From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f200.google.com (mail-wj0-f200.google.com [209.85.210.200]) by kanga.kvack.org (Postfix) with ESMTP id BFC196B0381 for ; Wed, 21 Dec 2016 03:06:59 -0500 (EST) Received: by mail-wj0-f200.google.com with SMTP id gl16so6302939wjc.5 for ; Wed, 21 Dec 2016 00:06:59 -0800 (PST) Received: from mail-wj0-f194.google.com (mail-wj0-f194.google.com. [209.85.210.194]) by mx.google.com with ESMTPS id g142si22833761wmg.53.2016.12.21.00.06.58 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Dec 2016 00:06:58 -0800 (PST) Received: by mail-wj0-f194.google.com with SMTP id j10so30919197wjb.3 for ; Wed, 21 Dec 2016 00:06:58 -0800 (PST) From: Michal Hocko Subject: [PATCH 1/2] mm: fix remote numa hits statistics Date: Wed, 21 Dec 2016 09:06:52 +0100 Message-Id: <20161221080653.29437-1-mhocko@kernel.org> In-Reply-To: <20161221075711.GF16502@dhcp22.suse.cz> References: <20161221075711.GF16502@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: Mel Gorman , Vlastimil Babka , Andrew Morton , Joonsoo Kim , Jia He , Taku Izumi , Johannes Weiner , 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") Signed-off-by: Michal Hocko --- mm/page_alloc.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f6d5b73e1d7c..506946a902c5 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2583,25 +2583,17 @@ 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)) { - local_stat = NUMA_OTHER; - local_nid = preferred_zone->node; - } + if (z->node == preferred_zone->node) { + enum zone_stat_item local_stat = NUMA_LOCAL; - if (z->node == local_nid) { __inc_zone_state(z, NUMA_HIT); + if (z->node != numa_node_id()) + local_stat = NUMA_OTHER; __inc_zone_state(z, local_stat); } else { __inc_zone_state(z, NUMA_MISS); -- 2.10.2 -- 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