1. 28 Jun, 2015 10 commits
  2. 22 Jun, 2015 1 commit
    • Mel Gorman's avatar
      sched, numa: Do not hint for NUMA balancing on VM_MIXEDMAP mappings · 90b934b1
      Mel Gorman authored
      commit 8e76d4ee upstream.
      
      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: default avatarMel Gorman <mgorman@suse.de>
      Reported-by: default avatarJovi 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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      [jovi: Backported to 3.18: adjust context]
      Signed-off-by: default avatarJovi Zhangwei <jovi@cloudflare.com>
      Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      90b934b1
  3. 15 Jun, 2015 29 commits