On Sun 26 May 2013 01:58:36 PM CST, Wanpeng Li wrote:
> Changelog:
> v1 -> v2:
> * show number of HighTotal before hotremove
> * remove CONFIG_HIGHMEM
> * cc stable kernels
> * add Michal reviewed-by
>
> 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.
>
> Stable for 2.6.24+.
>
> 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
>
> Reviewed-by: Michal Hocko <mhocko@xxxxxxx>
> Signed-off-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
> ---
> mm/page_alloc.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 98cbdf6..23b921f 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -6140,6 +6140,8 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
> list_del(&page->lru);
> rmv_page_order(page);
> zone->free_area[order].nr_free--;
> + if (PageHighMem(page))
> + totalhigh_pages -= 1 << order;
> for (i = 0; i < (1 << order); i++)
> SetPageReserved((page+i));
> pfn += (1 << order);
Hi Wanpeng,
The memory hotplug code adjusts totalram_pages,
totalhigh_pages, zone->present_pages
and zone->managed_pages all in memory_hotplug.c, so suggest to move
this into memory_hotplug.c
too.
One of my patch fixes this issue in another way, please refer
to:
http://marc.info/?l=linux-mm&m=136957578620221&w=2
Regards!
Gerry
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