1 files changed, 47 insertions, 12 deletions

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 04c1ef717fe0..17afb0430161 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -13,6 +13,7 @@
 #include <linux/debugobjects.h>
 #include <linux/interrupt.h>
 #include <linux/sched.h>
+#include <linux/sched/task_stack.h>
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
 #include <linux/slab.h>
@@ -52,9 +53,18 @@ static int			debug_objects_fixups __read_mostly;
 static int                      debug_objects_warnings __read_mostly;
 static int                      debug_objects_enabled __read_mostly
                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
-
+static int                      debug_objects_pool_size __read_mostly
+                                = ODEBUG_POOL_SIZE;
+static int                      debug_objects_pool_min_level __read_mostly
+                                = ODEBUG_POOL_MIN_LEVEL;
 static struct debug_obj_descr   *descr_test  __read_mostly;
 
+/*
+ * Track numbers of kmem_cache_alloc()/free() calls done.
+ */
+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);
 
@@ -88,13 +98,13 @@ static void fill_pool(void)
         struct debug_obj *new;
         unsigned long flags;
 
-        if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
+        if (likely(obj_pool_free >= debug_objects_pool_min_level))
                 return;
 
         if (unlikely(!obj_cache))
                 return;
 
-        while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
+        while (obj_pool_free < debug_objects_pool_min_level) {
 
                 new = kmem_cache_zalloc(obj_cache, gfp);
                 if (!new)
@@ -102,6 +112,7 @@ static void fill_pool(void)
 
                 raw_spin_lock_irqsave(&pool_lock, flags);
                 hlist_add_head(&new->node, &obj_pool);
+                debug_objects_allocated++;
                 obj_pool_free++;
                 raw_spin_unlock_irqrestore(&pool_lock, flags);
         }
@@ -162,24 +173,39 @@ 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.
  */
+#define ODEBUG_FREE_BATCH       4
+
 static void free_obj_work(struct work_struct *work)
 {
-        struct debug_obj *obj;
+        struct debug_obj *objs[ODEBUG_FREE_BATCH];
         unsigned long flags;
+        int i;
 
-        raw_spin_lock_irqsave(&pool_lock, flags);
-        while (obj_pool_free > ODEBUG_POOL_SIZE) {
-                obj = hlist_entry(obj_pool.first, typeof(*obj), node);
-                hlist_del(&obj->node);
-                obj_pool_free--;
+        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);
-                kmem_cache_free(obj_cache, obj);
-                raw_spin_lock_irqsave(&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;
         }
         raw_spin_unlock_irqrestore(&pool_lock, flags);
 }
@@ -198,7 +224,7 @@ static void free_object(struct debug_obj *obj)
          * schedule work when the pool is filled and the cache is
          * initialized:
          */
-        if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
+        if (obj_pool_free > debug_objects_pool_size && obj_cache)
                 sched = 1;
         hlist_add_head(&obj->node, &obj_pool);
         obj_pool_free++;
@@ -758,6 +784,8 @@ static int debug_stats_show(struct seq_file *m, void *v)
         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, "objs_allocated:%d\n", debug_objects_allocated);
+        seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
         return 0;
 }
 
@@ -1116,4 +1144,11 @@ void __init debug_objects_mem_init(void)
                 pr_warn("out of memory.\n");
         } else
                 debug_objects_selftest();
+
+        /*
+         * 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;
 }