[PATCH] mm: bad_page optimisation

Cut down size slightly by not passing bad_page the function name (it should be
able to be determined by dump_stack()).  And cut down the number of printks in
bad_page.

Also, cut down some branching in the destroy_compound_page path.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 20 insertions, 24 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e12154d9c4ed..b9fd2c238f13 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -132,16 +132,16 @@ static inline int bad_range(struct zone *zone, struct page *page)
 }
 #endif
 
-static void bad_page(const char *function, struct page *page)
-{
-        printk(KERN_EMERG "Bad page state at %s (in process '%s', page %p)\n",
-                function, current->comm, page);
-        printk(KERN_EMERG "flags:0x%0*lx mapping:%p mapcount:%d count:%d\n",
-                (int)(2*sizeof(unsigned long)), (unsigned long)page->flags,
-                page->mapping, page_mapcount(page), page_count(page));
-        printk(KERN_EMERG "Backtrace:\n");
+static void bad_page(struct page *page)
+{
+        printk(KERN_EMERG "Bad page state in process '%s'\n"
+                "page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n"
+                "Trying to fix it up, but a reboot is needed\n"
+                "Backtrace:\n",
+                current->comm, page, (int)(2*sizeof(unsigned long)),
+                (unsigned long)page->flags, page->mapping,
+                page_mapcount(page), page_count(page));
         dump_stack();
-        printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n");
         page->flags &= ~(1 << PG_lru    |
                         1 << PG_private |
                         1 << PG_locked  |
@@ -194,19 +194,15 @@ static void destroy_compound_page(struct page *page, unsigned long order)
         int i;
         int nr_pages = 1 << order;
 
-        if (!PageCompound(page))
-                return;
-
-        if (page[1].index != order)
-                bad_page(__FUNCTION__, page);
+        if (unlikely(page[1].index != order))
+                bad_page(page);
 
         for (i = 0; i < nr_pages; i++) {
                 struct page *p = page + i;
 
-                if (!PageCompound(p))
-                        bad_page(__FUNCTION__, page);
-                if (page_private(p) != (unsigned long)page)
-                        bad_page(__FUNCTION__, page);
+                if (unlikely(!PageCompound(p) |
+                                (page_private(p) != (unsigned long)page)))
+                        bad_page(page);
                 ClearPageCompound(p);
         }
 }
@@ -316,7 +312,7 @@ static inline void __free_pages_bulk (struct page *page,
         unsigned long page_idx;
         int order_size = 1 << order;
 
-        if (unlikely(order))
+        if (unlikely(PageCompound(page)))
                 destroy_compound_page(page, order);
 
         page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
@@ -348,7 +344,7 @@ static inline void __free_pages_bulk (struct page *page,
         zone->free_area[order].nr_free++;
 }
 
-static inline int free_pages_check(const char *function, struct page *page)
+static inline int free_pages_check(struct page *page)
 {
         if (unlikely(page_mapcount(page) |
                 (page->mapping != NULL)  |
@@ -363,7 +359,7 @@ static inline int free_pages_check(const char *function, struct page *page)
                         1 << PG_swapcache |
                         1 << PG_writeback |
                         1 << PG_reserved ))))
-                bad_page(function, page);
+                bad_page(page);
         if (PageDirty(page))
                 __ClearPageDirty(page);
         /*
@@ -422,7 +418,7 @@ void __free_pages_ok(struct page *page, unsigned int order)
 #endif
 
         for (i = 0 ; i < (1 << order) ; ++i)
-                reserved += free_pages_check(__FUNCTION__, page + i);
+                reserved += free_pages_check(page + i);
         if (reserved)
                 return;
 
@@ -517,7 +513,7 @@ static int prep_new_page(struct page *page, int order)
                         1 << PG_swapcache |
                         1 << PG_writeback |
                         1 << PG_reserved ))))
-                bad_page(__FUNCTION__, page);
+                bad_page(page);
 
         /*
          * For now, we report if PG_reserved was found set, but do not
@@ -716,7 +712,7 @@ static void fastcall free_hot_cold_page(struct page *page, int cold)
 
         if (PageAnon(page))
                 page->mapping = NULL;
-        if (free_pages_check(__FUNCTION__, page))
+        if (free_pages_check(page))
                 return;
 
         inc_page_state(pgfree);