From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: [patch 042/115] mm: avoid taking zone lock in pagetypeinfo_showmixed() Date: Mon, 10 Jul 2017 15:49:17 -0700 Message-ID: <20170710224917.c9L12dfHG%akpm@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.linuxfoundation.org ([140.211.169.12]:42782 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932151AbdGJWtY (ORCPT ); Mon, 10 Jul 2017 18:49:24 -0400 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: akpm@linux-foundation.org, bigeasy@linutronix.de, hannes@cmpxchg.org, iamjoonsoo.kim@lge.com, mgorman@techsingularity.net, mhocko@suse.com, minchan@kernel.org, mm-commits@vger.kernel.org, rientjes@google.com, sergey.senozhatsky@gmail.com, sudipm.mukherjee@gmail.com, torvalds@linux-foundation.org, vbabka@suse.cz, vinmenon@codeaurora.org, zhongjiang@huawei.com From: Vinayak Menon Subject: mm: avoid taking zone lock in pagetypeinfo_showmixed() pagetypeinfo_showmixedcount_print is found to take a lot of time to complete and it does this holding the zone lock and disabling interrupts. In some cases it is found to take more than a second (On a 2.4GHz,8Gb RAM,arm64 cpu). Avoid taking the zone lock similar to what is done by read_page_owner, which means possibility of inaccurate results. Link: http://lkml.kernel.org/r/1498045643-12257-1-git-send-email-vinmenon@codeaurora.org Signed-off-by: Vinayak Menon Acked-by: Vlastimil Babka Cc: Joonsoo Kim Cc: zhongjiang Cc: Sergey Senozhatsky Cc: Sudip Mukherjee Cc: Johannes Weiner Cc: Mel Gorman Cc: Michal Hocko Cc: Sebastian Andrzej Siewior Cc: David Rientjes Cc: Minchan Kim Signed-off-by: Andrew Morton --- mm/page_owner.c | 6 +++++- mm/vmstat.c | 24 ++++++++++++++---------- 2 files changed, 19 insertions(+), 11 deletions(-) diff -puN mm/page_owner.c~mm-avoid-taking-zone-lock-in-pagetypeinfo_showmixed mm/page_owner.c --- a/mm/page_owner.c~mm-avoid-taking-zone-lock-in-pagetypeinfo_showmixed +++ a/mm/page_owner.c @@ -281,7 +281,11 @@ void pagetypeinfo_showmixedcount_print(s continue; if (PageBuddy(page)) { - pfn += (1UL << page_order(page)) - 1; + unsigned long freepage_order; + + freepage_order = page_order_unsafe(page); + if (freepage_order < MAX_ORDER) + pfn += (1UL << freepage_order) - 1; continue; } diff -puN mm/vmstat.c~mm-avoid-taking-zone-lock-in-pagetypeinfo_showmixed mm/vmstat.c --- a/mm/vmstat.c~mm-avoid-taking-zone-lock-in-pagetypeinfo_showmixed +++ a/mm/vmstat.c @@ -1130,7 +1130,7 @@ static void frag_stop(struct seq_file *m * If @assert_populated is true, only use callback for zones that are populated. */ static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat, - bool assert_populated, + bool assert_populated, bool nolock, void (*print)(struct seq_file *m, pg_data_t *, struct zone *)) { struct zone *zone; @@ -1141,9 +1141,11 @@ static void walk_zones_in_node(struct se if (assert_populated && !populated_zone(zone)) continue; - spin_lock_irqsave(&zone->lock, flags); + if (!nolock) + spin_lock_irqsave(&zone->lock, flags); print(m, pgdat, zone); - spin_unlock_irqrestore(&zone->lock, flags); + if (!nolock) + spin_unlock_irqrestore(&zone->lock, flags); } } #endif @@ -1166,7 +1168,7 @@ static void frag_show_print(struct seq_f static int frag_show(struct seq_file *m, void *arg) { pg_data_t *pgdat = (pg_data_t *)arg; - walk_zones_in_node(m, pgdat, true, frag_show_print); + walk_zones_in_node(m, pgdat, true, false, frag_show_print); return 0; } @@ -1207,7 +1209,7 @@ static int pagetypeinfo_showfree(struct seq_printf(m, "%6d ", order); seq_putc(m, '\n'); - walk_zones_in_node(m, pgdat, true, pagetypeinfo_showfree_print); + walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print); return 0; } @@ -1258,7 +1260,8 @@ static int pagetypeinfo_showblockcount(s for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) seq_printf(m, "%12s ", migratetype_names[mtype]); seq_putc(m, '\n'); - walk_zones_in_node(m, pgdat, true, pagetypeinfo_showblockcount_print); + walk_zones_in_node(m, pgdat, true, false, + pagetypeinfo_showblockcount_print); return 0; } @@ -1284,7 +1287,8 @@ static void pagetypeinfo_showmixedcount( seq_printf(m, "%12s ", migratetype_names[mtype]); seq_putc(m, '\n'); - walk_zones_in_node(m, pgdat, true, pagetypeinfo_showmixedcount_print); + walk_zones_in_node(m, pgdat, true, true, + pagetypeinfo_showmixedcount_print); #endif /* CONFIG_PAGE_OWNER */ } @@ -1446,7 +1450,7 @@ static void zoneinfo_show_print(struct s static int zoneinfo_show(struct seq_file *m, void *arg) { pg_data_t *pgdat = (pg_data_t *)arg; - walk_zones_in_node(m, pgdat, false, zoneinfo_show_print); + walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print); return 0; } @@ -1852,7 +1856,7 @@ static int unusable_show(struct seq_file if (!node_state(pgdat->node_id, N_MEMORY)) return 0; - walk_zones_in_node(m, pgdat, true, unusable_show_print); + walk_zones_in_node(m, pgdat, true, false, unusable_show_print); return 0; } @@ -1904,7 +1908,7 @@ static int extfrag_show(struct seq_file { pg_data_t *pgdat = (pg_data_t *)arg; - walk_zones_in_node(m, pgdat, true, extfrag_show_print); + walk_zones_in_node(m, pgdat, true, false, extfrag_show_print); return 0; } _