From nobody Wed Feb 11 16:10:16 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 5C5B4C61DA4 for ; Mon, 13 Mar 2023 16:30:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231379AbjCMQaD (ORCPT ); Mon, 13 Mar 2023 12:30:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50988 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231343AbjCMQ3H (ORCPT ); Mon, 13 Mar 2023 12:29:07 -0400 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 11BC47A91E for ; Mon, 13 Mar 2023 09:27:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678724867; 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=R9glNPjQ9JH41ZUUhZm78C36m6D7U/izmO00owo2Xjm/m6eHJapvMEmTvr7RTjHBlhfW8t anaNQC4wC79oXfRssqtONlYHzYmI93UG72fyYBcaoflIG61SKF7qsuD5RrPVUE8pkaawRt cY1gHCzGHxrYsg2LMxtiI46QmzaDhI0= 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-256-_i-nT0qoM-Wt4M1D21UMfQ-1; Mon, 13 Mar 2023 12:27:40 -0400 X-MC-Unique: _i-nT0qoM-Wt4M1D21UMfQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 32BC618E0044; Mon, 13 Mar 2023 16:27:40 +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 E93CA1121318; Mon, 13 Mar 2023 16:27:39 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 11E84401344A4; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.283504192@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:08 -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, Vlastimil Babka , Marcelo Tosatti Subject: [PATCH v5 01/12] this_cpu_cmpxchg: ARM64: switch this_cpu_cmpxchg to locked, add _local function References: <20230313162507.032200398@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 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 Wed Feb 11 16:10:16 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 A6F55C6FD19 for ; Mon, 13 Mar 2023 16:29:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231408AbjCMQ3U (ORCPT ); Mon, 13 Mar 2023 12:29:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231330AbjCMQ3A (ORCPT ); Mon, 13 Mar 2023 12:29:00 -0400 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 C459D7A907 for ; Mon, 13 Mar 2023 09:27:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678724866; 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=AwMGNxuLKVSaBiNlIyxU0qNHq1G6nH3pjjT2RXTiA/3NkKnLWe1eEnTFfb7t4PvvlB2JNe 5ZIWP//DNcEbVgBa9+bQCzdsOUf2V+t0eR4rUCUvsuQQHU+0b2LscicKIXzrCHDZBWjRgf htGyx+C0Gm/t/9MINJozO/KtWzx1kAk= 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-131-IclwUQ-EOE-jUgKOuaRX4Q-1; Mon, 13 Mar 2023 12:27:42 -0400 X-MC-Unique: IclwUQ-EOE-jUgKOuaRX4Q-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CAABD3C0D18B; Mon, 13 Mar 2023 16:27:41 +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 9A1CD140E991; Mon, 13 Mar 2023 16:27:41 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 156F940153588; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.309252817@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:09 -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, Vlastimil Babka , Marcelo Tosatti Subject: [PATCH v5 02/12] this_cpu_cmpxchg: loongarch: switch this_cpu_cmpxchg to locked, add _local function References: <20230313162507.032200398@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 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 Wed Feb 11 16:10:16 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 5A1E1C6FD19 for ; Mon, 13 Mar 2023 16:29:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230510AbjCMQ3J (ORCPT ); Mon, 13 Mar 2023 12:29:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231314AbjCMQ27 (ORCPT ); Mon, 13 Mar 2023 12:28:59 -0400 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 93D3C79B3D for ; Mon, 13 Mar 2023 09:27:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678724863; 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=QG3Jtyex1mPPAnDb92thpz1Oo1U+aA3pcYsw9KLmg7TSCi3dgzbnMeyO5KwPOqBTjlaIpS FYnzdgYOxOn4XKlG3eBf5Lrba1Dk9XOZy6s+oAM352O7ThGBMScylnZ6RsjxsN/Ycac2Hs tETs+wXZVO1C43Cc6SQgl6Q0aiO4w3Q= 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-336-rgJUFS3UNpO8OZyHkd8jqg-1; Mon, 13 Mar 2023 12:27:42 -0400 X-MC-Unique: rgJUFS3UNpO8OZyHkd8jqg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D28E680280D; Mon, 13 Mar 2023 16:27:41 +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 A603C140E96A; Mon, 13 Mar 2023 16:27:41 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 17C3B401CB959; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.333370216@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:10 -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, Vlastimil Babka , Marcelo Tosatti Subject: [PATCH v5 03/12] this_cpu_cmpxchg: S390: switch this_cpu_cmpxchg to locked, add _local function References: <20230313162507.032200398@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 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 Wed Feb 11 16:10:16 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 2B05EC6FD19 for ; Mon, 13 Mar 2023 16:29:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231479AbjCMQ3p (ORCPT ); Mon, 13 Mar 2023 12:29:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231335AbjCMQ3F (ORCPT ); Mon, 13 Mar 2023 12:29:05 -0400 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 8AE8379B15 for ; Mon, 13 Mar 2023 09:27:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678724868; 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=Ks9A+Y+Ue+vODelrx5yLeCPN5qbfxcn+9y7bXNXzDbns+pov0IIQAnLXNktfGVF2kTlpxP 4GmP/ijj//psPkWO9X1cglGez9YUfHIbbRxhOgMmKysEW1j+1F2KB/pxyv6LsHyr3BWtEl oD0iE/GN4wO104ZclxPRIS/SofCtnEs= 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-391-Zn_ZEv9WPYGg8gX5FrCE0Q-1; Mon, 13 Mar 2023 12:27:43 -0400 X-MC-Unique: Zn_ZEv9WPYGg8gX5FrCE0Q-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 0723D85CBE9; Mon, 13 Mar 2023 16:27:42 +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 A8FAF40C6E67; Mon, 13 Mar 2023 16:27:41 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 1B95E4038A1E1; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.359258017@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:11 -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, Vlastimil Babka , Marcelo Tosatti Subject: [PATCH v5 04/12] this_cpu_cmpxchg: x86: switch this_cpu_cmpxchg to locked, add _local function References: <20230313162507.032200398@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 Wed Feb 11 16:10:16 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 C87C0C6FD19 for ; Mon, 13 Mar 2023 16:29:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231426AbjCMQ31 (ORCPT ); Mon, 13 Mar 2023 12:29:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231247AbjCMQ3C (ORCPT ); Mon, 13 Mar 2023 12:29:02 -0400 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 BEDE479B2E for ; Mon, 13 Mar 2023 09:27:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678724864; 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=HSudOZjEEfr2uPyzpQtiF5iKvVWvQ3jVBUVZAm1l/SSxfHzP/azl0sUuOWkgbHk72ybQ7e 06CvvPcUoOi1Y/4NAK8mHdN3ITiKG0joc2JkM4/0jKMIpVJdRce7k9tC80U2tCtfVznKaZ D5ywHeINLerDDVNow2we8nlRYMYKtRA= 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-336-mFgJK7bbMs6HbOsxZVqtVA-1; Mon, 13 Mar 2023 12:27:42 -0400 X-MC-Unique: mFgJK7bbMs6HbOsxZVqtVA-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 DA28F3814947; Mon, 13 Mar 2023 16:27:41 +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 AB14C40C6E68; Mon, 13 Mar 2023 16:27:41 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 1EF8E4038A1E6; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.383217649@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:12 -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, Vlastimil Babka , Marcelo Tosatti Subject: [PATCH v5 05/12] add this_cpu_cmpxchg_local and asm-generic definitions References: <20230313162507.032200398@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. 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 Wed Feb 11 16:10:16 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 0F575C6FD19 for ; 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Mon, 13 Mar 2023 12:27:43 -0400 X-MC-Unique: kVC4bivEN-u7qO5pSUEO8w-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 322263C0D1AE; Mon, 13 Mar 2023 16:27:42 +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 F07B23542A; Mon, 13 Mar 2023 16:27:41 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 25FC74038A1F2; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.408562151@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:13 -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, Vlastimil Babka , Peter Xu , Marcelo Tosatti Subject: [PATCH v5 06/12] convert this_cpu_cmpxchg users to this_cpu_cmpxchg_local References: <20230313162507.032200398@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" 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 Wed Feb 11 16:10:16 