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-rw-r--r--mm/slab.c89
1 files changed, 68 insertions, 21 deletions
diff --git a/mm/slab.c b/mm/slab.c
index b264214c77ea..6dd8d5f3a3ac 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -375,6 +375,39 @@ static void **dbg_userword(struct kmem_cache *cachep, void *objp)
#endif
+#define OBJECT_FREE (0)
+#define OBJECT_ACTIVE (1)
+
+#ifdef CONFIG_DEBUG_SLAB_LEAK
+
+static void set_obj_status(struct page *page, int idx, int val)
+{
+ int freelist_size;
+ char *status;
+ struct kmem_cache *cachep = page->slab_cache;
+
+ freelist_size = cachep->num * sizeof(unsigned int);
+ status = (char *)page->freelist + freelist_size;
+ status[idx] = val;
+}
+
+static inline unsigned int get_obj_status(struct page *page, int idx)
+{
+ int freelist_size;
+ char *status;
+ struct kmem_cache *cachep = page->slab_cache;
+
+ freelist_size = cachep->num * sizeof(unsigned int);
+ status = (char *)page->freelist + freelist_size;
+
+ return status[idx];
+}
+
+#else
+static inline void set_obj_status(struct page *page, int idx, int val) {}
+
+#endif
+
/*
* Do not go above this order unless 0 objects fit into the slab or
* overridden on the command line.
@@ -565,9 +598,18 @@ static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
return cachep->array[smp_processor_id()];
}
-static size_t slab_mgmt_size(size_t nr_objs, size_t align)
+static size_t calculate_freelist_size(int nr_objs, size_t align)
{
- return ALIGN(nr_objs * sizeof(unsigned int), align);
+ size_t freelist_size;
+
+ freelist_size = nr_objs * sizeof(unsigned int);
+ if (IS_ENABLED(CONFIG_DEBUG_SLAB_LEAK))
+ freelist_size += nr_objs * sizeof(char);
+
+ if (align)
+ freelist_size = ALIGN(freelist_size, align);
+
+ return freelist_size;
}
/*
@@ -600,6 +642,10 @@ static void cache_estimate(unsigned long gfporder, size_t buffer_size,
nr_objs = slab_size / buffer_size;
} else {
+ int extra_space = 0;
+
+ if (IS_ENABLED(CONFIG_DEBUG_SLAB_LEAK))
+ extra_space = sizeof(char);
/*
* Ignore padding for the initial guess. The padding
* is at most @align-1 bytes, and @buffer_size is at
@@ -608,17 +654,18 @@ static void cache_estimate(unsigned long gfporder, size_t buffer_size,
* into the memory allocation when taking the padding
* into account.
*/
- nr_objs = (slab_size) / (buffer_size + sizeof(unsigned int));
+ nr_objs = (slab_size) /
+ (buffer_size + sizeof(unsigned int) + extra_space);
/*
* This calculated number will be either the right
* amount, or one greater than what we want.
*/
- if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
- > slab_size)
+ if (calculate_freelist_size(nr_objs, align) >
+ slab_size - nr_objs * buffer_size)
nr_objs--;
- mgmt_size = slab_mgmt_size(nr_objs, align);
+ mgmt_size = calculate_freelist_size(nr_objs, align);
}
*num = nr_objs;
*left_over = slab_size - nr_objs*buffer_size - mgmt_size;
@@ -2011,13 +2058,16 @@ static size_t calculate_slab_order(struct kmem_cache *cachep,
continue;
if (flags & CFLGS_OFF_SLAB) {
+ size_t freelist_size_per_obj = sizeof(unsigned int);
/*
* Max number of objs-per-slab for caches which
* use off-slab slabs. Needed to avoid a possible
* looping condition in cache_grow().
*/
+ if (IS_ENABLED(CONFIG_DEBUG_SLAB_LEAK))
+ freelist_size_per_obj += sizeof(char);
offslab_limit = size;
- offslab_limit /= sizeof(unsigned int);
+ offslab_limit /= freelist_size_per_obj;
if (num > offslab_limit)
break;
@@ -2258,8 +2308,7 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
if (!cachep->num)
return -E2BIG;
- freelist_size =
- ALIGN(cachep->num * sizeof(unsigned int), cachep->align);
+ freelist_size = calculate_freelist_size(cachep->num, cachep->align);
/*
* If the slab has been placed off-slab, and we have enough space then
@@ -2272,7 +2321,7 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
if (flags & CFLGS_OFF_SLAB) {
/* really off slab. No need for manual alignment */
- freelist_size = cachep->num * sizeof(unsigned int);
+ freelist_size = calculate_freelist_size(cachep->num, 0);
#ifdef CONFIG_PAGE_POISONING
/* If we're going to use the generic kernel_map_pages()
@@ -2589,6 +2638,7 @@ static void cache_init_objs(struct kmem_cache *cachep,
if (cachep->ctor)
cachep->ctor(objp);
#endif
+ set_obj_status(page, i, OBJECT_FREE);
slab_freelist(page)[i] = i;
}
}
@@ -2797,6 +2847,7 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
BUG_ON(objnr >= cachep->num);
BUG_ON(objp != index_to_obj(cachep, page, objnr));
+ set_obj_status(page, objnr, OBJECT_FREE);
if (cachep->flags & SLAB_POISON) {
#ifdef CONFIG_DEBUG_PAGEALLOC
if ((cachep->size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
@@ -2930,6 +2981,8 @@ static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
gfp_t flags, void *objp, unsigned long caller)
{
+ struct page *page;
+
if (!objp)
return objp;
if (cachep->flags & SLAB_POISON) {
@@ -2960,6 +3013,9 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
*dbg_redzone1(cachep, objp) = RED_ACTIVE;
*dbg_redzone2(cachep, objp) = RED_ACTIVE;
}
+
+ page = virt_to_head_page(objp);
+ set_obj_status(page, obj_to_index(cachep, page, objp), OBJECT_ACTIVE);
objp += obj_offset(cachep);
if (cachep->ctor && cachep->flags & SLAB_POISON)
cachep->ctor(objp);
@@ -4201,21 +4257,12 @@ static void handle_slab(unsigned long *n, struct kmem_cache *c,
struct page *page)
{
void *p;
- int i, j;
+ int i;
if (n[0] == n[1])
return;
for (i = 0, p = page->s_mem; i < c->num; i++, p += c->size) {
- bool active = true;
-
- for (j = page->active; j < c->num; j++) {
- /* Skip freed item */
- if (slab_freelist(page)[j] == i) {
- active = false;
- break;
- }
- }
- if (!active)
+ if (get_obj_status(page, i) != OBJECT_ACTIVE)
continue;
if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-13 17:48:17 +0000