From: Li Zhong Date: Mon, 19 Sep 2016 21:43:52 +0000 (-0700) Subject: mem-hotplug: don't clear the only node in new_node_page() X-Git-Tag: v4.8-rc8~29^2~19 X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=9bb627be47a574b764e162e8513d5db78d49e7f5 mem-hotplug: don't clear the only node in new_node_page() Commit 394e31d2ceb4 ("mem-hotplug: alloc new page from a nearest neighbor node when mem-offline") introduced new_node_page() for memory hotplug. In new_node_page(), the nid is cleared before calling __alloc_pages_nodemask(). But if it is the only node of the system, and the first round allocation fails, it will not be able to get memory from an empty nodemask, and will trigger oom. The patch checks whether it is the last node on the system, and if it is, then don't clear the nid in the nodemask. Fixes: 394e31d2ceb4 ("mem-hotplug: alloc new page from a nearest neighbor node when mem-offline") Link: http://lkml.kernel.org/r/1473044391.4250.19.camel@TP420 Signed-off-by: Li Zhong Reported-by: John Allen Acked-by: Vlastimil Babka Cc: Xishi Qiu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 41266dc29f33..b58906b6215c 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1567,7 +1567,9 @@ static struct page *new_node_page(struct page *page, unsigned long private, return alloc_huge_page_node(page_hstate(compound_head(page)), next_node_in(nid, nmask)); - node_clear(nid, nmask); + if (nid != next_node_in(nid, nmask)) + node_clear(nid, nmask); + if (PageHighMem(page) || (zone_idx(page_zone(page)) == ZONE_MOVABLE)) gfp_mask |= __GFP_HIGHMEM;