mm: meminit: remove mminit_verify_page_links

mminit_verify_page_links() is an extremely paranoid check that was
introduced when memory initialisation was being heavily reworked.
Profiles indicated that up to 10% of parallel memory initialisation was
spent on checking this for every page.  The cost could be reduced but in
practice this check only found problems very early during the
initialisation rewrite and has found nothing since.  This patch removes an
expensive unnecessary check.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 0 insertions, 17 deletions

diff --git a/mm/internal.h b/mm/internal.h
index 71d1604..a48cbef 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -362,10 +362,7 @@ do { \
 } while (0)
 
 extern void mminit_verify_pageflags_layout(void);
-extern void mminit_verify_page_links(struct page *page,
-		enum zone_type zone, unsigned long nid, unsigned long pfn);
 extern void mminit_verify_zonelist(void);
-
 #else
 
 static inline void mminit_dprintk(enum mminit_level level,
@@ -377,11 +374,6 @@ static inline void mminit_verify_pageflags_layout(void)
 {
 }
 
-static inline void mminit_verify_page_links(struct page *page,
-		enum zone_type zone, unsigned long nid, unsigned long pfn)
-{
-}
-
 static inline void mminit_verify_zonelist(void)
 {
 }
diff --git a/mm/mm_init.c b/mm/mm_init.c
index 28fbf87..fdadf91 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -131,14 +131,6 @@ void __init mminit_verify_pageflags_layout(void)
 	BUG_ON(or_mask != add_mask);
 }
 
-void __meminit mminit_verify_page_links(struct page *page, enum zone_type zone,
-			unsigned long nid, unsigned long pfn)
-{
-	BUG_ON(page_to_nid(page) != nid);
-	BUG_ON(page_zonenum(page) != zone);
-	BUG_ON(page_to_pfn(page) != pfn);
-}
-
 static __init int set_mminit_loglevel(char *str)
 {
 	get_option(&str, &mminit_loglevel);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f1f455a..5a38e39 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -839,7 +839,6 @@ static void __meminit __init_single_page(struct page *page, unsigned long pfn,
 				unsigned long zone, int nid)
 {
 	set_page_links(page, zone, nid, pfn);
-	mminit_verify_page_links(page, zone, nid, pfn);
 	init_page_count(page);
 	page_mapcount_reset(page);
 	page_cpupid_reset_last(page);