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Diffstat (limited to 'lib/debugobjects.c')
-rw-r--r--lib/debugobjects.c321
1 files changed, 253 insertions, 68 deletions
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 55437fd5128b..61261195f5b6 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -25,16 +25,37 @@
#define ODEBUG_POOL_SIZE 1024
#define ODEBUG_POOL_MIN_LEVEL 256
+#define ODEBUG_POOL_PERCPU_SIZE 64
+#define ODEBUG_BATCH_SIZE 16
#define ODEBUG_CHUNK_SHIFT PAGE_SHIFT
#define ODEBUG_CHUNK_SIZE (1 << ODEBUG_CHUNK_SHIFT)
#define ODEBUG_CHUNK_MASK (~(ODEBUG_CHUNK_SIZE - 1))
+/*
+ * We limit the freeing of debug objects via workqueue at a maximum
+ * frequency of 10Hz and about 1024 objects for each freeing operation.
+ * So it is freeing at most 10k debug objects per second.
+ */
+#define ODEBUG_FREE_WORK_MAX 1024
+#define ODEBUG_FREE_WORK_DELAY DIV_ROUND_UP(HZ, 10)
+
struct debug_bucket {
struct hlist_head list;
raw_spinlock_t lock;
};
+/*
+ * Debug object percpu free list
+ * Access is protected by disabling irq
+ */
+struct debug_percpu_free {
+ struct hlist_head free_objs;
+ int obj_free;
+};
+
+static DEFINE_PER_CPU(struct debug_percpu_free, percpu_obj_pool);
+
static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];
static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
@@ -44,13 +65,20 @@ static DEFINE_RAW_SPINLOCK(pool_lock);
static HLIST_HEAD(obj_pool);
static HLIST_HEAD(obj_to_free);
+/*
+ * Because of the presence of percpu free pools, obj_pool_free will
+ * under-count those in the percpu free pools. Similarly, obj_pool_used
+ * will over-count those in the percpu free pools. Adjustments will be
+ * made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
+ * can be off.
+ */
static int obj_pool_min_free = ODEBUG_POOL_SIZE;
static int obj_pool_free = ODEBUG_POOL_SIZE;
static int obj_pool_used;
static int obj_pool_max_used;
+static bool obj_freeing;
/* The number of objs on the global free list */
static int obj_nr_tofree;
-static struct kmem_cache *obj_cache;
static int debug_objects_maxchain __read_mostly;
static int __maybe_unused debug_objects_maxchecked __read_mostly;
@@ -63,6 +91,7 @@ static int debug_objects_pool_size __read_mostly
static int debug_objects_pool_min_level __read_mostly
= ODEBUG_POOL_MIN_LEVEL;
static struct debug_obj_descr *descr_test __read_mostly;
+static struct kmem_cache *obj_cache __read_mostly;
/*
* Track numbers of kmem_cache_alloc()/free() calls done.
@@ -71,7 +100,7 @@ static int debug_objects_allocated;
static int debug_objects_freed;
static void free_obj_work(struct work_struct *work);
-static DECLARE_WORK(debug_obj_work, free_obj_work);
+static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
static int __init enable_object_debug(char *str)
{
@@ -100,7 +129,7 @@ static const char *obj_states[ODEBUG_STATE_MAX] = {
static void fill_pool(void)
{
gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
- struct debug_obj *new, *obj;
+ struct debug_obj *obj;
unsigned long flags;
if (likely(obj_pool_free >= debug_objects_pool_min_level))
@@ -116,7 +145,7 @@ static void fill_pool(void)
* Recheck with the lock held as the worker thread might have
* won the race and freed the global free list already.
