On a large SMP systems with hundreds of CPUs, the current thresholds
for allocating and freeing debug objects (256 and 1024 respectively)
may not work well. This can cause a lot of needless calls to
kmem_aloc() and kmem_free() on those systems.
To alleviate this thrashing problem, the object freeing threshold
is now increased to "1024 + # of CPUs * 32". Whereas the object
allocation threshold is increased to "256 + # of CPUs * 4". That
should make the debug objects subsystem scale better with the number
of CPUs available in the system.
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "Du Changbin" <changbin.du@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Stancek <jstancek@redhat.com>
Link: http://lkml.kernel.org/r/1483647425-4135-3-git-send-email-longman@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
static int debug_objects_warnings __read_mostly;
static int debug_objects_enabled __read_mostly
= CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
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;
/*
static struct debug_obj_descr *descr_test __read_mostly;
/*
struct debug_obj *new;
unsigned long flags;
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;
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)
new = kmem_cache_zalloc(obj_cache, gfp);
if (!new)
unsigned long flags;
raw_spin_lock_irqsave(&pool_lock, flags);
unsigned long flags;
raw_spin_lock_irqsave(&pool_lock, flags);
- while (obj_pool_free > ODEBUG_POOL_SIZE) {
+ while (obj_pool_free > debug_objects_pool_size) {
obj = hlist_entry(obj_pool.first, typeof(*obj), node);
hlist_del(&obj->node);
obj_pool_free--;
obj = hlist_entry(obj_pool.first, typeof(*obj), node);
hlist_del(&obj->node);
obj_pool_free--;
* schedule work when the pool is filled and the cache is
* initialized:
*/
* 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++;
sched = 1;
hlist_add_head(&obj->node, &obj_pool);
obj_pool_free++;
pr_warn("out of memory.\n");
} else
debug_objects_selftest();
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;