From 4468b8f1e2d32ce79ef4bcb8e00d7e88627f1c3a Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Fri, 22 Feb 2013 16:34:46 -0800 Subject: mm: uninline page_xchg_last_nid() Andrew Morton pointed out that page_xchg_last_nid() and reset_page_last_nid() were "getting nuttily large" and asked that it be investigated. reset_page_last_nid() is on the page free path and it would be unfortunate to make that path more expensive than it needs to be. Due to the internal use of page_xchg_last_nid() it is already too expensive but fortunately, it should also be impossible for the page->flags to be updated in parallel when we call reset_page_last_nid(). Instead of unlining the function, it uses a simplier implementation that assumes no parallel updates and should now be sufficiently short for inlining. page_xchg_last_nid() is called in paths that are already quite expensive (splitting huge page, fault handling, migration) and it is reasonable to uninline. There was not really a good place to place the function but mm/mmzone.c was the closest fit IMO. This patch saved 128 bytes of text in the vmlinux file for the kernel configuration I used for testing automatic NUMA balancing. Signed-off-by: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 21 +++++---------------- 1 file changed, 5 insertions(+), 16 deletions(-) (limited to 'include') diff --git a/include/linux/mm.h b/include/linux/mm.h index 437da0ce78c7..8a5bbe3b9e56 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -677,25 +677,14 @@ static inline int page_last_nid(struct page *page) return (page->flags >> LAST_NID_PGSHIFT) & LAST_NID_MASK; } -static inline int page_xchg_last_nid(struct page *page, int nid) -{ - unsigned long old_flags, flags; - int last_nid; - - do { - old_flags = flags = page->flags; - last_nid = page_last_nid(page); - - flags &= ~(LAST_NID_MASK << LAST_NID_PGSHIFT); - flags |= (nid & LAST_NID_MASK) << LAST_NID_PGSHIFT; - } while (unlikely(cmpxchg(&page->flags, old_flags, flags) != old_flags)); - - return last_nid; -} +extern int page_xchg_last_nid(struct page *page, int nid); static inline void reset_page_last_nid(struct page *page) { - page_xchg_last_nid(page, (1 << LAST_NID_SHIFT) - 1); + int nid = (1 << LAST_NID_SHIFT) - 1; + + page->flags &= ~(LAST_NID_MASK << LAST_NID_PGSHIFT); + page->flags |= (nid & LAST_NID_MASK) << LAST_NID_PGSHIFT; } #endif /* LAST_NID_NOT_IN_PAGE_FLAGS */ #else -- cgit v1.2.3