From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id E4BF46B0253 for ; Tue, 19 Dec 2017 01:41:38 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id i14so12151520pgf.13 for ; Mon, 18 Dec 2017 22:41:38 -0800 (PST) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTPS id k91si10570919pld.115.2017.12.18.22.41.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 18 Dec 2017 22:41:37 -0800 (PST) From: Kemi Wang Subject: [PATCH v2 2/5] mm: Extends local cpu counter vm_diff_nodestat from s8 to s16 Date: Tue, 19 Dec 2017 14:39:23 +0800 Message-Id: <1513665566-4465-3-git-send-email-kemi.wang@intel.com> In-Reply-To: <1513665566-4465-1-git-send-email-kemi.wang@intel.com> References: <1513665566-4465-1-git-send-email-kemi.wang@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Greg Kroah-Hartman , Andrew Morton , Michal Hocko , Vlastimil Babka , Mel Gorman , Johannes Weiner , Christopher Lameter , YASUAKI ISHIMATSU , Andrey Ryabinin , Nikolay Borisov , Pavel Tatashin , David Rientjes , Sebastian Andrzej Siewior Cc: Dave , Andi Kleen , Tim Chen , Jesper Dangaard Brouer , Ying Huang , Aaron Lu , Aubrey Li , Kemi Wang , Linux MM , Linux Kernel The type s8 used for vm_diff_nodestat[] as local cpu counters has the limitation of global counters update frequency, especially for those monotone increasing type of counters like NUMA counters with more and more cpus/nodes. This patch extends the type of vm_diff_nodestat from s8 to s16 without any functionality change. before after sizeof(struct per_cpu_nodestat) 28 68 Signed-off-by: Kemi Wang --- include/linux/mmzone.h | 4 ++-- mm/vmstat.c | 16 ++++++++-------- 2 files changed, 10 insertions(+), 10 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index c06d880..2da6b6f 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -289,8 +289,8 @@ struct per_cpu_pageset { }; struct per_cpu_nodestat { - s8 stat_threshold; - s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS]; + s16 stat_threshold; + s16 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS]; }; #endif /* !__GENERATING_BOUNDS.H */ diff --git a/mm/vmstat.c b/mm/vmstat.c index 1dd12ae..9c681cc 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -332,7 +332,7 @@ 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; + s16 __percpu *p = pcp->vm_node_stat_diff + item; long x; long t; @@ -390,13 +390,13 @@ 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; + s16 __percpu *p = pcp->vm_node_stat_diff + item; + s16 v, t; v = __this_cpu_inc_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v > t)) { - s8 overstep = t >> 1; + s16 overstep = t >> 1; node_page_state_add(v + overstep, pgdat, item); __this_cpu_write(*p, -overstep); @@ -434,13 +434,13 @@ 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; + s16 __percpu *p = pcp->vm_node_stat_diff + item; + s16 v, t; v = __this_cpu_dec_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v < - t)) { - s8 overstep = t >> 1; + s16 overstep = t >> 1; node_page_state_add(v - overstep, pgdat, item); __this_cpu_write(*p, overstep); @@ -533,7 +533,7 @@ 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; + s16 __percpu *p = pcp->vm_node_stat_diff + item; long o, n, t, z; do { -- 2.7.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org