From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id C4F8F6B0253 for ; Mon, 2 Jan 2017 10:31:08 -0500 (EST) Received: by mail-wm0-f72.google.com with SMTP id s63so75895008wms.7 for ; Mon, 02 Jan 2017 07:31:08 -0800 (PST) Received: from mail-wm0-f68.google.com (mail-wm0-f68.google.com. [74.125.82.68]) by mx.google.com with ESMTPS id e138si69940777wmf.124.2017.01.02.07.31.07 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Jan 2017 07:31:07 -0800 (PST) Received: by mail-wm0-f68.google.com with SMTP id u144so82529664wmu.0 for ; Mon, 02 Jan 2017 07:31:07 -0800 (PST) From: Michal Hocko Subject: [PATCH 1/2] mm: fix remote numa hits statistics Date: Mon, 2 Jan 2017 16:30:56 +0100 Message-Id: <20170102153057.9451-2-mhocko@kernel.org> In-Reply-To: <20170102153057.9451-1-mhocko@kernel.org> References: <20170102153057.9451-1-mhocko@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Mel Gorman , Vlastimil Babka , Jia He , Andi Kleen , linux-mm@kvack.org, LKML , Michal Hocko From: Michal Hocko Jia He has noticed that b9f00e147f27 ("mm, page_alloc: reduce branches in zone_statistics") has an unintentional side effect that remote node allocation requests are accounted as NUMA_MISS rathat than NUMA_HIT and NUMA_OTHER if such a request doesn't use __GFP_OTHER_NODE. There are many of these potentially because the flag is used very rarely while we have many users of __alloc_pages_node. Fix this by simply ignoring __GFP_OTHER_NODE (it can be removed in a follow up patch) and treat all allocations that were satisfied from the preferred zone's node as NUMA_HITS because this is the same node we requested the allocation from in most cases. If this is not the local node then we just account it as NUMA_OTHER rather than NUMA_LOCAL. One downsize would be that an allocation request for a node which is outside of the mempolicy nodemask would be reported as a hit which is a bit weird but that was the case before b9f00e147f27 already. Reported-by: Jia He Fixes: b9f00e147f27 ("mm, page_alloc: reduce branches in zone_statistics") Acked-by: Mel Gorman Reviewed-by: Vlastimil Babka # with cbmc[1] superpowers Signed-off-by: Michal Hocko [1] http://paulmck.livejournal.com/38997.html --- mm/page_alloc.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f6d5b73e1d7c..e2a44950a685 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2583,30 +2583,23 @@ int __isolate_free_page(struct page *page, unsigned int order) * Update NUMA hit/miss statistics * * Must be called with interrupts disabled. - * - * When __GFP_OTHER_NODE is set assume the node of the preferred - * zone is the local node. This is useful for daemons who allocate - * memory on behalf of other processes. */ static inline void zone_statistics(struct zone *preferred_zone, struct zone *z, gfp_t flags) { #ifdef CONFIG_NUMA - int local_nid = numa_node_id(); enum zone_stat_item local_stat = NUMA_LOCAL; - if (unlikely(flags & __GFP_OTHER_NODE)) { + if (z->node != numa_node_id()) local_stat = NUMA_OTHER; - local_nid = preferred_zone->node; - } - if (z->node == local_nid) { + if (z->node == preferred_zone->node) __inc_zone_state(z, NUMA_HIT); - __inc_zone_state(z, local_stat); - } else { + else { __inc_zone_state(z, NUMA_MISS); __inc_zone_state(preferred_zone, NUMA_FOREIGN); } + __inc_zone_state(z, local_stat); #endif } -- 2.11.0 -- 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