• Linxu Fang's avatar
    mem-hotplug: fix node spanned pages when we have a node with only ZONE_MOVABLE · 27d8fa82
    Linxu Fang authored
    [ Upstream commit 299c83dce9ea3a79bb4b5511d2cb996b6b8e5111 ]
    
    342332e6 ("mm/page_alloc.c: introduce kernelcore=mirror option") and
    later patches rewrote the calculation of node spanned pages.
    
    e506b996 ("mem-hotplug: fix node spanned pages when we have a movable
    node"), but the current code still has problems,
    
    When we have a node with only zone_movable and the node id is not zero,
    the size of node spanned pages is double added.
    
    That's because we have an empty normal zone, and zone_start_pfn or
    zone_end_pfn is not between arch_zone_lowest_possible_pfn and
    arch_zone_highest_possible_pfn, so we need to use clamp to constrain the
    range just like the commit <96e907d1> (bootmem: Reimplement
    __absent_pages_in_range() using for_each_mem_pfn_range()).
    
    e.g.
    Zone ranges:
      DMA      [mem 0x0000000000001000-0x0000000000ffffff]
      DMA32    [mem 0x0000000001000000-0x00000000ffffffff]
      Normal   [mem 0x0000000100000000-0x000000023fffffff]
    Movable zone start for each node
      Node 0: 0x0000000100000000
      Node 1: 0x0000000140000000
    Early memory node ranges
      node   0: [mem 0x0000000000001000-0x000000000009efff]
      node   0: [mem 0x0000000000100000-0x00000000bffdffff]
      node   0: [mem 0x0000000100000000-0x000000013fffffff]
      node   1: [mem 0x0000000140000000-0x000000023fffffff]
    
    node 0 DMA	spanned:0xfff   present:0xf9e   absent:0x61
    node 0 DMA32	spanned:0xff000 present:0xbefe0	absent:0x40020
    node 0 Normal	spanned:0	present:0	absent:0
    node 0 Movable	spanned:0x40000 present:0x40000 absent:0
    On node 0 totalpages(node_present_pages): 1048446
    node_spanned_pages:1310719
    node 1 DMA	spanned:0	    present:0		absent:0
    node 1 DMA32	spanned:0	    present:0		absent:0
    node 1 Normal	spanned:0x100000    present:0x100000	absent:0
    node 1 Movable	spanned:0x100000    present:0x100000	absent:0
    On node 1 totalpages(node_present_pages): 2097152
    node_spanned_pages:2097152
    Memory: 6967796K/12582392K available (16388K kernel code, 3686K rwdata,
    4468K rodata, 2160K init, 10444K bss, 5614596K reserved, 0K
    cma-reserved)
    
    It shows that the current memory of node 1 is double added.
    After this patch, the problem is fixed.
    
    node 0 DMA	spanned:0xfff   present:0xf9e   absent:0x61
    node 0 DMA32	spanned:0xff000 present:0xbefe0	absent:0x40020
    node 0 Normal	spanned:0	present:0	absent:0
    node 0 Movable	spanned:0x40000 present:0x40000 absent:0
    On node 0 totalpages(node_present_pages): 1048446
    node_spanned_pages:1310719
    node 1 DMA	spanned:0	    present:0		absent:0
    node 1 DMA32	spanned:0	    present:0		absent:0
    node 1 Normal	spanned:0	    present:0		absent:0
    node 1 Movable	spanned:0x100000    present:0x100000	absent:0
    On node 1 totalpages(node_present_pages): 1048576
    node_spanned_pages:1048576
    memory: 6967796K/8388088K available (16388K kernel code, 3686K rwdata,
    4468K rodata, 2160K init, 10444K bss, 1420292K reserved, 0K
    cma-reserved)
    
    Link: http://lkml.kernel.org/r/1554178276-10372-1-git-send-email-fanglinxu@huawei.comSigned-off-by: 's avatarLinxu Fang <fanglinxu@huawei.com>
    Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
    Cc: Xishi Qiu <qiuxishi@huawei.com>
    Cc: Michal Hocko <mhocko@suse.com>
    Cc: Vlastimil Babka <vbabka@suse.cz>
    Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
    Cc: Oscar Salvador <osalvador@suse.de>
    Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: 's avatarSasha Levin <sashal@kernel.org>
    27d8fa82
page_alloc.c 211 KB