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 DF801C6FD1F for ; Mon, 13 Mar 2023 16:29:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231434AbjCMQ3a (ORCPT ); Mon, 13 Mar 2023 12:29:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231256AbjCMQ3C (ORCPT ); Mon, 13 Mar 2023 12:29:02 -0400 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 6562279B27 for ; Mon, 13 Mar 2023 09:27:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678724864; 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=HRaKPhoc2o/dyfmAGwpM6cYdTDahEMUEDBWaTmQOBWk=; b=TrQ7L57h5rd5rYyegsk9AtlahD31LADJOLq6jCwa5zMkx4KNKOwGNjLFxUQ/JHX92s0d8o S3ftno+11PZzDtLKP72zmk7pSSixGXGj/Ceq1IPsqUoCL5noJ5bV5Kl0+ccPCWcS6LxDTy wNAWGoUhN8N51ZJgoDN6HsuB3++cdPY= 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-447-m-vIZTaiPO-3HnJowFEtqw-1; Mon, 13 Mar 2023 12:27:43 -0400 X-MC-Unique: m-vIZTaiPO-3HnJowFEtqw-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 52AC985CBEB; Mon, 13 Mar 2023 16:27:42 +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 F0662492C13; Mon, 13 Mar 2023 16:27:41 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 29EC94038A1F7; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.433875205@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:14 -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, Vlastimil Babka , Marcelo Tosatti Subject: [PATCH v5 07/12] mm/vmstat: switch counter modification to cmpxchg References: <20230313162507.032200398@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 @@ -8628,9 +8628,6 @@ 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 Wed Feb 11 16:10:16 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 20F3EC6FD19 for ; Mon, 13 Mar 2023 16:30:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231350AbjCMQ37 (ORCPT ); Mon, 13 Mar 2023 12:29:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50320 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231344AbjCMQ3H (ORCPT ); Mon, 13 Mar 2023 12:29:07 -0400 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 A98787A91B for ; Mon, 13 Mar 2023 09:27:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678724866; 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=eQHLLQ5PDSU2xDgYL5oReXWI8s5CvUHAEWJjGfc5xCc=; b=MqP5YR+eW+rbc6qGvs2sJS7Q/OhgMxFwoAWG8kKMIsiAttq1YqF6+2wwdSbejVd7adIjmF uIcHR+lqYbWcPEbdOoMRn194u6MD3IKcBkW/ifUW08Uj7c2irM3t7kQuIhVBG7CZE70i1O vAttIkeQaYmuvDG4smOK9mq+grIDLLY= 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-447-fKD2GMTTMDiEEVthat5a4Q-1; Mon, 13 Mar 2023 12:27:43 -0400 X-MC-Unique: fKD2GMTTMDiEEVthat5a4Q-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 2294D811E6E; Mon, 13 Mar 2023 16:27:42 +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 B775E202701E; Mon, 13 Mar 2023 16:27:41 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 305264038A1FF; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.458451052@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:15 -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, Vlastimil Babka , Marcelo Tosatti Subject: [PATCH v5 08/12] vmstat: switch per-cpu vmstat counters to 32-bits References: <20230313162507.032200398@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" Some architectures only provide xchg/cmpxchg in 32/64-bit quantities. Since the next patch is about to use xchg on per-CPU vmstat counters, switch them to s32. 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 @@ -689,8 +689,8 @@ struct per_cpu_pages { =20 struct per_cpu_zonestat { #ifdef CONFIG_SMP - s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS]; - s8 stat_threshold; + s32 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS]; + s32 stat_threshold; #endif #ifdef CONFIG_NUMA /* @@ -703,8 +703,8 @@ struct per_cpu_zonestat { }; =20 struct per_cpu_nodestat { - s8 stat_threshold; - s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS]; + s32 stat_threshold; + s32 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS]; }; =20 #endif /* !