From 4e41a30c6d506c884d3da9aeb316352e70679d4b Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Fri, 15 Jan 2016 16:54:07 -0800 Subject: mm: hwpoison: adjust for new thp refcounting Some mm-related BUG_ON()s could trigger from hwpoison code due to recent changes in thp refcounting rule. This patch fixes them up. In the new refcounting, we no longer use tail->_mapcount to keep tail's refcount, and thereby we can simplify get/put_hwpoison_page(). And another change is that tail's refcount is not transferred to the raw page during thp split (more precisely, in new rule we don't take refcount on tail page any more.) So when we need thp split, we have to transfer the refcount properly to the 4kB soft-offlined page before migration. thp split code goes into core code only when precheck (total_mapcount(head) == page_count(head) - 1) passes to avoid useless split, where we assume that one refcount is held by the caller of thp split and the others are taken via mapping. To meet this assumption, this patch moves thp split part in soft_offline_page() after get_any_page(). [akpm@linux-foundation.org: remove unneeded #define, per Kirill] Signed-off-by: Naoya Horiguchi Acked-by: Kirill A. Shutemov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/mm.h b/include/linux/mm.h index 6b56cfd9fd09..e4397f640e86 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2217,7 +2217,7 @@ extern int memory_failure(unsigned long pfn, int trapno, int flags); extern void memory_failure_queue(unsigned long pfn, int trapno, int flags); extern int unpoison_memory(unsigned long pfn); extern int get_hwpoison_page(struct page *page); -extern void put_hwpoison_page(struct page *page); +#define put_hwpoison_page(page) put_page(page) extern int sysctl_memory_failure_early_kill; extern int sysctl_memory_failure_recovery; extern void shake_page(struct page *p, int access); -- cgit v1.2.3