| From cea27eb2a202959783f81254c48c250ddd80e129 Mon Sep 17 00:00:00 2001 |
| From: Wanpeng Li <liwanp@linux.vnet.ibm.com> |
| Date: Wed, 3 Jul 2013 15:02:40 -0700 |
| Subject: mm/memory-hotplug: fix lowmem count overflow when offline pages |
| |
| From: Wanpeng Li <liwanp@linux.vnet.ibm.com> |
| |
| commit cea27eb2a202959783f81254c48c250ddd80e129 upstream. |
| |
| 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: Wanpeng Li <liwanp@linux.vnet.ibm.com> |
| Reviewed-by: Michal Hocko <mhocko@suse.cz> |
| Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
| Cc: David Rientjes <rientjes@google.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| mm/page_alloc.c | 4 ++++ |
| 1 file changed, 4 insertions(+) |
| |
| --- a/mm/page_alloc.c |
| +++ b/mm/page_alloc.c |
| @@ -6078,6 +6078,10 @@ __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); |