__GENERATING_BOUNDS.H */ 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 @@ -351,7 +351,7 @@ static inline void mod_zone_state(struct 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; + s32 __percpu *p =3D pcp->vm_stat_diff + item; long o, n, t, z; =20 do { @@ -428,7 +428,7 @@ static inline void mod_node_state(struct 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; + s32 __percpu *p =3D pcp->vm_node_stat_diff + item; long o, n, t, z; =20 if (vmstat_item_in_bytes(item)) { @@ -525,7 +525,7 @@ void __mod_zone_page_state(struct zone * long delta) { struct per_cpu_zonestat __percpu *pcp =3D zone->per_cpu_zonestats; - s8 __percpu *p =3D pcp->vm_stat_diff + item; + s32 __percpu *p =3D pcp->vm_stat_diff + item; long x; long t; =20 @@ -556,7 +556,7 @@ void __mod_node_page_state(struct pglist long delta) { struct per_cpu_nodestat __percpu *pcp =3D pgdat->per_cpu_nodestats; - s8 __percpu *p =3D pcp->vm_node_stat_diff + item; + s32 __percpu *p =3D pcp->vm_node_stat_diff + item; long x; long t; =20 @@ -614,8 +614,8 @@ EXPORT_SYMBOL(__mod_node_page_state); void __inc_zone_state(struct zone *zone, enum zone_stat_item item) { struct per_cpu_zonestat __percpu *pcp =3D zone->per_cpu_zonestats; - s8 __percpu *p =3D pcp->vm_stat_diff + item; - s8 v, t; + s32 __percpu *p =3D pcp->vm_stat_diff + item; + s32 v, t; =20 /* See __mod_node_page_state */ preempt_disable_nested(); @@ -623,7 +623,7 @@ void __inc_zone_state(struct zone *zone, v =3D __this_cpu_inc_return(*p); t =3D __this_cpu_read(pcp->stat_threshold); if (unlikely(v > t)) { - s8 overstep =3D t >> 1; + s32 overstep =3D t >> 1; =20 zone_page_state_add(v + overstep, zone, item); __this_cpu_write(*p, -overstep); @@ -635,8 +635,8 @@ void __inc_zone_state(struct zone *zone, void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item) { struct per_cpu_nodestat __percpu *pcp =3D pgdat->per_cpu_nodestats; - s8 __percpu *p =3D pcp->vm_node_stat_diff + item; - s8 v, t; + s32 __percpu *p =3D pcp->vm_node_stat_diff + item; + s32 v, t; =20 VM_WARN_ON_ONCE(vmstat_item_in_bytes(item)); =20 @@ -646,7 +646,7 @@ void __inc_node_state(struct pglist_data v =3D __this_cpu_inc_return(*p); t =3D __this_cpu_read(pcp->stat_threshold); if (unlikely(v > t)) { - s8 overstep =3D t >> 1; + s32 overstep =3D t >> 1; =20 node_page_state_add(v + overstep, pgdat, item); __this_cpu_write(*p, -overstep); @@ -670,8 +670,8 @@ EXPORT_SYMBOL(__inc_node_page_state); void __dec_zone_state(struct zone *zone, enum zone_stat_item item) { struct per_cpu_zonestat __percpu *pcp =3D zone->per_cpu_zonestats; - s8 __percpu *p =3D pcp->vm_stat_diff + item; - s8 v, t; + s32 __percpu *p =3D pcp->vm_stat_diff + item; + s32 v, t; =20 /* See __mod_node_page_state */ preempt_disable_nested(); @@ -679,7 +679,7 @@ void __dec_zone_state(struct zone *zone, v =3D __this_cpu_dec_return(*p); t =3D __this_cpu_read(pcp->stat_threshold); if (unlikely(v < - t)) { - s8 overstep =3D t >> 1; + s32 overstep =3D t >> 1; =20 zone_page_state_add(v - overstep, zone, item); __this_cpu_write(*p, overstep); @@ -691,8 +691,8 @@ void __dec_zone_state(struct zone *zone, void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item) { struct per_cpu_nodestat __percpu *pcp =3D pgdat->per_cpu_nodestats; - s8 __percpu *p =3D pcp->vm_node_stat_diff + item; - s8 v, t; + s32 __percpu *p =3D pcp->vm_node_stat_diff + item; + s32 v, t; =20 VM_WARN_ON_ONCE(vmstat_item_in_bytes(item)); =20 @@ -702,7 +702,7 @@ void __dec_node_state(struct pglist_data v =3D __this_cpu_dec_return(*p); t =3D __this_cpu_read(pcp->stat_threshold); if (unlikely(v < - t)) { - s8 overstep =3D t >> 1; + s32 overstep =3D t >> 1; =20 node_page_state_add(v - overstep, pgdat, item); __this_cpu_write(*p, overstep); From nobody Wed Feb 11 16:10:16 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 C2FFAC6FD1F for ; Mon, 13 Mar 2023 16:29:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230081AbjCMQ3N (ORCPT ); Mon, 13 Mar 2023 12:29:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50820 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230254AbjCMQ3A (ORCPT ); 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Mon, 13 Mar 2023 16:27:42 +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 C9959400F4F; Mon, 13 Mar 2023 16:27:41 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 348BF4038AB89; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.482796394@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:16 -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, Vlastimil Babka , Marcelo Tosatti Subject: [PATCH v5 09/12] mm/vmstat: use xchg in cpu_vm_stats_fold References: <20230313162507.032200398@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" 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 @@ -924,7 +924,7 @@ static int refresh_cpu_vm_stats(bool do_ } =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. */ @@ -945,8 +945,7 @@ 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; } @@ -956,8 +955,7 @@ 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); } } @@ -973,8 +971,7 @@ 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 Wed Feb 11 16:10:16 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 8FAB1C6FD1F for ; Mon, 13 Mar 2023 16:29:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229684AbjCMQ3d (ORCPT ); Mon, 13 Mar 2023 12:29:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229968AbjCMQ3D (ORCPT ); Mon, 13 Mar 2023 12:29:03 -0400 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 8D4007A916 for ; Mon, 13 Mar 2023 09:27:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678724866; 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=tZRdfptRFY5Vlp762UsZ6/anX9gl/kIpoSRft9xlHEw=; b=LkVeQsIpg4eov5ys/gCa7TqaVVh+yMyluryLRj681wNyA6jewTXz+Fkz/MioR1Fx8SYZ0j 0LS9cf+YPsUJV/tjewCILWYjvcXGYltv41i7YBH5y9+/z6T9v5I/pI5+Ny64JoGTwXb6+1 U+EfEGo32/ZlxVA0lHVsTgOO82uiBHw= 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-126-Z4BMmYaWPeK5kERbohyfSA-1; Mon, 13 Mar 2023 12:27:43 -0400 X-MC-Unique: Z4BMmYaWPeK5kERbohyfSA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0022B3814949; Mon, 13 Mar 2023 16:27:42 +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 C6F47C164E7; Mon, 13 Mar 2023 16:27:41 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 38FD44038AB8A; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.509267576@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:17 -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, Vlastimil Babka , Marcelo Tosatti Subject: [PATCH v5 10/12] mm/vmstat: switch vmstat shepherd to flush per-CPU counters remotely References: <20230313162507.032200398@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 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 @@ -2043,6 +2043,23 @@ 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; @@ -2062,6 +2079,7 @@ 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 Wed Feb 11 16:10:16 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 13237C6FD19 for ; Mon, 13 Mar 2023 16:29:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231145AbjCMQ35 (ORCPT ); Mon, 13 Mar 2023 12:29:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231350AbjCMQ3H (ORCPT ); Mon, 13 Mar 2023 12:29:07 -0400 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 07E8F7A9F for ; Mon, 13 Mar 2023 09:27:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678724879; 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=BjYqqe7MvmRoNdsZ3mRmEvGJpIWPHc0RoB3EQFJD7pE=; b=WkX6ahfllsQsh3Yv6JcHfTUajZSE2NtI7ZLuF04twEQljh22NEXsb93v5d0L/YnOklHU4N axl039FtweTj/Dyr/op1dq7Zsa61oS0DuA6c/lxF7pv7fozSWZ+cywNQMLC84YLCo2lv60 XQ+qo1vrlLVzvYhRo7BvxYy+drGMHNs= 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-391-PN2FRtEPOj6OfPOguGKUAg-1; Mon, 13 Mar 2023 12:27:42 -0400 X-MC-Unique: PN2FRtEPOj6OfPOguGKUAg-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 F15C23C0D1AC; Mon, 13 Mar 2023 16:27:41 +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 C736440C6E69; Mon, 13 Mar 2023 16:27:41 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 3EBD84038AB8B; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.535939407@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:18 -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, Vlastimil Babka , Marcelo Tosatti Subject: [PATCH v5 11/12] mm/vmstat: refresh stats remotely instead of via work item References: <20230313162507.032200398@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" 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 @@ -1901,11 +1901,20 @@ 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(true); } =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) { @@ -1925,7 +1934,7 @@ 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++) { @@ -2045,7 +2054,7 @@ 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 @@ -2055,7 +2064,12 @@ 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)); } From nobody Wed Feb 11 16:10:16 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 4EC24C61DA4 for ; Mon, 13 Mar 2023 16:29:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231351AbjCMQ3H (ORCPT ); Mon, 13 Mar 2023 12:29:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231309AbjCMQ27 (ORCPT ); Mon, 13 Mar 2023 12:28:59 -0400 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 EE4757A90B for ; Mon, 13 Mar 2023 