*/
- if (obj_nr_tofree) {
+ while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
hlist_del(&obj->node);
obj_nr_tofree--;
@@ -130,15 +159,23 @@ static void fill_pool(void)
return;
while (obj_pool_free < debug_objects_pool_min_level) {
+ struct debug_obj *new[ODEBUG_BATCH_SIZE];
+ int cnt;
- new = kmem_cache_zalloc(obj_cache, gfp);
- if (!new)
+ for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
+ new[cnt] = kmem_cache_zalloc(obj_cache, gfp);
+ if (!new[cnt])
+ break;
+ }
+ if (!cnt)
return;
raw_spin_lock_irqsave(&pool_lock, flags);
- hlist_add_head(&new->node, &obj_pool);
- debug_objects_allocated++;
- obj_pool_free++;
+ while (cnt) {
+ hlist_add_head(&new[--cnt]->node, &obj_pool);
+ debug_objects_allocated++;
+ obj_pool_free++;
+ }
raw_spin_unlock_irqrestore(&pool_lock, flags);
}
}
@@ -163,36 +200,81 @@ static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
}
/*
+ * Allocate a new object from the hlist
+ */
+static struct debug_obj *__alloc_object(struct hlist_head *list)
+{
+ struct debug_obj *obj = NULL;
+
+ if (list->first) {
+ obj = hlist_entry(list->first, typeof(*obj), node);
+ hlist_del(&obj->node);
+ }
+
+ return obj;
+}
+
+/*
* Allocate a new object. If the pool is empty, switch off the debugger.
* Must be called with interrupts disabled.
*/
static struct debug_obj *
alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
{
- struct debug_obj *obj = NULL;
+ struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
+ struct debug_obj *obj;
- raw_spin_lock(&pool_lock);
- if (obj_pool.first) {
- obj = hlist_entry(obj_pool.first, typeof(*obj), node);
+ if (likely(obj_cache)) {
+ obj = __alloc_object(&percpu_pool->free_objs);
+ if (obj) {
+ percpu_pool->obj_free--;
+ goto init_obj;
+ }
+ }
- obj->object = addr;
- obj->descr = descr;
- obj->state = ODEBUG_STATE_NONE;
- obj->astate = 0;
- hlist_del(&obj->node);
+ raw_spin_lock(&pool_lock);
+ obj = __alloc_object(&obj_pool);
+ if (obj) {
+ obj_pool_used++;
+ obj_pool_free--;
- hlist_add_head(&obj->node, &b->list);
+ /*
+ * Looking ahead, allocate one batch of debug objects and
+ * put them into the percpu free pool.
+ */
+ if (likely(obj_cache)) {
+ int i;
+
+ for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
+ struct debug_obj *obj2;
+
+ obj2 = __alloc_object(&obj_pool);
+ if (!obj2)
+ break;
+ hlist_add_head(&obj2->node,
+ &percpu_pool->free_objs);
+ percpu_pool->obj_free++;
+ obj_pool_used++;
+ obj_pool_free--;
+ }
+ }
- obj_pool_used++;
if (obj_pool_used > obj_pool_max_used)
obj_pool_max_used = obj_pool_used;
- obj_pool_free--;
if (obj_pool_free < obj_pool_min_free)
obj_pool_min_free = obj_pool_free;
}
raw_spin_unlock(&pool_lock);
+init_obj:
+ if (obj) {
+ obj->object = addr;
+ obj->descr = descr;
+ obj->state = ODEBUG_STATE_NONE;
+ obj->astate = 0;
+ hlist_add_head(&obj->node, &b->list);
+ }
return obj;
}
@@ -209,13 +291,19 @@ static void free_obj_work(struct work_struct *work)
unsigned long flags;
HLIST_HEAD(tofree);
+ WRITE_ONCE(obj_freeing, false);
if (!raw_spin_trylock_irqsave(&pool_lock, flags))
return;
+ if (obj_pool_free >= debug_objects_pool_size)
+ goto free_objs;
+
/*
* The objs on the pool list might be allocated before the work is
* run, so recheck if pool list it full or not, if not fill pool
- * list from the global free list
+ * list from the global free list. As it is likely that a workload
+ * may be gearing up to use more and more objects, don't free any
+ * of them until the next round.
