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authorMel Gorman <mgorman@suse.de>2013-02-22 16:34:46 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-23 17:50:18 -0800
commit4468b8f1e2d32ce79ef4bcb8e00d7e88627f1c3a (patch)
treea73555b462198c396da08acab928a788f3733b71 /include/linux/mm.h
parent6acc8b02517d7063b25490b26215834bd2f363c8 (diff)
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 <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/mm.h')
-rw-r--r--include/linux/mm.h21
1 files changed, 5 insertions, 16 deletions
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