slub: record page flag overlays explicitly
SLUB reuses two page bits for internal purposes, it overlays PG_active and
PG_error. This is hidden away in slub.c. Document these overlays
explicitly in the main page-flags enum along with all the others.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/slub.c b/mm/slub.c
index 6d4a49c..77c21cf 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -102,44 +102,12 @@
* the fast path and disables lockless freelists.
*/
-#define FROZEN (1 << PG_active)
-
#ifdef CONFIG_SLUB_DEBUG
-#define SLABDEBUG (1 << PG_error)
+#define SLABDEBUG 1
#else
#define SLABDEBUG 0
#endif
-static inline int SlabFrozen(struct page *page)
-{
- return page->flags & FROZEN;
-}
-
-static inline void SetSlabFrozen(struct page *page)
-{
- page->flags |= FROZEN;
-}
-
-static inline void ClearSlabFrozen(struct page *page)
-{
- page->flags &= ~FROZEN;
-}
-
-static inline int SlabDebug(struct page *page)
-{
- return page->flags & SLABDEBUG;
-}
-
-static inline void SetSlabDebug(struct page *page)
-{
- page->flags |= SLABDEBUG;
-}
-
-static inline void ClearSlabDebug(struct page *page)
-{
- page->flags &= ~SLABDEBUG;
-}
-
/*
* Issues still to be resolved:
*
@@ -971,7 +939,7 @@
}
/* Special debug activities for freeing objects */
- if (!SlabFrozen(page) && !page->freelist)
+ if (!PageSlubFrozen(page) && !page->freelist)
remove_full(s, page);
if (s->flags & SLAB_STORE_USER)
set_track(s, object, TRACK_FREE, addr);
@@ -1157,7 +1125,7 @@
page->flags |= 1 << PG_slab;
if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON |
SLAB_STORE_USER | SLAB_TRACE))
- SetSlabDebug(page);
+ __SetPageSlubDebug(page);
start = page_address(page);
@@ -1184,14 +1152,14 @@
int order = compound_order(page);
int pages = 1 << order;
- if (unlikely(SlabDebug(page))) {
+ if (unlikely(SLABDEBUG && PageSlubDebug(page))) {
void *p;
slab_pad_check(s, page);
for_each_object(p, s, page_address(page),
page->objects)
check_object(s, page, p, 0);
- ClearSlabDebug(page);
+ __ClearPageSlubDebug(page);
}
mod_zone_page_state(page_zone(page),
@@ -1288,7 +1256,7 @@
if (slab_trylock(page)) {
list_del(&page->lru);
n->nr_partial--;
- SetSlabFrozen(page);
+ __SetPageSlubFrozen(page);
return 1;
}
return 0;
@@ -1398,7 +1366,7 @@
struct kmem_cache_node *n = get_node(s, page_to_nid(page));
struct kmem_cache_cpu *c = get_cpu_slab(s, smp_processor_id());
- ClearSlabFrozen(page);
+ __ClearPageSlubFrozen(page);
if (page->inuse) {
if (page->freelist) {
@@ -1406,7 +1374,8 @@
stat(c, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
} else {
stat(c, DEACTIVATE_FULL);
- if (SlabDebug(page) && (s->flags & SLAB_STORE_USER))
+ if (SLABDEBUG && PageSlubDebug(page) &&
+ (s->flags & SLAB_STORE_USER))
add_full(n, page);
}
slab_unlock(page);
@@ -1551,7 +1520,7 @@
object = c->page->freelist;
if (unlikely(!object))
goto another_slab;
- if (unlikely(SlabDebug(c->page)))
+ if (unlikely(SLABDEBUG && PageSlubDebug(c->page)))
goto debug;
c->freelist = object[c->offset];
@@ -1588,7 +1557,7 @@
if (c->page)
flush_slab(s, c);
slab_lock(new);
- SetSlabFrozen(new);
+ __SetPageSlubFrozen(new);
c->page = new;
goto load_freelist;
}
@@ -1674,7 +1643,7 @@
stat(c, FREE_SLOWPATH);
slab_lock(page);
- if (unlikely(SlabDebug(page)))
+ if (unlikely(SLABDEBUG && PageSlubDebug(page)))
goto debug;
checks_ok:
@@ -1682,7 +1651,7 @@
page->freelist = object;
page->inuse--;
- if (unlikely(SlabFrozen(page))) {
+ if (unlikely(PageSlubFrozen(page))) {
stat(c, FREE_FROZEN);
goto out_unlock;
}
@@ -3317,12 +3286,12 @@
s->name, page);
if (s->flags & DEBUG_DEFAULT_FLAGS) {
- if (!SlabDebug(page))
- printk(KERN_ERR "SLUB %s: SlabDebug not set "
+ if (!PageSlubDebug(page))
+ printk(KERN_ERR "SLUB %s: SlubDebug not set "
"on slab 0x%p\n", s->name, page);
} else {
- if (SlabDebug(page))
- printk(KERN_ERR "SLUB %s: SlabDebug set on "
+ if (PageSlubDebug(page))
+ printk(KERN_ERR "SLUB %s: SlubDebug set on "
"slab 0x%p\n", s->name, page);
}
}