mm, debug_pagealloc: use a page type instead of page_ext flag
When debug_pagealloc is enabled, we currently allocate the page_ext
array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag. Now that
we have the page_type field in struct page, we can use that instead, as
guard pages are neither PageSlab nor mapped to userspace. This reduces
memory overhead when debug_pagealloc is enabled and there are no other
features requiring the page_ext array.
Link: http://lkml.kernel.org/r/20190603143451.27353-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 26b6ad8..ae56e8f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -50,7 +50,6 @@
#include <linux/backing-dev.h>
#include <linux/fault-inject.h>
#include <linux/page-isolation.h>
-#include <linux/page_ext.h>
#include <linux/debugobjects.h>
#include <linux/kmemleak.h>
#include <linux/compaction.h>
@@ -668,18 +667,6 @@ static int __init early_debug_pagealloc(char *buf)
}
early_param("debug_pagealloc", early_debug_pagealloc);
-static bool need_debug_guardpage(void)
-{
- /* If we don't use debug_pagealloc, we don't need guard page */
- if (!debug_pagealloc_enabled())
- return false;
-
- if (!debug_guardpage_minorder())
- return false;
-
- return true;
-}
-
static void init_debug_guardpage(void)
{
if (!debug_pagealloc_enabled())
@@ -691,11 +678,6 @@ static void init_debug_guardpage(void)
static_branch_enable(&_debug_guardpage_enabled);
}
-struct page_ext_operations debug_guardpage_ops = {
- .need = need_debug_guardpage,
- .init = init_debug_guardpage,
-};
-
static int __init debug_guardpage_minorder_setup(char *buf)
{
unsigned long res;
@@ -713,20 +695,13 @@ early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
static inline bool set_page_guard(struct zone *zone, struct page *page,
unsigned int order, int migratetype)
{
- struct page_ext *page_ext;
-
if (!debug_guardpage_enabled())
return false;
if (order >= debug_guardpage_minorder())
return false;
- page_ext = lookup_page_ext(page);
- if (unlikely(!page_ext))
- return false;
-
- __set_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
-
+ __SetPageGuard(page);
INIT_LIST_HEAD(&page->lru);
set_page_private(page, order);
/* Guard pages are not available for any usage */
@@ -738,23 +713,16 @@ static inline bool set_page_guard(struct zone *zone, struct page *page,
static inline void clear_page_guard(struct zone *zone, struct page *page,
unsigned int order, int migratetype)
{
- struct page_ext *page_ext;
-
if (!debug_guardpage_enabled())
return;
- page_ext = lookup_page_ext(page);
- if (unlikely(!page_ext))
- return;
-
- __clear_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
+ __ClearPageGuard(page);
set_page_private(page, 0);
if (!is_migrate_isolate(migratetype))
__mod_zone_freepage_state(zone, (1 << order), migratetype);
}
#else
-struct page_ext_operations debug_guardpage_ops;
static inline bool set_page_guard(struct zone *zone, struct page *page,
unsigned int order, int migratetype) { return false; }
static inline void clear_page_guard(struct zone *zone, struct page *page,
@@ -1930,6 +1898,10 @@ void __init page_alloc_init_late(void)
for_each_populated_zone(zone)
set_zone_contiguous(zone);
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+ init_debug_guardpage();
+#endif
}
#ifdef CONFIG_CMA