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-rw-r--r--mm/slub.c244
1 files changed, 175 insertions, 69 deletions
diff --git a/mm/slub.c b/mm/slub.c
index a0c1365f6426..46997517406e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1065,11 +1065,15 @@ bad:
return 0;
}
+/* Supports checking bulk free of a constructed freelist */
static noinline struct kmem_cache_node *free_debug_processing(
- struct kmem_cache *s, struct page *page, void *object,
+ struct kmem_cache *s, struct page *page,
+ void *head, void *tail, int bulk_cnt,
unsigned long addr, unsigned long *flags)
{
struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+ void *object = head;
+ int cnt = 0;
spin_lock_irqsave(&n->list_lock, *flags);
slab_lock(page);
@@ -1077,6 +1081,9 @@ static noinline struct kmem_cache_node *free_debug_processing(
if (!check_slab(s, page))
goto fail;
+next_object:
+ cnt++;
+
if (!check_valid_pointer(s, page, object)) {
slab_err(s, page, "Invalid object pointer 0x%p", object);
goto fail;
@@ -1107,8 +1114,19 @@ static noinline struct kmem_cache_node *free_debug_processing(
if (s->flags & SLAB_STORE_USER)
set_track(s, object, TRACK_FREE, addr);
trace(s, page, object, 0);
+ /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
init_object(s, object, SLUB_RED_INACTIVE);
+
+ /* Reached end of constructed freelist yet? */
+ if (object != tail) {
+ object = get_freepointer(s, object);
+ goto next_object;
+ }
out:
+ if (cnt != bulk_cnt)
+ slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
+ bulk_cnt, cnt);
+
slab_unlock(page);
/*
* Keep node_lock to preserve integrity
@@ -1212,7 +1230,8 @@ static inline int alloc_debug_processing(struct kmem_cache *s,
struct page *page, void *object, unsigned long addr) { return 0; }
static inline struct kmem_cache_node *free_debug_processing(
- struct kmem_cache *s, struct page *page, void *object,
+ struct kmem_cache *s, struct page *page,
+ void *head, void *tail, int bulk_cnt,
unsigned long addr, unsigned long *flags) { return NULL; }
static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
@@ -1273,14 +1292,21 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
return memcg_kmem_get_cache(s, flags);
}
-static inline void slab_post_alloc_hook(struct kmem_cache *s,
- gfp_t flags, void *object)
+static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
+ size_t size, void **p)
{
+ size_t i;
+
flags &= gfp_allowed_mask;
- kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
- kmemleak_alloc_recursive(object, s->object_size, 1, s->flags, flags);
+ for (i = 0; i < size; i++) {
+ void *object = p[i];
+
+ kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
+ kmemleak_alloc_recursive(object, s->object_size, 1,
+ s->flags, flags);
+ kasan_slab_alloc(s, object);
+ }
memcg_kmem_put_cache(s);
- kasan_slab_alloc(s, object);
}
static inline void slab_free_hook(struct kmem_cache *s, void *x)
@@ -1308,6 +1334,29 @@ static inline void slab_free_hook(struct kmem_cache *s, void *x)
kasan_slab_free(s, x);
}
+static inline void slab_free_freelist_hook(struct kmem_cache *s,
+ void *head, void *tail)
+{
+/*
+ * Compiler cannot detect this function can be removed if slab_free_hook()
+ * evaluates to nothing. Thus, catch all relevant config debug options here.
+ */
+#if defined(CONFIG_KMEMCHECK) || \
+ defined(CONFIG_LOCKDEP) || \
+ defined(CONFIG_DEBUG_KMEMLEAK) || \
+ defined(CONFIG_DEBUG_OBJECTS_FREE) || \
+ defined(CONFIG_KASAN)
+
+ void *object = head;
+ void *tail_obj = tail ? : head;
+
+ do {
+ slab_free_hook(s, object);
+ } while ((object != tail_obj) &&
+ (object = get_freepointer(s, object)));
+#endif
+}
+
static void setup_object(struct kmem_cache *s, struct page *page,
void *object)
{
@@ -2433,7 +2482,7 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
static __always_inline void *slab_alloc_node(struct kmem_cache *s,
gfp_t gfpflags, int node, unsigned long addr)
{
- void **object;
+ void *object;
struct kmem_cache_cpu *c;
struct page *page;
unsigned long tid;
@@ -2512,7 +2561,7 @@ redo:
if (unlikely(gfpflags & __GFP_ZERO) && object)
memset(object, 0, s->object_size);
- slab_post_alloc_hook(s, gfpflags, object);
+ slab_post_alloc_hook(s, gfpflags, 1, &object);
return object;
}
@@ -2583,10 +2632,11 @@ EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
* handling required then we can return immediately.
