On Tue 27-09-16 15:07:09, Andrew Morton wrote:
> From: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
> Subject: mem-hotplug: use nodes that contain memory as mask in new_node_page()
>
> 9bb627be47a5 ("mem-hotplug: don't clear the only node in new_node_page()")
> prevents allocating from an empty nodemask, but as David points out, it is
> still wrong. As node_online_map may include memoryless nodes, only
> allocating from these nodes is meaningless.
>
> This patch uses node_states[N_MEMORY] mask to prevent the above case.
>
> Fixes: 9bb627be47a5 ("mem-hotplug: don't clear the only node in new_node_page()")
> Fixes: 394e31d2ceb4 ("mem-hotplug: alloc new page from a nearest neighbor node when mem-offline")
> Link: http://lkml.kernel.org/r/1474447117.28370.6.camel@TP420
> Signed-off-by: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
> Suggested-by: David Rientjes <rientjes@xxxxxxxxxx>
> Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
> Cc: John Allen <jallen@xxxxxxxxxxxxxxxxxx>
> Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx>
> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> ---
>
> mm/memory_hotplug.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff -puN mm/memory_hotplug.c~mem-hotplug-use-nodes-that-contain-memory-as-mask-in-new_node_page mm/memory_hotplug.c
> --- a/mm/memory_hotplug.c~mem-hotplug-use-nodes-that-contain-memory-as-mask-in-new_node_page
> +++ a/mm/memory_hotplug.c
> @@ -1555,8 +1555,8 @@ static struct page *new_node_page(struct
> {
> gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;
> int nid = page_to_nid(page);
> - nodemask_t nmask = node_online_map;
> - struct page *new_page;
> + nodemask_t nmask = node_states[N_MEMORY];
> + struct page *new_page = NULL;
>
> /*
> * TODO: allocate a destination hugepage from a nearest neighbor node,
> @@ -1567,14 +1567,14 @@ static struct page *new_node_page(struct
> return alloc_huge_page_node(page_hstate(compound_head(page)),
> next_node_in(nid, nmask));
>
> - if (nid != next_node_in(nid, nmask))
> - node_clear(nid, nmask);
> + node_clear(nid, nmask);
>
> if (PageHighMem(page)
> || (zone_idx(page_zone(page)) == ZONE_MOVABLE))
> gfp_mask |= __GFP_HIGHMEM;
>
> - new_page = __alloc_pages_nodemask(gfp_mask, 0,
> + if (!nodes_empty(nmask))
> + new_page = __alloc_pages_nodemask(gfp_mask, 0,
> node_zonelist(nid, gfp_mask), &nmask);
> if (!new_page)
> new_page = __alloc_pages(gfp_mask, 0,
> _
>
> Patches currently in -mm which might be from zhong@xxxxxxxxxxxxxxxxxx are
>
> mem-hotplug-use-nodes-that-contain-memory-as-mask-in-new_node_page.patch
--
Michal Hocko
SUSE Labs
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