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authorJoonsoo Kim <iamjoonsoo.kim@lge.com>2014-12-12 16:55:49 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-13 12:42:48 -0800
commite30825f1869a75b29a69dc8e0aaaaccc492092cf (patch)
tree33adc902e098cf23d8a8b9d97ad01b1d06e28e93 /mm/page_alloc.c
parenteefa864b701d78dc9753c70a3540a2e9ae192595 (diff)
mm/debug-pagealloc: prepare boottime configurable on/off
Until now, debug-pagealloc needs extra flags in struct page, so we need to recompile whole source code when we decide to use it. This is really painful, because it takes some time to recompile and sometimes rebuild is not possible due to third party module depending on struct page. So, we can't use this good feature in many cases. Now, we have the page extension feature that allows us to insert extra flags to outside of struct page. This gets rid of third party module issue mentioned above. And, this allows us to determine if we need extra memory for this page extension in boottime. With these property, we can avoid using debug-pagealloc in boottime with low computational overhead in the kernel built with CONFIG_DEBUG_PAGEALLOC. This will help our development process greatly. This patch is the preparation step to achive above goal. debug-pagealloc originally uses extra field of struct page, but, after this patch, it will use field of struct page_ext. Because memory for page_ext is allocated later than initialization of page allocator in CONFIG_SPARSEMEM, we should disable debug-pagealloc feature temporarily until initialization of page_ext. This patch implements this. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Dave Hansen <dave@sr71.net> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Jungsoo Son <jungsoo.son@lge.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c38
1 files changed, 35 insertions, 3 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b64666cf5865..e0a39d328ca1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -56,7 +56,7 @@
#include <linux/prefetch.h>
#include <linux/mm_inline.h>
#include <linux/migrate.h>
-#include <linux/page-debug-flags.h>
+#include <linux/page_ext.h>
#include <linux/hugetlb.h>
#include <linux/sched/rt.h>
@@ -425,6 +425,22 @@ static inline void prep_zero_page(struct page *page, unsigned int order,
#ifdef CONFIG_DEBUG_PAGEALLOC
unsigned int _debug_guardpage_minorder;
+bool _debug_guardpage_enabled __read_mostly;
+
+static bool need_debug_guardpage(void)
+{
+ return true;
+}
+
+static void init_debug_guardpage(void)
+{
+ _debug_guardpage_enabled = true;
+}
+
+struct page_ext_operations debug_guardpage_ops = {
+ .need = need_debug_guardpage,
+ .init = init_debug_guardpage,
+};
static int __init debug_guardpage_minorder_setup(char *buf)
{
@@ -443,7 +459,14 @@ __setup("debug_guardpage_minorder=", debug_guardpage_minorder_setup);
static inline void set_page_guard(struct zone *zone, struct page *page,
unsigned int order, int migratetype)
{
- __set_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
+ struct page_ext *page_ext;
+
+ if (!debug_guardpage_enabled())
+ return;
+
+ page_ext = lookup_page_ext(page);
+ __set_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
+
INIT_LIST_HEAD(&page->lru);
set_page_private(page, order);
/* Guard pages are not available for any usage */
@@ -453,12 +476,20 @@ static inline void 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)
{
- __clear_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
+ struct page_ext *page_ext;
+
+ if (!debug_guardpage_enabled())
+ return;
+
+ page_ext = lookup_page_ext(page);
+ __clear_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
+
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 = { NULL, };
static inline void set_page_guard(struct zone *zone, struct page *page,
unsigned int order, int migratetype) {}
static inline void clear_page_guard(struct zone *zone, struct page *page,
@@ -869,6 +900,7 @@ static inline void expand(struct zone *zone, struct page *page,
VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC) &&
+ debug_guardpage_enabled() &&
high < debug_guardpage_minorder()) {
/*
* Mark as guard pages (or page), that will allow to