*/
while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
@@ -224,7 +312,10 @@ static void free_obj_work(struct work_struct *work)
obj_pool_free++;
obj_nr_tofree--;
}
+ raw_spin_unlock_irqrestore(&pool_lock, flags);
+ return;
+free_objs:
/*
* Pool list is already full and there are still objs on the free
* list. Move remaining free objs to a temporary list to free the
@@ -243,24 +334,86 @@ static void free_obj_work(struct work_struct *work)
}
}
-static bool __free_object(struct debug_obj *obj)
+static void __free_object(struct debug_obj *obj)
{
+ struct debug_obj *objs[ODEBUG_BATCH_SIZE];
+ struct debug_percpu_free *percpu_pool;
+ int lookahead_count = 0;
unsigned long flags;
bool work;
- raw_spin_lock_irqsave(&pool_lock, flags);
- work = (obj_pool_free > debug_objects_pool_size) && obj_cache;
+ local_irq_save(flags);
+ if (!obj_cache)
+ goto free_to_obj_pool;
+
+ /*
+ * Try to free it into the percpu pool first.
+ */
+ percpu_pool = this_cpu_ptr(&percpu_obj_pool);
+ if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
+ hlist_add_head(&obj->node, &percpu_pool->free_objs);
+ percpu_pool->obj_free++;
+ local_irq_restore(flags);
+ return;
+ }
+
+ /*
+ * As the percpu pool is full, look ahead and pull out a batch
+ * of objects from the percpu pool and free them as well.
+ */
+ for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
+ objs[lookahead_count] = __alloc_object(&percpu_pool->free_objs);
+ if (!objs[lookahead_count])
+ break;
+ percpu_pool->obj_free--;
+ }
+
+free_to_obj_pool:
+ raw_spin_lock(&pool_lock);
+ work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
+ (obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
obj_pool_used--;
if (work) {
obj_nr_tofree++;
hlist_add_head(&obj->node, &obj_to_free);
+ if (lookahead_count) {
+ obj_nr_tofree += lookahead_count;
+ obj_pool_used -= lookahead_count;
+ while (lookahead_count) {
+ hlist_add_head(&objs[--lookahead_count]->node,
+ &obj_to_free);
+ }
+ }
+
+ if ((obj_pool_free > debug_objects_pool_size) &&
+ (obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
+ int i;
+
+ /*
+ * Free one more batch of objects from obj_pool.
+ */
+ for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
+ obj = __alloc_object(&obj_pool);
+ hlist_add_head(&obj->node, &obj_to_free);
+ obj_pool_free--;
+ obj_nr_tofree++;
+ }
+ }
} else {
obj_pool_free++;
hlist_add_head(&obj->node, &obj_pool);
+ if (lookahead_count) {
+ obj_pool_free += lookahead_count;
+ obj_pool_used -= lookahead_count;
+ while (lookahead_count) {
+ hlist_add_head(&objs[--lookahead_count]->node,
+ &obj_pool);
+ }
+ }
}
- raw_spin_unlock_irqrestore(&pool_lock, flags);
- return work;
+ raw_spin_unlock(&pool_lock);
+ local_irq_restore(flags);
}
/*
@@ -269,8 +422,11 @@ static bool __free_object(struct debug_obj *obj)
*/
static void free_object(struct debug_obj *obj)
{
- if (__free_object(obj))
- schedule_work(&debug_obj_work);
+ __free_object(obj);
+ if (!obj_freeing && obj_nr_tofree) {
+ WRITE_ONCE(obj_freeing, true);
+ schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
+ }
}
/*
@@ -372,6 +528,7 @@ static void
__debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
{
enum debug_obj_state state;
+ bool check_stack = false;
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
@@ -391,7 +548,7 @@ __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
debug_objects_oom();
return;
}
- debug_object_is_on_stack(addr, onstack);
+ check_stack = true;
}
switch (obj->state) {
@@ -402,20 +559,23 @@ __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
break;
case ODEBUG_STATE_ACTIVE:
- debug_print_object(obj, "init");
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
+ debug_print_object(obj, "init");
debug_object_fixup(descr->fixup_init, addr, state);
return;
case ODEBUG_STATE_DESTROYED:
+ raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(obj, "init");
