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authorMel Gorman <mgorman@suse.de>2015-06-10 18:15:00 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2015-06-10 23:43:43 (GMT)
commit8e76d4eecf7afeec9328e21cd5880e281838d0d6 (patch)
tree90d2bdbbb5847ae9c25fd0f59d1bc09010b5aea4 /kernel/kcmp.c
parent02f7b4145da113683ad64c74bf64605e16b71789 (diff)
downloadlinux-8e76d4eecf7afeec9328e21cd5880e281838d0d6.tar.xz
sched, numa: do not hint for NUMA balancing on VM_MIXEDMAP mappings
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. Signed-off-by: Mel Gorman <mgorman@suse.de> Reported-by: Jovi Zhangwei <jovi@cloudflare.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/kcmp.c')
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