The commit is pushed to "branch-rh7-3.10.0-693.21.1.vz7.47.x-ovz" and will 
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.21.1.vz7.47.1
------>
commit 70b9d7d5791d062e18e47565f463ad6face86623
Author: Daniel Vacek <[email protected]>
Date:   Fri Apr 27 13:00:55 2018 +0300

    ms/Revert "mm: page_alloc: skip over regions of invalid pfns where possible"
    
    This reverts commit b92df1de5d28 ("mm: page_alloc: skip over regions of
    invalid pfns where possible").  The commit is meant to be a boot init
    speed up skipping the loop in memmap_init_zone() for invalid pfns.
    
    But given some specific memory mapping on x86_64 (or more generally
    theoretically anywhere but on arm with CONFIG_HAVE_ARCH_PFN_VALID) the
    implementation also skips valid pfns which is plain wrong and causes
    'kernel BUG at mm/page_alloc.c:1389!'
    
      crash> log | grep -e BUG -e RIP -e Call.Trace -e move_freepages_block -e 
rmqueue -e freelist -A1
      kernel BUG at mm/page_alloc.c:1389!
      invalid opcode: 0000 [#1] SMP
      --
      RIP: 0010: move_freepages+0x15e/0x160
      --
      Call Trace:
        move_freepages_block+0x73/0x80
        __rmqueue+0x263/0x460
        get_page_from_freelist+0x7e1/0x9e0
        __alloc_pages_nodemask+0x176/0x420
      --
    
      crash> page_init_bug -v | grep RAM
      <struct resource 0xffff88067fffd2f8>          1000 -        9bfff       
System RAM (620.00 KiB)
      <struct resource 0xffff88067fffd3a0>        100000 -     430bffff       
System RAM (  1.05 GiB = 1071.75 MiB = 1097472.00 KiB)
      <struct resource 0xffff88067fffd410>      4b0c8000 -     4bf9cfff       
System RAM ( 14.83 MiB = 15188.00 KiB)
      <struct resource 0xffff88067fffd480>      4bfac000 -     646b1fff       
System RAM (391.02 MiB = 400408.00 KiB)
      <struct resource 0xffff88067fffd560>      7b788000 -     7b7fffff       
System RAM (480.00 KiB)
      <struct resource 0xffff88067fffd640>     100000000 -    67fffffff       
System RAM ( 22.00 GiB)
    
      crash> page_init_bug | head -6
      <struct resource 0xffff88067fffd560>      7b788000 -     7b7fffff       
System RAM (480.00 KiB)
      <struct page 0xffffea0001ede200>   1fffff00000000  0 <struct pglist_data 
0xffff88047ffd9000> 1 <struct zone 0xffff88047ffd9800> DMA32          4096    
1048575
      <struct page 0xffffea0001ede200>       505736 505344 <struct page 
0xffffea0001ed8000> 505855 <struct page 0xffffea0001edffc0>
      <struct page 0xffffea0001ed8000>                0  0 <struct pglist_data 
0xffff88047ffd9000> 0 <struct zone 0xffff88047ffd9000> DMA               1      
 4095
      <struct page 0xffffea0001edffc0>   1fffff00000400  0 <struct pglist_data 
0xffff88047ffd9000> 1 <struct zone 0xffff88047ffd9800> DMA32          4096    
1048575
      BUG, zones differ!
    
      crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b787000 7b788000
            PAGE        PHYSICAL      MAPPING       INDEX CNT FLAGS
      ffffea0001e00000  78000000                0        0  0 0
      ffffea0001ed7fc0  7b5ff000                0        0  0 0
      ffffea0001ed8000  7b600000                0        0  0 0       <<<<
      ffffea0001ede1c0  7b787000                0        0  0 0
      ffffea0001ede200  7b788000                0        0  1 1fffff00000000
    
    Link: http://lkml.kernel.org/r/[email protected]
    Fixes: b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns 
where possible")
    Signed-off-by: Daniel Vacek <[email protected]>
    Acked-by: Ard Biesheuvel <[email protected]>
    Acked-by: Michal Hocko <[email protected]>
    Reviewed-by: Andrew Morton <[email protected]>
    Cc: Vlastimil Babka <[email protected]>
    Cc: Mel Gorman <[email protected]>
    Cc: Pavel Tatashin <[email protected]>
    Cc: Paul Burton <[email protected]>
    Cc: <[email protected]>
    Signed-off-by: Andrew Morton <[email protected]>
    Signed-off-by: Linus Torvalds <[email protected]>
    
    Just an additional fix while investigating:
    https://jira.sw.ru/browse/PSBM-83746
    
    (cherry picked from commit f59f1caf72ba00d519c793c3deb32cd3be32edc2)
    Signed-off-by: Konstantin Khorenko <[email protected]>
---
 include/linux/memblock.h |  1 -
 mm/memblock.c            | 28 ----------------------------
 mm/page_alloc.c          | 11 +----------
 3 files changed, 1 insertion(+), 39 deletions(-)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 5a439c937c3c..dad171f37f66 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -186,7 +186,6 @@ int memblock_search_pfn_nid(unsigned long pfn, unsigned 
long *start_pfn,
                            unsigned long  *end_pfn);
 void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn,
                          unsigned long *out_end_pfn, int *out_nid);
-unsigned long memblock_next_valid_pfn(unsigned long pfn, unsigned long 
max_pfn);
 
 /**
  * for_each_mem_pfn_range - early memory pfn range iterator
diff --git a/mm/memblock.c b/mm/memblock.c
index fbc8071d9f43..e08475cd1c0a 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1061,34 +1061,6 @@ void __init_memblock __next_mem_pfn_range(int *idx, int 
nid,
                *out_nid = r->nid;
 }
 
-unsigned long __init_memblock memblock_next_valid_pfn(unsigned long pfn,
-                                                     unsigned long max_pfn)
-{
-       struct memblock_type *type = &memblock.memory;
-       unsigned int right = type->cnt;
-       unsigned int mid, left = 0;
-       phys_addr_t addr = PFN_PHYS(pfn + 1);
-
-       do {
-               mid = (right + left) / 2;
-
-               if (addr < type->regions[mid].base)
-                       right = mid;
-               else if (addr >= (type->regions[mid].base +
-                                 type->regions[mid].size))
-                       left = mid + 1;
-               else {
-                       /* addr is within the region, so pfn + 1 is valid */
-                       return min(pfn + 1, max_pfn);
-               }
-       } while (left < right);
-
-       if (right == type->cnt)
-               return max_pfn;
-       else
-               return min(PHYS_PFN(type->regions[right].base), max_pfn);
-}
-
 /**
  * memblock_set_node - set node ID on memblock regions
  * @base: base of area to set node ID for
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7fa5f026434c..e658abb6ff10 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4717,17 +4717,8 @@ void __meminit memmap_init_zone(unsigned long size, int 
nid, unsigned long zone,
                if (context != MEMMAP_EARLY)
                        goto not_early;
 
-               if (!early_pfn_valid(pfn)) {
-#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
-                       /*
-                        * Skip to the pfn preceding the next valid one (or
-                        * end_pfn), such that we hit a valid pfn (or end_pfn)
-                        * on our next iteration of the loop.
-                        */
-                       pfn = memblock_next_valid_pfn(pfn, end_pfn) - 1;
-#endif
+               if (!early_pfn_valid(pfn))
                        continue;
-               }
                if (!early_pfn_in_nid(pfn, nid))
                        continue;
                if (!update_defer_init(pgdat, pfn, size, end_pfn,
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