- break;
+ return;
default:
break;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
+ if (check_stack)
+ debug_object_is_on_stack(addr, onstack);
}
/**
@@ -473,6 +633,8 @@ int debug_object_activate(void *addr, struct debug_obj_descr *descr)
obj = lookup_object(addr, db);
if (obj) {
+ bool print_object = false;
+
switch (obj->state) {
case ODEBUG_STATE_INIT:
case ODEBUG_STATE_INACTIVE:
@@ -481,14 +643,14 @@ int debug_object_activate(void *addr, struct debug_obj_descr *descr)
break;
case ODEBUG_STATE_ACTIVE:
- debug_print_object(obj, "activate");
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
+ debug_print_object(obj, "activate");
ret = debug_object_fixup(descr->fixup_activate, addr, state);
return ret ? 0 : -EINVAL;
case ODEBUG_STATE_DESTROYED:
- debug_print_object(obj, "activate");
+ print_object = true;
ret = -EINVAL;
break;
default:
@@ -496,10 +658,13 @@ int debug_object_activate(void *addr, struct debug_obj_descr *descr)
break;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
+ if (print_object)
+ debug_print_object(obj, "activate");
return ret;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
+
/*
* We are here when a static object is activated. We
* let the type specific code confirm whether this is
@@ -531,6 +696,7 @@ void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
+ bool print_object = false;
if (!debug_objects_enabled)
return;
@@ -548,24 +714,27 @@ void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
if (!obj->astate)
obj->state = ODEBUG_STATE_INACTIVE;
else
- debug_print_object(obj, "deactivate");
+ print_object = true;
break;
case ODEBUG_STATE_DESTROYED:
- debug_print_object(obj, "deactivate");
+ print_object = true;
break;
default:
break;
}
- } else {
+ }
+
+ raw_spin_unlock_irqrestore(&db->lock, flags);
+ if (!obj) {
struct debug_obj o = { .object = addr,
.state = ODEBUG_STATE_NOTAVAILABLE,
.descr = descr };
debug_print_object(&o, "deactivate");
+ } else if (print_object) {
+ debug_print_object(obj, "deactivate");
}
-
- raw_spin_unlock_irqrestore(&db->lock, flags);
}
EXPORT_SYMBOL_GPL(debug_object_deactivate);
@@ -580,6 +749,7 @@ void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
+ bool print_object = false;
if (!debug_objects_enabled)
return;
@@ -599,20 +769,22 @@ void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
obj->state = ODEBUG_STATE_DESTROYED;
break;
case ODEBUG_STATE_ACTIVE:
- debug_print_object(obj, "destroy");
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
+ debug_print_object(obj, "destroy");
debug_object_fixup(descr->fixup_destroy, addr, state);
return;
case ODEBUG_STATE_DESTROYED:
- debug_print_object(obj, "destroy");
+ print_object = true;
break;
default:
break;
}
out_unlock:
raw_spin_unlock_irqrestore(&db->lock, flags);
+ if (print_object)
+ debug_print_object(obj, "destroy");
}
EXPORT_SYMBOL_GPL(debug_object_destroy);
@@ -641,9 +813,9 @@ void debug_object_free(void *addr, struct debug_obj_descr *descr)
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
- debug_print_object(obj, "free");
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
+ debug_print_object(obj, "free");
debug_object_fixup(descr->fixup_free, addr, state);
return;
default:
@@ -716,6 +888,7 @@ debug_object_active_state(void *addr, struct debug_obj_descr *descr,
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
+ bool print_object = false;
if (!debug_objects_enabled)
return;
@@ -731,22 +904,25 @@ debug_object_active_state(void *addr, struct debug_obj_descr *descr,
if (obj->astate == expect)
obj->astate = next;
else
- debug_print_object(obj, "active_state");
+ print_object = true;
break;
default:
- debug_print_object(obj, "active_state");
+ print_object = true;
break;
}
- } else {
+ }
+
+ raw_spin_unlock_irqrestore(&db->lock, flags);
+ if (!obj) {
struct debug_obj o = { .object = addr,
.state = ODEBUG_STATE_NOTAVAILABLE,
