From c3114a84f7f96c9d5c73c8bfa7e21ff42fda97e2 Mon Sep 17 00:00:00 2001 From: Anshuman Khandual Date: Mon, 10 Jul 2017 15:47:41 -0700 Subject: mm: hugetlb: soft-offline: dissolve source hugepage after successful migration Currently hugepage migrated by soft-offline (i.e. due to correctable memory errors) is contained as a hugepage, which means many non-error pages in it are unreusable, i.e. wasted. This patch solves this issue by dissolving source hugepages into buddy. As done in previous patch, PageHWPoison is set only on a head page of the error hugepage. Then in dissoliving we move the PageHWPoison flag to the raw error page so that all healthy subpages return back to buddy. [arnd@arndb.de: fix warnings: replace some macros with inline functions] Link: http://lkml.kernel.org/r/20170609102544.2947326-1-arnd@arndb.de Link: http://lkml.kernel.org/r/1496305019-5493-5-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Anshuman Khandual Signed-off-by: Naoya Horiguchi Signed-off-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'mm/hugetlb.c') diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 41a1b48cefbf..b2d44363837a 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1459,7 +1459,7 @@ static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, * number of free hugepages would be reduced below the number of reserved * hugepages. */ -static int dissolve_free_huge_page(struct page *page) +int dissolve_free_huge_page(struct page *page) { int rc = 0; @@ -1472,6 +1472,14 @@ static int dissolve_free_huge_page(struct page *page) rc = -EBUSY; goto out; } + /* + * Move PageHWPoison flag from head page to the raw error page, + * which makes any subpages rather than the error page reusable. + */ + if (PageHWPoison(head) && page != head) { + SetPageHWPoison(page); + ClearPageHWPoison(head); + } list_del(&head->lru); h->free_huge_pages--; h->free_huge_pages_node[nid]--; -- cgit v1.2.3