From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f175.google.com (mail-lb0-f175.google.com [209.85.217.175]) by kanga.kvack.org (Postfix) with ESMTP id BAF3B6B0032 for ; Mon, 8 Jun 2015 10:08:59 -0400 (EDT) Received: by lbcue7 with SMTP id ue7so81571072lbc.0 for ; Mon, 08 Jun 2015 07:08:59 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id ev4si5330614wjc.204.2015.06.08.07.08.57 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 08 Jun 2015 07:08:58 -0700 (PDT) Date: Mon, 8 Jun 2015 15:08:54 +0100 From: Mel Gorman Subject: [PATCH] sched, numa: Do not hint for NUMA balancing on VM_MIXEDMAP mappings Message-ID: <20150608140854.GP26425@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: Jovi Zhangwei , linux-kernel@vger.kernel.org, linux-mm@kvack.org Jovi Zhangwei reported the following problem Below kernel vm bug can be triggered by tcpdump which mmaped a lot of pages with GFP_COMP flag. [Mon May 25 05:29:33 2015] page:ffffea0015414000 count:66 mapcount:1 mapping: (null) index:0x0 [Mon May 25 05:29:33 2015] flags: 0x20047580004000(head) [Mon May 25 05:29:33 2015] page dumped because: VM_BUG_ON_PAGE(compound_order(page) && !PageTransHuge(page)) [Mon May 25 05:29:33 2015] ------------[ cut here ]------------ [Mon May 25 05:29:33 2015] kernel BUG at mm/migrate.c:1661! [Mon May 25 05:29:33 2015] invalid opcode: 0000 [#1] SMP In this case it was triggered by running tcpdump but it's not necessary reproducible on all systems. sudo tcpdump -i bond0.100 'tcp port 4242' -c 100000000000 -w 4242.pcap Compound pages cannot be migrated and it was not expected that such pages be marked for NUMA balancing. This did not take into account that drivers such as net/packet/af_packet.c may insert compound pages into userspace with vm_insert_page. This patch tells the NUMA balancing protection scanner to skip all VM_MIXEDMAP mappings which avoids the possibility that compound pages are marked for migration. Cc: stable@vger.kernel.org Signed-off-by: Mel Gorman Reported-by: Jovi Zhangwei --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ffeaa4105e48..c2980e8733bc 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2181,7 +2181,7 @@ void task_numa_work(struct callback_head *work) } for (; vma; vma = vma->vm_next) { if (!vma_migratable(vma) || !vma_policy_mof(vma) || - is_vm_hugetlb_page(vma)) { + is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_MIXEDMAP)) { continue; } -- 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