Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma

[mirror_ubuntu-artful-kernel.git] / lib / debugobjects.c

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 04c1ef717fe0c312d876a5388ae12d74d66d412b..17afb043016133f880c3c64b696b5093f28dc52e 100644 (file)
--- 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;
 }