From: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx> Subject: mm/memory-hotplug: fix lowmem count overflow when offline pages Logic 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@xxxxxxx: fix CONFIG_HIGHMEM=n build] Signed-off-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx> Reviewed-by: Michal Hocko <mhocko@xxxxxxx> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> [2.6.24+] Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 4 ++++ 1 file changed, 4 insertions(+) diff -puN mm/page_alloc.c~mm-memory-hotplug-fix-lowmem-count-overflow-when-offline-pages mm/page_alloc.c --- a/mm/page_alloc.c~mm-memory-hotplug-fix-lowmem-count-overflow-when-offline-pages +++ a/mm/page_alloc.c @@ -6185,6 +6185,10 @@ __offline_isolated_pages(unsigned long s list_del(&page->lru); rmv_page_order(page); zone->free_area[order].nr_free--; +#ifdef CONFIG_HIGHMEM + if (PageHighMem(page)) + totalhigh_pages -= 1 << order; +#endif for (i = 0; i < (1 << order); i++) SetPageReserved((page+i)); pfn += (1 << order); _ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html