.descr = descr };
debug_print_object(&o, "active_state");
+ } else if (print_object) {
+ debug_print_object(obj, "active_state");
}
-
- raw_spin_unlock_irqrestore(&db->lock, flags);
}
EXPORT_SYMBOL_GPL(debug_object_active_state);
@@ -760,7 +936,6 @@ static void __debug_check_no_obj_freed(const void *address, unsigned long size)
struct hlist_node *tmp;
struct debug_obj *obj;
int cnt, objs_checked = 0;
- bool work = false;
saddr = (unsigned long) address;
eaddr = saddr + size;
@@ -782,16 +957,16 @@ repeat:
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
- debug_print_object(obj, "free");
descr = obj->descr;
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
+ debug_print_object(obj, "free");
debug_object_fixup(descr->fixup_free,
(void *) oaddr, state);
goto repeat;
default:
hlist_del(&obj->node);
- work |= __free_object(obj);
+ __free_object(obj);
break;
}
}
@@ -807,8 +982,10 @@ repeat:
debug_objects_maxchecked = objs_checked;
/* Schedule work to actually kmem_cache_free() objects */
- if (work)
- schedule_work(&debug_obj_work);
+ if (!obj_freeing && obj_nr_tofree) {
+ WRITE_ONCE(obj_freeing, true);
+ schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
+ }
}
void debug_check_no_obj_freed(const void *address, unsigned long size)
@@ -822,13 +999,19 @@ void debug_check_no_obj_freed(const void *address, unsigned long size)
static int debug_stats_show(struct seq_file *m, void *v)
{
+ int cpu, obj_percpu_free = 0;
+
+ for_each_possible_cpu(cpu)
+ obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
+
seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
seq_printf(m, "max_checked :%d\n", debug_objects_maxchecked);
seq_printf(m, "warnings :%d\n", debug_objects_warnings);
seq_printf(m, "fixups :%d\n", debug_objects_fixups);
- seq_printf(m, "pool_free :%d\n", obj_pool_free);
+ seq_printf(m, "pool_free :%d\n", obj_pool_free + obj_percpu_free);
+ seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
- seq_printf(m, "pool_used :%d\n", obj_pool_used);
+ seq_printf(m, "pool_used :%d\n", obj_pool_used - obj_percpu_free);
seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
seq_printf(m, "on_free_list :%d\n", obj_nr_tofree);
seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
@@ -850,26 +1033,16 @@ static const struct file_operations debug_stats_fops = {
static int __init debug_objects_init_debugfs(void)
{
- struct dentry *dbgdir, *dbgstats;
+ struct dentry *dbgdir;
if (!debug_objects_enabled)
return 0;
dbgdir = debugfs_create_dir("debug_objects", NULL);
- if (!dbgdir)
- return -ENOMEM;
- dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
- &debug_stats_fops);
- if (!dbgstats)
- goto err;
+ debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
return 0;
-
-err:
- debugfs_remove(dbgdir);
-
- return -ENOMEM;
}
__initcall(debug_objects_init_debugfs);
@@ -1175,9 +1348,20 @@ free:
*/
void __init debug_objects_mem_init(void)
{
+ int cpu, extras;
+
if (!debug_objects_enabled)
return;
+ /*
+ * Initialize the percpu object pools
+ *
+ * Initialization is not strictly necessary, but was done for
+ * completeness.
+ */
+ for_each_possible_cpu(cpu)
+ INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
+
obj_cache = kmem_cache_create("debug_objects_cache",
sizeof (struct debug_obj), 0,
SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
@@ -1194,6 +1378,7 @@ void __init debug_objects_mem_init(void)
* Increase the thresholds for allocating and freeing objects
* according to the number of possible CPUs available in the system.
*/
- debug_objects_pool_size += num_possible_cpus() * 32;
- debug_objects_pool_min_level += num_possible_cpus() * 4;
+ extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
+ debug_objects_pool_size += extras;
+ debug_objects_pool_min_level += extras;
}
generated by cgit v1.2.3 (git 2.39.0) at 2025-10-31 11:29:12 +0300