*/
static void __slab_free(struct kmem_cache *s, struct page *page,
- void *x, unsigned long addr)
+ void *head, void *tail, int cnt,
+ unsigned long addr)
+
{
void *prior;
- void **object = (void *)x;
int was_frozen;
struct page new;
unsigned long counters;
@@ -2596,7 +2646,8 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
stat(s, FREE_SLOWPATH);
if (kmem_cache_debug(s) &&
- !(n = free_debug_processing(s, page, x, addr, &flags)))
+ !(n = free_debug_processing(s, page, head, tail, cnt,
+ addr, &flags)))
return;
do {
@@ -2606,10 +2657,10 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
}
prior = page->freelist;
counters = page->counters;
- set_freepointer(s, object, prior);
+ set_freepointer(s, tail, prior);
new.counters = counters;
was_frozen = new.frozen;
- new.inuse--;
+ new.inuse -= cnt;
if ((!new.inuse || !prior) && !was_frozen) {
if (kmem_cache_has_cpu_partial(s) && !prior) {
@@ -2640,7 +2691,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
} while (!cmpxchg_double_slab(s, page,
prior, counters,
- object, new.counters,
+ head, new.counters,
"__slab_free"));
if (likely(!n)) {
@@ -2705,15 +2756,20 @@ slab_empty:
*
* If fastpath is not possible then fall back to __slab_free where we deal
* with all sorts of special processing.
+ *
+ * Bulk free of a freelist with several objects (all pointing to the
+ * same page) possible by specifying head and tail ptr, plus objects
+ * count (cnt). Bulk free indicated by tail pointer being set.
*/
-static __always_inline void slab_free(struct kmem_cache *s,
- struct page *page, void *x, unsigned long addr)
+static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
+ void *head, void *tail, int cnt,
+ unsigned long addr)
{
- void **object = (void *)x;
+ void *tail_obj = tail ? : head;
struct kmem_cache_cpu *c;
unsigned long tid;
- slab_free_hook(s, x);
+ slab_free_freelist_hook(s, head, tail);
redo:
/*
@@ -2732,19 +2788,19 @@ redo:
barrier();
if (likely(page == c->page)) {
- set_freepointer(s, object, c->freelist);
+ set_freepointer(s, tail_obj, c->freelist);
if (unlikely(!this_cpu_cmpxchg_double(
s->cpu_slab->freelist, s->cpu_slab->tid,
c->freelist, tid,
- object, next_tid(tid)))) {
+ head, next_tid(tid)))) {
note_cmpxchg_failure("slab_free", s, tid);
goto redo;
}
stat(s, FREE_FASTPATH);
} else
- __slab_free(s, page, x, addr);
+ __slab_free(s, page, head, tail_obj, cnt, addr);
}
@@ -2753,59 +2809,116 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
s = cache_from_obj(s, x);
if (!s)
return;
- slab_free(s, virt_to_head_page(x), x, _RET_IP_);
+ slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
trace_kmem_cache_free(_RET_IP_, x);
}
EXPORT_SYMBOL(kmem_cache_free);
-/* Note that interrupts must be enabled when calling this function. */
-void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
-{
- struct kmem_cache_cpu *c;
+struct detached_freelist {
struct page *page;
- int i;
+ void *tail;
+ void *freelist;
+ int cnt;
+};
- local_irq_disable();
- c = this_cpu_ptr(s->cpu_slab);
+/*
+ * This function progressively scans the array with free objects (with
+ * a limited look ahead) and extract objects belonging to the same
+ * page. It builds a detached freelist directly within the given
+ * page/objects. This can happen without any need for
+ * synchronization, because the objects are owned by running process.
+ * The freelist is build up as a single linked list in the objects.
+ * The idea is, that this detached freelist can then be bulk
+ * transferred to the real freelist(s), but only requiring a single
+ * synchronization primitive. Look ahead in the array is limited due
+ * to performance reasons.
