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From: Christoph Lameter on 3 Aug 2010 23:00
Extract the code that memory checkers and other verification tools use from
the hotpaths. Makes it easier to add new ones and reduces the disturbances
of the hotpaths.

Signed-off-by: Christoph Lameter <cl(a)linux-foundation.org>

---
mm/slub.c | 49 ++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 38 insertions(+), 11 deletions(-)

Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2010-07-26 14:26:24.000000000 -0500
+++ linux-2.6/mm/slub.c 2010-07-26 14:26:33.000000000 -0500
@@ -793,6 +793,37 @@ static void trace(struct kmem_cache *s,
}

/*
+ * Hooks for other subsystems that check memory allocations. In a typical
+ * production configuration these hooks all should produce no code at all.
+ */
+static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
+{
+ lockdep_trace_alloc(flags);
+ might_sleep_if(flags & __GFP_WAIT);
+
+ return should_failslab(s->objsize, flags, s->flags);
+}
+
+static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
+{
+ kmemcheck_slab_alloc(s, flags, object, s->objsize);
+ kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags);
+}
+
+static inline void slab_free_hook(struct kmem_cache *s, void *x)
+{
+ kmemleak_free_recursive(x, s->flags);
+}
+
+static inline void slab_free_hook_irq(struct kmem_cache *s, void *object)
+{
+ kmemcheck_slab_free(s, object, s->objsize);
+ debug_check_no_locks_freed(object, s->objsize);
+ if (!(s->flags & SLAB_DEBUG_OBJECTS))
+ debug_check_no_obj_freed(object, s->objsize);
+}
+
+/*
* Tracking of fully allocated slabs for debugging purposes.
*/
static void add_full(struct kmem_cache_node *n, struct page *page)
@@ -1698,10 +1729,7 @@ static __always_inline void *slab_alloc(

gfpflags &= gfp_allowed_mask;

- lockdep_trace_alloc(gfpflags);
- might_sleep_if(gfpflags & __GFP_WAIT);
-
- if (should_failslab(s->objsize, gfpflags, s->flags))
+ if (!slab_pre_alloc_hook(s, gfpflags))
return NULL;

local_irq_save(flags);
@@ -1720,8 +1748,7 @@ static __always_inline void *slab_alloc(
if (unlikely(gfpflags & __GFP_ZERO) && object)
memset(object, 0, s->objsize);

- kmemcheck_slab_alloc(s, gfpflags, object, s->objsize);
- kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, gfpflags);
+ slab_post_alloc_hook(s, gfpflags, object);

return object;
}
@@ -1851,13 +1878,13 @@ static __always_inline void slab_free(st
struct kmem_cache_cpu *c;
unsigned long flags;

- kmemleak_free_recursive(x, s->flags);
+ slab_free_hook(s, x);
+
local_irq_save(flags);
c = __this_cpu_ptr(s->cpu_slab);
- kmemcheck_slab_free(s, object, s->objsize);
- debug_check_no_locks_freed(object, s->objsize);
- if (!(s->flags & SLAB_DEBUG_OBJECTS))
- debug_check_no_obj_freed(object, s->objsize);
+
+ slab_free_hook_irq(s, x);
+
if (likely(page == c->page && c->node >= 0)) {
set_freepointer(s, object, c->freelist);
c->freelist = object;

--
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Prev: [S+Q3 07/23] slub: Use kmem_cache flags to detect if slab is in debugging mode.
Next: [S+Q3 04/23] SLUB: Constants need UL