diff options
| -rw-r--r-- | mm/slab.c | 57 |
1 files changed, 43 insertions, 14 deletions
diff --git a/mm/slab.c b/mm/slab.c index ff0ab772f49..1845c012739 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -292,13 +292,13 @@ struct kmem_list3 { struct list_head slabs_full; struct list_head slabs_free; unsigned long free_objects; - unsigned long next_reap; - int free_touched; unsigned int free_limit; unsigned int colour_next; /* Per-node cache coloring */ spinlock_t list_lock; struct array_cache *shared; /* shared per node */ struct array_cache **alien; /* on other nodes */ + unsigned long next_reap; /* updated without locking */ + int free_touched; /* updated without locking */ }; /* @@ -3539,6 +3539,22 @@ static void drain_array_locked(struct kmem_cache *cachep, } } + +/* + * Drain an array if it contains any elements taking the l3 lock only if + * necessary. + */ +static void drain_array(struct kmem_cache *searchp, struct kmem_list3 *l3, + struct array_cache *ac) +{ + if (ac && ac->avail) { + spin_lock_irq(&l3->list_lock); + drain_array_locked(searchp, ac, 0, + numa_node_id()); + spin_unlock_irq(&l3->list_lock); + } +} + /** * cache_reap - Reclaim memory from caches. * @unused: unused parameter @@ -3572,33 +3588,48 @@ static void cache_reap(void *unused) searchp = list_entry(walk, struct kmem_cache, next); check_irq_on(); + /* + * We only take the l3 lock if absolutely necessary and we + * have established with reasonable certainty that + * we can do some work if the lock was obtained. + */ l3 = searchp->nodelists[numa_node_id()]; + reap_alien(searchp, l3); - spin_lock_irq(&l3->list_lock); - drain_array_locked(searchp, cpu_cache_get(searchp), 0, - numa_node_id()); + drain_array(searchp, l3, cpu_cache_get(searchp)); + /* + * These are racy checks but it does not matter + * if we skip one check or scan twice. + */ if (time_after(l3->next_reap, jiffies)) - goto next_unlock; + goto next; l3->next_reap = jiffies + REAPTIMEOUT_LIST3; - if (l3->shared) - drain_array_locked(searchp, l3->shared, 0, - numa_node_id()); + drain_array(searchp, l3, l3->shared); if (l3->free_touched) { l3->free_touched = 0; - goto next_unlock; + goto next; } tofree = (l3->free_limit + 5 * searchp->num - 1) / (5 * searchp->num); do { + /* + * Do not lock if there are no free blocks. + */ + if (list_empty(&l3->slabs_free)) + break; + + spin_lock_irq(&l3->list_lock); p = l3->slabs_free.next; - if (p == &(l3->slabs_free)) + if (p == &(l3->slabs_free)) { + spin_unlock_irq(&l3->list_lock); break; + } slabp = list_entry(p, struct slab, list); BUG_ON(slabp->inuse); @@ -3613,10 +3644,8 @@ static void cache_reap(void *unused) l3->free_objects -= searchp->num; spin_unlock_irq(&l3->list_lock); slab_destroy(searchp, slabp); - spin_lock_irq(&l3->list_lock); } while (--tofree > 0); -next_unlock: - spin_unlock_irq(&l3->list_lock); +next: cond_resched(); } check_irq_on(); |