From: Linxu Fang fanglinxu@huawei.com
[ Upstream commit 299c83dce9ea3a79bb4b5511d2cb996b6b8e5111 ]
342332e6a925 ("mm/page_alloc.c: introduce kernelcore=mirror option") and later patches rewrote the calculation of node spanned pages.
e506b99696a2 ("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 <96e907d13602> (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.... Signed-off-by: Linxu 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: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/page_alloc.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d59be95ba45cf..140acb4b69aae 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6182,13 +6182,15 @@ static unsigned long __init zone_spanned_pages_in_node(int nid, unsigned long *zone_end_pfn, unsigned long *ignored) { + unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type]; + unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type]; /* When hotadd a new node from cpu_up(), the node should be empty */ if (!node_start_pfn && !node_end_pfn) return 0;
/* Get the start and end of the zone */ - *zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type]; - *zone_end_pfn = arch_zone_highest_possible_pfn[zone_type]; + *zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high); + *zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high); adjust_zone_range_for_zone_movable(nid, zone_type, node_start_pfn, node_end_pfn, zone_start_pfn, zone_end_pfn);