From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC465C2D0DB for ; Mon, 27 Jan 2020 17:43:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9693A21739 for ; Mon, 27 Jan 2020 17:43:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="H2JjKtKD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9693A21739 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=fb.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 41BE16B0275; Mon, 27 Jan 2020 12:43:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3CE986B0276; Mon, 27 Jan 2020 12:43:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2BD746B0277; Mon, 27 Jan 2020 12:43:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0252.hostedemail.com [216.40.44.252]) by kanga.kvack.org (Postfix) with ESMTP id 134F56B0275 for ; Mon, 27 Jan 2020 12:43:06 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id D1A172825 for ; Mon, 27 Jan 2020 17:43:05 +0000 (UTC) X-FDA: 76424135130.16.mist46_8f65ff06dc213 X-HE-Tag: mist46_8f65ff06dc213 X-Filterd-Recvd-Size: 6200 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Mon, 27 Jan 2020 17:43:05 +0000 (UTC) Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 00RHe6cT005038 for ; Mon, 27 Jan 2020 09:43:04 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=714IyyrqLlmmMwWXYuFDWP/tN0q9xZUFGDpQqyDLyBo=; b=H2JjKtKDkQzi1QKNWy7ydOqxtR+RPQMsA3PtazgZxCg3DZoj3U5mIxFndurs/QVScGPe fCOCqfwSwjPrvCtv1U0QOc1IwWgTEEKEetNNKuoo8UQIG/rfnJYaYbwA/aMMuPYnBu75 I4YX7sSoOWrIjinLQV4WWGKVJFumHcPo/3o= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 2xs690e9da-9 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 27 Jan 2020 09:43:04 -0800 Received: from intmgw004.06.prn3.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:21d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Mon, 27 Jan 2020 09:43:03 -0800 Received: by devvm2643.prn2.facebook.com (Postfix, from userid 111017) id AD8711DFEFC89; Mon, 27 Jan 2020 09:35:07 -0800 (PST) Smtp-Origin-Hostprefix: devvm From: Roman Gushchin Smtp-Origin-Hostname: devvm2643.prn2.facebook.com To: , Andrew Morton CC: Michal Hocko , Johannes Weiner , Shakeel Butt , Vladimir Davydov , , , Bharata B Rao , Yafang Shao , Roman Gushchin Smtp-Origin-Cluster: prn2c23 Subject: [PATCH v2 12/28] mm: vmstat: use s32 for vm_node_stat_diff in struct per_cpu_nodestat Date: Mon, 27 Jan 2020 09:34:37 -0800 Message-ID: <20200127173453.2089565-13-guro@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200127173453.2089565-1-guro@fb.com> References: <20200127173453.2089565-1-guro@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-01-27_06:2020-01-24,2020-01-27 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 phishscore=0 impostorscore=0 mlxlogscore=999 spamscore=0 priorityscore=1501 adultscore=0 mlxscore=0 malwarescore=0 lowpriorityscore=0 bulkscore=0 suspectscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1911200001 definitions=main-2001270142 X-FB-Internal: deliver X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Currently s8 type is used for per-cpu caching of per-node statistics. It works fine because the overfill threshold can't exceed 125. But if some counters are in bytes (and the next commit in the series will convert slab counters to bytes), it's not gonna work: value in bytes can easily exceed s8 without exceeding the threshold converted to bytes. So to avoid overfilling per-cpu caches and breaking vmstats correctness, let's use s32 instead. This doesn't affect per-zone statistics. There are no plans to use zone-level byte-sized counters, so no reasons to change anything. Signed-off-by: Roman Gushchin --- include/linux/mmzone.h | 2 +- mm/vmstat.c | 16 ++++++++-------- 2 files changed, 9 insertions(+), 9 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 462f6873905a..1c5eafd925e7 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -360,7 +360,7 @@ struct per_cpu_pageset { struct per_cpu_nodestat { s8 stat_threshold; - s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS]; + s32 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS]; }; #endif /* !__GENERATING_BOUNDS.H */ diff --git a/mm/vmstat.c b/mm/vmstat.c index 78d53378db99..6242129939dd 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -337,7 +337,7 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item, long delta) { struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats; - s8 __percpu *p = pcp->vm_node_stat_diff + item; + s32 __percpu *p = pcp->vm_node_stat_diff + item; long x; long t; @@ -395,13 +395,13 @@ void __inc_zone_state(struct zone *zone, enum zone_stat_item item) void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item) { struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats; - s8 __percpu *p = pcp->vm_node_stat_diff + item; - s8 v, t; + s32 __percpu *p = pcp->vm_node_stat_diff + item; + s32 v, t; v = __this_cpu_inc_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v > t)) { - s8 overstep = t >> 1; + s32 overstep = t >> 1; node_page_state_add(v + overstep, pgdat, item); __this_cpu_write(*p, -overstep); @@ -439,13 +439,13 @@ void __dec_zone_state(struct zone *zone, enum zone_stat_item item) void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item) { struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats; - s8 __percpu *p = pcp->vm_node_stat_diff + item; - s8 v, t; + s32 __percpu *p = pcp->vm_node_stat_diff + item; + s32 v, t; v = __this_cpu_dec_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v < - t)) { - s8 overstep = t >> 1; + s32 overstep = t >> 1; node_page_state_add(v - overstep, pgdat, item); __this_cpu_write(*p, overstep); @@ -538,7 +538,7 @@ 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 = pgdat->per_cpu_nodestats; - s8 __percpu *p = pcp->vm_node_stat_diff + item; + s32 __percpu *p = pcp->vm_node_stat_diff + item; long o, n, t, z; do { -- 2.24.1