Commit cea27eb2 authored by Wanpeng Li's avatar Wanpeng Li Committed by Linus Torvalds

mm/memory-hotplug: fix lowmem count overflow when offline pages

The logic for the memory-remove code fails to correctly account the
Total High Memory when a memory block which contains High Memory is
offlined as shown in the example below.  The following patch fixes it.

Before logic memory remove:

MemTotal:        7603740 kB
MemFree:         6329612 kB
Buffers:           94352 kB
Cached:           872008 kB
SwapCached:            0 kB
Active:           626932 kB
Inactive:         519216 kB
Active(anon):     180776 kB
Inactive(anon):   222944 kB
Active(file):     446156 kB
Inactive(file):   296272 kB
Unevictable:           0 kB
Mlocked:               0 kB
HighTotal:       7294672 kB
HighFree:        5704696 kB
LowTotal:         309068 kB
LowFree:          624916 kB

After logic memory remove:

MemTotal:        7079452 kB
MemFree:         5805976 kB
Buffers:           94372 kB
Cached:           872000 kB
SwapCached:            0 kB
Active:           626936 kB
Inactive:         519236 kB
Active(anon):     180780 kB
Inactive(anon):   222944 kB
Active(file):     446156 kB
Inactive(file):   296292 kB
Unevictable:           0 kB
Mlocked:               0 kB
HighTotal:       7294672 kB
HighFree:        5181024 kB
LowTotal:       4294752076 kB
LowFree:          624952 kB

[mhocko@suse.cz: fix CONFIG_HIGHMEM=n build]
Signed-off-by: default avatarWanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>	[2.6.24+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4996eed8
...@@ -6185,6 +6185,10 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) ...@@ -6185,6 +6185,10 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
list_del(&page->lru); list_del(&page->lru);
rmv_page_order(page); rmv_page_order(page);
zone->free_area[order].nr_free--; zone->free_area[order].nr_free--;
#ifdef CONFIG_HIGHMEM
if (PageHighMem(page))
totalhigh_pages -= 1 << order;
#endif
for (i = 0; i < (1 << order); i++) for (i = 0; i < (1 << order); i++)
SetPageReserved((page+i)); SetPageReserved((page+i));
pfn += (1 << order); pfn += (1 << order);
......
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