git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 7f36e3e56db1ae75d1e157011b3cb2e0957f0a7e Mon Sep 17 00:00:00 2001
   2 From: Tang Chen <tangchen@cn.fujitsu.com>
   3 Date: Fri, 4 Sep 2015 15:42:32 -0700
   4 Subject: memory-hotplug: add hot-added memory ranges to memblock before allocate node_data for a node.
   5
   6 From: Tang Chen <tangchen@cn.fujitsu.com>
   7
   8 commit 7f36e3e56db1ae75d1e157011b3cb2e0957f0a7e upstream.
   9
  10 Commit f9126ab9241f ("memory-hotplug: fix wrong edge when hot add a new
  11 node") hot-added memory range to memblock, after creating pgdat for new
  12 node.
  13
  14 But there is a problem:
  15
  16   add_memory()
  17   |--> hotadd_new_pgdat()
  18        |--> free_area_init_node()
  19             |--> get_pfn_range_for_nid()
  20                  |--> find start_pfn and end_pfn in memblock
  21   |--> ......
  22   |--> memblock_add_node(start, size, nid)    --------    Here, just too late.
  23
  24 get_pfn_range_for_nid() will find that start_pfn and end_pfn are both 0.
  25 As a result, when adding memory, dmesg will give the following wrong
  26 message.
  27
  28   Initmem setup node 5 [mem 0x0000000000000000-0xffffffffffffffff]
  29   On node 5 totalpages: 0
  30   Built 5 zonelists in Node order, mobility grouping on.  Total pages: 32588823
  31   Policy zone: Normal
  32   init_memory_mapping: [mem 0x60000000000-0x607ffffffff]
  33
  34 The solution is simple, just add the memory range to memblock a little
  35 earlier, before hotadd_new_pgdat().
  36
  37 [akpm@linux-foundation.org: coding-style fixes]
  38 Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
  39 Cc: Xishi Qiu <qiuxishi@huawei.com>
  40 Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
  41 Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
  42 Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
  43 Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
  44 Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
  45 Cc: Vlastimil Babka <vbabka@suse.cz>
  46 Cc: Mel Gorman <mgorman@techsingularity.net>
  47 Cc: David Rientjes <rientjes@google.com>
  48 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  49 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  50 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  51
  52 ---
  53  mm/memory_hotplug.c |   10 +++++++++-
  54  1 file changed, 9 insertions(+), 1 deletion(-)
  55
  56 --- a/mm/memory_hotplug.c
  57 +++ b/mm/memory_hotplug.c
  58 @@ -1248,6 +1248,14 @@ int __ref add_memory(int nid, u64 start,
  59
  60         mem_hotplug_begin();
  61
  62 +       /*
  63 +        * Add new range to memblock so that when hotadd_new_pgdat() is called
  64 +        * to allocate new pgdat, get_pfn_range_for_nid() will be able to find
  65 +        * this new range and calculate total pages correctly.  The range will
  66 +        * be removed at hot-remove time.
  67 +        */
  68 +       memblock_add_node(start, size, nid);
  69 +
  70         new_node = !node_online(nid);
  71         if (new_node) {
  72                 pgdat = hotadd_new_pgdat(nid, start);
  73 @@ -1277,7 +1285,6 @@ int __ref add_memory(int nid, u64 start,
  74
  75         /* create new memmap entry */
  76         firmware_map_add_hotplug(start, start + size, "System RAM");
  77 -       memblock_add_node(start, size, nid);
  78
  79         goto out;
  80
  81 @@ -1286,6 +1293,7 @@ error:
  82         if (new_pgdat)
  83                 rollback_node_hotadd(nid, pgdat);
  84         release_memory_resource(res);
  85 +       memblock_remove(start, size);
  86
  87  out:
  88         mem_hotplug_done();