+ */
+static int build_detached_freelist(struct kmem_cache *s, size_t size,
+ void **p, struct detached_freelist *df)
+{
+ size_t first_skipped_index = 0;
+ int lookahead = 3;
+ void *object;
- for (i = 0; i < size; i++) {
- void *object = p[i];
+ /* Always re-init detached_freelist */
+ df->page = NULL;
- BUG_ON(!object);
- /* kmem cache debug support */
- s = cache_from_obj(s, object);
- if (unlikely(!s))
- goto exit;
- slab_free_hook(s, object);
+ do {
+ object = p[--size];
+ } while (!object && size);
- page = virt_to_head_page(object);
+ if (!object)
+ return 0;
- if (c->page == page) {
- /* Fastpath: local CPU free */
- set_freepointer(s, object, c->freelist);
- c->freelist = object;
- } else {
- c->tid = next_tid(c->tid);
- local_irq_enable();
- /* Slowpath: overhead locked cmpxchg_double_slab */
- __slab_free(s, page, object, _RET_IP_);
- local_irq_disable();
- c = this_cpu_ptr(s->cpu_slab);
+ /* Start new detached freelist */
+ set_freepointer(s, object, NULL);
+ df->page = virt_to_head_page(object);
+ df->tail = object;
+ df->freelist = object;
+ p[size] = NULL; /* mark object processed */
+ df->cnt = 1;
+
+ while (size) {
+ object = p[--size];
+ if (!object)
+ continue; /* Skip processed objects */
+
+ /* df->page is always set at this point */
+ if (df->page == virt_to_head_page(object)) {
+ /* Opportunity build freelist */
+ set_freepointer(s, object, df->freelist);
+ df->freelist = object;
+ df->cnt++;
+ p[size] = NULL; /* mark object processed */
+
+ continue;
}
+
+ /* Limit look ahead search */
+ if (!--lookahead)
+ break;
+
+ if (!first_skipped_index)
+ first_skipped_index = size + 1;
}
-exit:
- c->tid = next_tid(c->tid);
- local_irq_enable();
+
+ return first_skipped_index;
+}
+
+
+/* Note that interrupts must be enabled when calling this function. */
+void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p)
+{
+ if (WARN_ON(!size))
+ return;
+
+ do {
+ struct detached_freelist df;
+ struct kmem_cache *s;
+
+ /* Support for memcg */
+ s = cache_from_obj(orig_s, p[size - 1]);
+
+ size = build_detached_freelist(s, size, p, &df);
+ if (unlikely(!df.page))
+ continue;
+
+ slab_free(s, df.page, df.freelist, df.tail, df.cnt, _RET_IP_);
+ } while (likely(size));
}
EXPORT_SYMBOL(kmem_cache_free_bulk);
/* Note that interrupts must be enabled when calling this function. */
-bool kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
- void **p)
+int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
+ void **p)
{
struct kmem_cache_cpu *c;
int i;
+ /* memcg and kmem_cache debug support */
+ s = slab_pre_alloc_hook(s, flags);
+ if (unlikely(!s))
+ return false;
/*
* Drain objects in the per cpu slab, while disabling local
* IRQs, which protects against PREEMPT and interrupts
@@ -2830,17 +2943,8 @@ bool kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
c = this_cpu_ptr(s->cpu_slab);
continue; /* goto for-loop */
}
-
- /* kmem_cache debug support */
- s = slab_pre_alloc_hook(s, flags);
- if (unlikely(!s))
- goto error;
-
c->freelist = get_freepointer(s, object);
p[i] = object;
-
- /* kmem_cache debug support */
- slab_post_alloc_hook(s, flags, object);
}
c->tid = next_tid(c->tid);
local_irq_enable();
@@ -2853,12 +2957,14 @@ bool kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
memset(p[j], 0, s->object_size);
}
- return true;
-
+ /* memcg and kmem_cache debug support */
+ slab_post_alloc_hook(s, flags, size, p);
+ return i;
error:
- __kmem_cache_free_bulk(s, i, p);
local_irq_enable();
- return false;
+ slab_post_alloc_hook(s, flags, i, p);
+ __kmem_cache_free_bulk(s, i, p);
+ return 0;
}
EXPORT_SYMBOL(kmem_cache_alloc_bulk);
@@ -3523,7 +3629,7 @@ void kfree(const void *x)
__free_kmem_pages(page, compound_order(page));
return;
}
- slab_free(page->slab_cache, page, object, _RET_IP_);
+ slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
}
EXPORT_SYMBOL(kfree);