• Yinghai Lu's avatar
    x86, ACPI, mm: Revert movablemem_map support · 20e6926d
    Yinghai Lu authored
    Tim found:
    
      WARNING: at arch/x86/kernel/smpboot.c:324 topology_sane.isra.2+0x6f/0x80()
      Hardware name: S2600CP
      sched: CPU #1's llc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency.
      smpboot: Booting Node   1, Processors  #1
      Modules linked in:
      Pid: 0, comm: swapper/1 Not tainted 3.9.0-0-generic #1
      Call Trace:
        set_cpu_sibling_map+0x279/0x449
        start_secondary+0x11d/0x1e5
    
    Don Morris reproduced on a HP z620 workstation, and bisected it to
    commit e8d19552 ("acpi, memory-hotplug: parse SRAT before memblock
    is ready")
    
    It turns out movable_map has some problems, and it breaks several things
    
    1. numa_init is called several times, NOT just for srat. so those
    	nodes_clear(numa_nodes_parsed)
    	memset(&numa_meminfo, 0, sizeof(numa_meminfo))
       can not be just removed.  Need to consider sequence is: numaq, srat, amd, dummy.
       and make fall back path working.
    
    2. simply split acpi_numa_init to early_parse_srat.
       a. that early_parse_srat is NOT called for ia64, so you break ia64.
       b.  for (i = 0; i < MAX_LOCAL_APIC; i++)
    	     set_apicid_to_node(i, NUMA_NO_NODE)
         still left in numa_init. So it will just clear result from early_parse_srat.
         it should be moved before that....
       c.  it breaks ACPI_TABLE_OVERIDE...as the acpi table scan is moved
           early before override from INITRD is settled.
    
    3. that patch TITLE is total misleading, there is NO x86 in the title,
       but it changes critical x86 code. It caused x86 guys did not
       pay attention to find the problem early. Those patches really should
       be routed via tip/x86/mm.
    
    4. after that commit, following range can not use movable ram:
      a. real_mode code.... well..funny, legacy Node0 [0,1M) could be hot-removed?
      b. initrd... it will be freed after booting, so it could be on movable...
      c. crashkernel for kdump...: looks like we can not put kdump kernel above 4G
    	anymore.
      d. init_mem_mapping: can not put page table high anymore.
      e. initmem_init: vmemmap can not be high local node anymore. That is
         not good.
    
    If node is hotplugable, the mem related range like page table and
    vmemmap could be on the that node without problem and should be on that
    node.
    
    We have workaround patch that could fix some problems, but some can not
    be fixed.
    
    So just remove that offending commit and related ones including:
    
     f7210e6c ("mm/memblock.c: use CONFIG_HAVE_MEMBLOCK_NODE_MAP to
        protect movablecore_map in memblock_overlaps_region().")
    
     01a178a9 ("acpi, memory-hotplug: support getting hotplug info from
        SRAT")
    
     27168d38 ("acpi, memory-hotplug: extend movablemem_map ranges to
        the end of node")
    
     e8d19552 ("acpi, memory-hotplug: parse SRAT before memblock is
        ready")
    
     fb06bc8e ("page_alloc: bootmem limit with movablecore_map")
    
     42f47e27 ("page_alloc: make movablemem_map have higher priority")
    
     6981ec31 ("page_alloc: introduce zone_movable_limit[] to keep
        movable limit for nodes")
    
     34b71f1e ("page_alloc: add movable_memmap kernel parameter")
    
     4d59a751
    
     ("x86: get pg_data_t's memory from other node")
    
    Later we should have patches that will make sure kernel put page table
    and vmemmap on local node ram instead of push them down to node0.  Also
    need to find way to put other kernel used ram to local node ram.
    
    Reported-by: default avatarTim Gardner <tim.gardner@canonical.com>
    Reported-by: default avatarDon Morris <don.morris@hp.com>
    Bisected-by: default avatarDon Morris <don.morris@hp.com>
    Tested-by: default avatarDon Morris <don.morris@hp.com>
    Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
    Cc: Tony Luck <tony.luck@intel.com>
    Cc: Thomas Renninger <trenn@suse.de>
    Cc: Tejun Heo <tj@kernel.org>
    Cc: Tang Chen <tangchen@cn.fujitsu.com>
    Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    20e6926d