tosatti Subject: [PATCH v3 10/11] mm/vmstat: switch vmstat shepherd to flush per-CPU counters remotely References: <20230303195841.310844446@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Now that the counters are modified via cmpxchg both CPU locally (via the account functions), and remotely (via cpu_vm_stats_fold), its possible to switch vmstat_shepherd to perform the per-CPU=20 vmstats folding remotely. This fixes the following two problems: 1. A customer provided some evidence which indicates that the idle tick was stopped; albeit, CPU-specific vmstat counters still remained populated. Thus one can only assume quiet_vmstat() was not invoked on return to the idle loop. If I understand correctly, I suspect this divergence might erroneously prevent a reclaim attempt by kswapd. If the number of zone specific free pages are below their per-cpu drift value then zone_page_state_snapshot() is used to compute a more accurate view of the aforementioned statistic. Thus any task blocked on the NUMA node specific pfmemalloc_wait queue will be unable to make significant progress via direct reclaim unless it is killed after being woken up by kswapd (see throttle_direct_reclaim()) 2. With a SCHED_FIFO task that busy loops on a given CPU, and kworker for that CPU at SCHED_OTHER priority, queuing work to sync per-vmstats will either cause that work to never execute, or stalld (i.e. stall daemon) boosts kworker priority which causes a latency violation Signed-off-by: Marcelo Tosatti Index: linux-vmstat-remote/mm/vmstat.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/mm/vmstat.c +++ linux-vmstat-remote/mm/vmstat.c @@ -2004,6 +2004,23 @@ static void vmstat_shepherd(struct work_ =20 static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd); =20 +#ifdef CONFIG_HAVE_CMPXCHG_LOCAL +/* Flush counters remotely if CPU uses cmpxchg to update its per-CPU count= ers */ +static void vmstat_shepherd(struct work_struct *w) +{ + int cpu; + + cpus_read_lock(); + for_each_online_cpu(cpu) { + cpu_vm_stats_fold(cpu); + cond_resched(); + } + cpus_read_unlock(); + + schedule_delayed_work(&shepherd, + round_jiffies_relative(sysctl_stat_interval)); +} +#else static void vmstat_shepherd(struct work_struct *w) { int cpu; @@ -2023,6 +2040,7 @@ static void vmstat_shepherd(struct work_ schedule_delayed_work(&shepherd, round_jiffies_relative(sysctl_stat_interval)); } +#endif =20 static void __init start_shepherd_timer(void) { From nobody Sat Apr 11 08:26:27 2026 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 9D4DBC64EC4 for ; Fri, 3 Mar 2023 20:02:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231636AbjCCUB6 (ORCPT ); Fri, 3 Mar 2023 15:01:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231538AbjCCUBf (ORCPT ); Fri, 3 Mar 2023 15:01:35 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B974B60A88 for ; Fri, 3 Mar 2023 12:00:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677873637; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=HEd4Z20qHewy4816S06cVIYXHbFUi/GbntWDJMKAj40=; b=HlHhTNWFB/lIB4oewSYfnJNqQi9uzsmYXovDUQCFYQsbLdHWD4U1IoUS4nHfMe2Uv2VFGc mZnWFFW7ou3q+zYdUFUJOWmSK2808Ov/NS1YbTNykho3dpOuXWUvvJlsu06jERKDZuhO7G eHekWoykK3h2Idepu8UoDLFKcUjleGk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-643-joKSBS7lOOC_ZiriZUzjGQ-1; Fri, 03 Mar 2023 15:00:33 -0500 X-MC-Unique: joKSBS7lOOC_ZiriZUzjGQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 42FA480D0F3; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: from tpad.localdomain (ovpn-112-2.gru2.redhat.com [10.97.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 17CA02026D4B; Fri, 3 Mar 2023 20:00:32 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id B4B3642919634; Fri, 3 Mar 2023 17:00:12 -0300 (-03) Message-ID: <20230303195909.029065935@redhat.com> User-Agent: quilt/0.67 Date: Fri, 03 Mar 2023 16:58:52 -0300 From: Marcelo Tosatti To: Christoph Lameter Cc: Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Russell King , Huacai Chen , Heiko Carstens , x86@kernel.org, Marcelo Tosatti Subject: [PATCH v3 11/11] mm/vmstat: refresh stats remotely instead of via work item References: <20230303195841.310844446@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Refresh per-CPU stats remotely, instead of queueing=20 work items, for the stat_refresh procfs method. This fixes sosreport hang (which uses vmstat_refresh) with spinning SCHED_FIFO process. Signed-off-by: Marcelo Tosatti Index: linux-vmstat-remote/mm/vmstat.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-vmstat-remote.orig/mm/vmstat.c +++ linux-vmstat-remote/mm/vmstat.c @@ -1860,11 +1860,21 @@ static DEFINE_PER_CPU(struct delayed_wor int sysctl_stat_interval __read_mostly =3D HZ; =20 #ifdef CONFIG_PROC_FS + +#ifdef CONFIG_HAVE_CMPXCHG_LOCAL +static int refresh_all_vm_stats(void); +#else static void refresh_vm_stats(struct work_struct *work) { refresh_cpu_vm_stats(); } =20 +static int refresh_all_vm_stats(void) +{ + return schedule_on_each_cpu(refresh_vm_stats); +} +#endif + int vmstat_refresh(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { @@ -1886,7 +1896,7 @@ int vmstat_refresh(struct ctl_table *tab * transiently negative values, report an error here if any of * the stats is negative, so we know to go looking for imbalance. */ - err =3D schedule_on_each_cpu(refresh_vm_stats); + err =3D refresh_all_vm_stats(); if (err) return err; for (i =3D 0; i < NR_VM_ZONE_STAT_ITEMS; i++) { @@ -2006,7 +2016,7 @@ static DECLARE_DEFERRABLE_WORK(shepherd, =20 #ifdef CONFIG_HAVE_CMPXCHG_LOCAL /* Flush counters remotely if CPU uses cmpxchg to update its per-CPU count= ers */ -static void vmstat_shepherd(struct work_struct *w) +static int refresh_all_vm_stats(void) { int cpu; =20 @@ -2016,7 +2026,12 @@ static void vmstat_shepherd(struct work_ cond_resched(); } cpus_read_unlock(); + return 0; +} =20 +static void vmstat_shepherd(struct work_struct *w) +{ + refresh_all_vm_stats(); schedule_delayed_work(&shepherd, round_jiffies_relative(sysctl_stat_interval)); }