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authorWaiman Long <longman@redhat.com>2017-01-05 23:17:04 +0300
committerThomas Gleixner <tglx@linutronix.de>2017-02-04 11:01:55 +0300
commit97dd552eb23c83dbf626a6e84666c7e281375d47 (patch)
treea9a5358b76f201f915051d42ea5e1358a93ab9c0 /lib
parentc4b73aabd0989d93b82894417ae501690bd1db5e (diff)
downloadlinux-97dd552eb23c83dbf626a6e84666c7e281375d47.tar.xz
debugobjects: Scale thresholds with # of CPUs
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>
Diffstat (limited to 'lib')
-rw-r--r--lib/debugobjects.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index d78673e7dc56..dc78217b2199 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -52,7 +52,10 @@ 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;
/*
@@ -94,13 +97,13 @@ 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)
@@ -176,7 +179,7 @@ static void free_obj_work(struct work_struct *work)
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--;
@@ -206,7 +209,7 @@ 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++;
@@ -1126,4 +1129,11 @@ 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;
}