From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752432AbdKVWZS (ORCPT ); Wed, 22 Nov 2017 17:25:18 -0500 Received: from omzsmtpe01.verizonbusiness.com ([199.249.25.210]:13694 "EHLO omzsmtpe01.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752322AbdKVWZG (ORCPT ); Wed, 22 Nov 2017 17:25:06 -0500 From: alexander.levin@verizon.com Cc: Michal Hocko , Johannes Weiner , Joonsoo Kim , Taku Izumi , Andrew Morton , Linus Torvalds , alexander.levin@verizon.com X-Host: endeavour.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.9 18/54] mm: fix remote numa hits statistics Thread-Topic: [PATCH AUTOSEL for 4.9 18/54] mm: fix remote numa hits statistics Thread-Index: AQHTY+CV3k4yGLh7jkuQpgl5dXjMoQ== Date: Wed, 22 Nov 2017 22:23:55 +0000 Message-ID: <20171122222344.19782-18-alexander.levin@verizon.com> References: <20171122222344.19782-1-alexander.levin@verizon.com> In-Reply-To: <20171122222344.19782-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vAMMPOS9022836 From: Michal Hocko [ Upstream commit 2df26639e708a88dcc22171949da638a9998f3bc ] Jia He has noticed that commit 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. Fixes: b9f00e147f27 ("mm, page_alloc: reduce branches in zone_statistics") Link: http://lkml.kernel.org/r/20170102153057.9451-2-mhocko@kernel.org Signed-off-by: Michal Hocko Reported-by: Jia He Reviewed-by: Vlastimil Babka # with cbmc[1] superpowers Acked-by: Mel Gorman Cc: Johannes Weiner Cc: Joonsoo Kim Cc: Taku Izumi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- 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 7064aae8ded7..bed0fa6125f3 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