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Merge branch 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull debugobjects updates from Ingo Molnar:
 "Misc improvements:

   - add better instrumentation/debugging

   - optimize the freeing logic improve performance"

* 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  debugobjects: Avoid another unused variable warning
  debugobjects: Fix debug_objects_freed accounting
  debugobjects: Use global free list in __debug_check_no_obj_freed()
  debugobjects: Use global free list in free_object()
  debugobjects: Add global free list and the counter
  debugobjects: Export max loops counter
This commit is contained in:
Linus Torvalds 2018-04-02 09:14:41 -07:00
parent 54dce3c35b 163cf842f5
commit 61d1757f56
1 changed files with 92 additions and 49 deletions
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141
lib/debugobjects.c
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@ -42,14 +42,18 @@ static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
static DEFINE_RAW_SPINLOCK(pool_lock);
static HLIST_HEAD(obj_pool);
static HLIST_HEAD(obj_to_free);
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;
/* 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;
static int debug_objects_fixups __read_mostly;
static int debug_objects_warnings __read_mostly;
static int debug_objects_enabled __read_mostly
@ -96,12 +100,32 @@ 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;
struct debug_obj *new, *obj;
unsigned long flags;
if (likely(obj_pool_free >= debug_objects_pool_min_level))
return;
/*
* Reuse objs from the global free list; they will be reinitialized
* when allocating.
*/
while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
raw_spin_lock_irqsave(&pool_lock, flags);
/*
* 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) {
obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
hlist_del(&obj->node);
obj_nr_tofree--;
hlist_add_head(&obj->node, &obj_pool);
obj_pool_free++;
}
raw_spin_unlock_irqrestore(&pool_lock, flags);
}
if (unlikely(!obj_cache))
return;
@ -177,39 +201,67 @@ alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
* workqueue function to free objects.
*
* To reduce contention on the global pool_lock, the actual freeing of
* debug objects will be delayed if the pool_lock is busy. We also free
* the objects in a batch of 4 for each lock/unlock cycle.
* debug objects will be delayed if the pool_lock is busy.
*/
#define ODEBUG_FREE_BATCH 4
static void free_obj_work(struct work_struct *work)
{
struct debug_obj *objs[ODEBUG_FREE_BATCH];
struct hlist_node *tmp;
struct debug_obj *obj;
unsigned long flags;
int i;
HLIST_HEAD(tofree);
if (!raw_spin_trylock_irqsave(&pool_lock, flags))
return;
while (obj_pool_free >= debug_objects_pool_size + ODEBUG_FREE_BATCH) {
for (i = 0; i < ODEBUG_FREE_BATCH; i++) {
objs[i] = hlist_entry(obj_pool.first,
typeof(*objs[0]), node);
hlist_del(&objs[i]->node);
}
obj_pool_free -= ODEBUG_FREE_BATCH;
debug_objects_freed += ODEBUG_FREE_BATCH;
/*
* We release pool_lock across kmem_cache_free() to
* avoid contention on pool_lock.
*/
raw_spin_unlock_irqrestore(&pool_lock, flags);
for (i = 0; i < ODEBUG_FREE_BATCH; i++)
kmem_cache_free(obj_cache, objs[i]);
if (!raw_spin_trylock_irqsave(&pool_lock, flags))
return;
/*
* 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
*/
while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
hlist_del(&obj->node);
hlist_add_head(&obj->node, &obj_pool);
obj_pool_free++;
obj_nr_tofree--;
}
/*
* 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
* memory outside the pool_lock held region.
*/
if (obj_nr_tofree) {
hlist_move_list(&obj_to_free, &tofree);
debug_objects_freed += obj_nr_tofree;
obj_nr_tofree = 0;
}
raw_spin_unlock_irqrestore(&pool_lock, flags);
hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
hlist_del(&obj->node);
kmem_cache_free(obj_cache, obj);
}
}
static bool __free_object(struct debug_obj *obj)
{
unsigned long flags;
bool work;
raw_spin_lock_irqsave(&pool_lock, flags);
work = (obj_pool_free > debug_objects_pool_size) && obj_cache;
obj_pool_used--;
if (work) {
obj_nr_tofree++;
hlist_add_head(&obj->node, &obj_to_free);
} else {
obj_pool_free++;
hlist_add_head(&obj->node, &obj_pool);
}
raw_spin_unlock_irqrestore(&pool_lock, flags);
return work;
}
/*
@ -218,21 +270,7 @@ static void free_obj_work(struct work_struct *work)
*/
static void free_object(struct debug_obj *obj)
{
unsigned long flags;
int sched = 0;
raw_spin_lock_irqsave(&pool_lock, flags);
/*
* schedule work when the pool is filled and the cache is
* initialized:
*/
if (obj_pool_free > debug_objects_pool_size && obj_cache)
sched = 1;
hlist_add_head(&obj->node, &obj_pool);
obj_pool_free++;
obj_pool_used--;
raw_spin_unlock_irqrestore(&pool_lock, flags);
if (sched)
if (__free_object(obj))
schedule_work(&debug_obj_work);
}
@ -714,13 +752,13 @@ EXPORT_SYMBOL_GPL(debug_object_active_state);
static void __debug_check_no_obj_freed(const void *address, unsigned long size)
{
unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
struct hlist_node *tmp;
HLIST_HEAD(freelist);
struct debug_obj_descr *descr;
enum debug_obj_state state;
struct debug_bucket *db;
struct hlist_node *tmp;
struct debug_obj *obj;
int cnt;
int cnt, objs_checked = 0;
bool work = false;
saddr = (unsigned long) address;
eaddr = saddr + size;
@ -751,21 +789,24 @@ static void __debug_check_no_obj_freed(const void *address, unsigned long size)
goto repeat;
default:
hlist_del(&obj->node);
hlist_add_head(&obj->node, &freelist);
work |= __free_object(obj);
break;
}
}
raw_spin_unlock_irqrestore(&db->lock, flags);
/* Now free them */
hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
hlist_del(&obj->node);
free_object(obj);
}
if (cnt > debug_objects_maxchain)
debug_objects_maxchain = cnt;
objs_checked += cnt;
}
if (objs_checked > debug_objects_maxchecked)
debug_objects_maxchecked = objs_checked;
/* Schedule work to actually kmem_cache_free() objects */
if (work)
schedule_work(&debug_obj_work);
}
void debug_check_no_obj_freed(const void *address, unsigned long size)
@ -780,12 +821,14 @@ void debug_check_no_obj_freed(const void *address, unsigned long size)
static int debug_stats_show(struct seq_file *m, void *v)
{
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_min_free :%d\n", obj_pool_min_free);
seq_printf(m, "pool_used :%d\n", obj_pool_used);
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);
seq_printf(m, "objs_freed :%d\n", debug_objects_freed);
return 0;