Commit c1470b33 authored Aug 11, 2016 by zhong jiang Committed by Linus Torvalds Aug 11, 2016

mm/hugetlb: fix incorrect hugepages count during mem hotplug

When memory hotplug operates, free hugepages will be freed if the
movable node is offline.  Therefore, /proc/sys/vm/nr_hugepages will be
incorrect.

Fix it by reducing max_huge_pages when the node is offlined.

n-horiguchi@ah.jp.nec.com said:

: dissolve_free_huge_page intends to break a hugepage into buddy, and the
: destination hugepage is supposed to be allocated from the pool of the
: destination node, so the system-wide pool size is reduced.  So adding
: h->max_huge_pages-- makes sense to me.

Link: http://lkml.kernel.org/r/1470624546-902-1-git-send-email-zhongjiang@huawei.com


Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 85e97be3

mm/hugetlb.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1448,6 +1448,7 @@ static void dissolve_free_huge_page(struct page *page)
		list_del(&page->lru);
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
		h->max_huge_pages--;
		update_and_free_page(h, page);
		}
		spin_unlock(&hugetlb_lock);

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