From d26bf5056fc087d845bfbb8b651b4be2933ab7a6 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Mon, 20 May 2019 10:14:48 -0400 Subject: [PATCH] debugobjects: Reduce number of pool_lock acquisitions in fill_pool() In fill_pool(), the pool_lock is acquired and then released once per debug object. If many objects are to be filled, the constant lock and unlock operations are extra overhead. To reduce the overhead, batch them up and do an allocation of 4 objects per lock/unlock sequence. Signed-off-by: Waiman Long Signed-off-by: Thomas Gleixner Cc: Andrew Morton Cc: Yang Shi Cc: "Joel Fernandes (Google)" Cc: Qian Cai Cc: Zhong Jiang Link: https://lkml.kernel.org/r/20190520141450.7575-4-longman@redhat.com --- lib/debugobjects.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 714459a8dc10..7ea19fa63561 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -120,7 +120,7 @@ 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, *obj; + struct debug_obj *obj; unsigned long flags; if (likely(obj_pool_free >= debug_objects_pool_min_level)) @@ -136,7 +136,7 @@ static void fill_pool(void) * 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) { + while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) { obj = hlist_entry(obj_to_free.first, typeof(*obj), node); hlist_del(&obj->node); obj_nr_tofree--; @@ -150,15 +150,23 @@ static void fill_pool(void) return; while (obj_pool_free < debug_objects_pool_min_level) { + struct debug_obj *new[ODEBUG_BATCH_SIZE]; + int cnt; - new = kmem_cache_zalloc(obj_cache, gfp); - if (!new) + for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) { + new[cnt] = kmem_cache_zalloc(obj_cache, gfp); + if (!new[cnt]) + break; + } + if (!cnt) return; raw_spin_lock_irqsave(&pool_lock, flags); - hlist_add_head(&new->node, &obj_pool); - debug_objects_allocated++; - obj_pool_free++; + while (cnt) { + hlist_add_head(&new[--cnt]->node, &obj_pool); + debug_objects_allocated++; + obj_pool_free++; + } raw_spin_unlock_irqrestore(&pool_lock, flags); } } @@ -280,7 +288,7 @@ static void free_obj_work(struct work_struct *work) /* * 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 + * 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);