[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>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e12154d..b9fd2c2 100644 (file)
--- 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);