09:27:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678724865; 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=s8sJ/cpBUh6LGMZ+lcAYSBuSqrBbcVYVRwc+yqWmsjw=; b=VmieFrNyXtV1VDpHI26EEzy1xpQogJpnGOLKPqHUO0caxC5K88HncBOcMdS36ruQFdrmMi W1epDBe7fA2cN6+I8pzuYluMOpcbHmSnVM80sWg0wHKyxSmtCxkGrKrQhxyTo3E1d6Wpks j2hOLxCBZ600HdSzkd2hgB/qxVqP+yM= 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-617-ZMuT39A6OHKSVs7hfn-Tvw-1; Mon, 13 Mar 2023 12:27:41 -0400 X-MC-Unique: ZMuT39A6OHKSVs7hfn-Tvw-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 4280818E0045; Mon, 13 Mar 2023 16:27:40 +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 15EC3492C14; Mon, 13 Mar 2023 16:27:40 +0000 (UTC) Received: by tpad.localdomain (Postfix, from userid 1000) id 467DB4038AB8F; Mon, 13 Mar 2023 13:26:44 -0300 (-03) Message-ID: <20230313162634.561005765@redhat.com> User-Agent: quilt/0.67 Date: Mon, 13 Mar 2023 13:25:19 -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, Vlastimil Babka , Marcelo Tosatti Subject: [PATCH v5 12/12] vmstat: add pcp remote node draining via cpu_vm_stats_fold References: <20230313162507.032200398@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" Large NUMA systems might have significant portions=20 of system memory to be trapped in pcp queues. The number of pcp is = =20 determined by the number of processors and nodes in a system. A system = =20 with 4 processors and 2 nodes has 8 pcps which is okay. But a system = =20 with 1024 processors and 512 nodes has 512k pcps with a high potential = =20 for large amount of memory being caught in them. Enable remote node draining for the CONFIG_HAVE_CMPXCHG_LOCAL case, where vmstat_shepherd will perform the aging and draining via cpu_vm_stats_fold. Suggested-by: Vlastimil Babka 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 @@ -928,7 +928,7 @@ static int refresh_cpu_vm_stats(bool do_ * There cannot be any access by the offline cpu and therefore * synchronization is simplified. */ -void cpu_vm_stats_fold(int cpu) +void cpu_vm_stats_fold(int cpu, bool do_pagesets) { struct pglist_data *pgdat; struct zone *zone; @@ -938,6 +938,9 @@ void cpu_vm_stats_fold(int cpu) =20 for_each_populated_zone(zone) { struct per_cpu_zonestat *pzstats; +#ifdef CONFIG_NUMA + struct per_cpu_pages *pcp =3D per_cpu_ptr(zone->per_cpu_pageset, cpu); +#endif =20 pzstats =3D per_cpu_ptr(zone->per_cpu_zonestats, cpu); =20 @@ -948,6 +951,11 @@ void cpu_vm_stats_fold(int cpu) v =3D xchg(&pzstats->vm_stat_diff[i], 0); atomic_long_add(v, &zone->vm_stat[i]); global_zone_diff[i] +=3D v; +#ifdef CONFIG_NUMA + /* 3 seconds idle till flush */ + if (do_pagesets) + pcp->expire =3D 3; +#endif } } #ifdef CONFIG_NUMA @@ -959,6 +967,38 @@ void cpu_vm_stats_fold(int cpu) zone_numa_event_add(v, zone, i); } } + + if (do_pagesets) { + cond_resched(); + /* + * Deal with draining the remote pageset of a + * processor + * + * Check if there are pages remaining in this pageset + * if not then there is nothing to expire. + */ + if (!pcp->expire || !pcp->count) + continue; + + /* + * We never drain zones local to this processor. + */ + if (zone_to_nid(zone) =3D=3D cpu_to_node(cpu)) { + pcp->expire =3D 0; + continue; + } + + WARN_ON(pcp->expire < 0); + /* + * pcp->expire is only accessed from vmstat_shepherd context, + * therefore no locking is required. + */ + if (--pcp->expire) + continue; + + if (pcp->count) + drain_zone_pages(zone, pcp); + } #endif } =20 @@ -2060,7 +2100,7 @@ static int refresh_all_vm_stats(void) =20 cpus_read_lock(); for_each_online_cpu(cpu) { - cpu_vm_stats_fold(cpu); + cpu_vm_stats_fold(cpu, true); cond_resched(); } cpus_read_unlock(); Index: linux-vmstat-remote/include/linux/vmstat.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/vmstat.h +++ linux-vmstat-remote/include/linux/vmstat.h @@ -291,7 +291,7 @@ extern void __dec_zone_state(struct zone extern void __dec_node_state(struct pglist_data *, enum node_stat_item); =20 void quiet_vmstat(void); -void cpu_vm_stats_fold(int cpu); +void cpu_vm_stats_fold(int cpu, bool do_pagesets); void refresh_zone_stat_thresholds(void); =20 struct ctl_table; 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 @@ -8629,7 +8629,7 @@ static int page_alloc_cpu_dead(unsigned * Zero the differential counters of the dead processor * so that the vm statistics are consistent. */ - cpu_vm_stats_fold(cpu); + cpu_vm_stats_fold(cpu, false); =20 for_each_populated_zone(zone) zone_pcp_update(zone, 0);