From 18004c5d4084d965aa1396392706b8688306427a Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Fri, 6 Jul 2012 15:25:12 -0500 Subject: mm, sl[aou]b: Use a common mutex definition Use the mutex definition from SLAB and make it the common way to take a sleeping lock. This has the effect of using a mutex instead of a rw semaphore for SLUB. SLOB gains the use of a mutex for kmem_cache_create serialization. Not needed now but SLOB may acquire some more features later (like slabinfo / sysfs support) through the expansion of the common code that will need this. Reviewed-by: Glauber Costa Reviewed-by: Joonsoo Kim Signed-off-by: Christoph Lameter Signed-off-by: Pekka Enberg --- mm/slub.c | 54 +++++++++++++++++++++++++----------------------------- 1 file changed, 25 insertions(+), 29 deletions(-) (limited to 'mm/slub.c') diff --git a/mm/slub.c b/mm/slub.c index 4c385164..8c4fd37 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -36,13 +36,13 @@ /* * Lock order: - * 1. slub_lock (Global Semaphore) + * 1. slab_mutex (Global Mutex) * 2. node->list_lock * 3. slab_lock(page) (Only on some arches and for debugging) * - * slub_lock + * slab_mutex * - * The role of the slub_lock is to protect the list of all the slabs + * The role of the slab_mutex is to protect the list of all the slabs * and to synchronize major metadata changes to slab cache structures. * * The slab_lock is only used for debugging and on arches that do not @@ -183,10 +183,6 @@ static int kmem_size = sizeof(struct kmem_cache); static struct notifier_block slab_notifier; #endif -/* A list of all slab caches on the system */ -static DECLARE_RWSEM(slub_lock); -static LIST_HEAD(slab_caches); - /* * Tracking user of a slab. */ @@ -3177,11 +3173,11 @@ static inline int kmem_cache_close(struct kmem_cache *s) */ void kmem_cache_destroy(struct kmem_cache *s) { - down_write(&slub_lock); + mutex_lock(&slab_mutex); s->refcount--; if (!s->refcount) { list_del(&s->list); - up_write(&slub_lock); + mutex_unlock(&slab_mutex); if (kmem_cache_close(s)) { printk(KERN_ERR "SLUB %s: %s called for cache that " "still has objects.\n", s->name, __func__); @@ -3191,7 +3187,7 @@ void kmem_cache_destroy(struct kmem_cache *s) rcu_barrier(); sysfs_slab_remove(s); } else - up_write(&slub_lock); + mutex_unlock(&slab_mutex); } EXPORT_SYMBOL(kmem_cache_destroy); @@ -3253,7 +3249,7 @@ static struct kmem_cache *__init create_kmalloc_cache(const char *name, /* * This function is called with IRQs disabled during early-boot on - * single CPU so there's no need to take slub_lock here. + * single CPU so there's no need to take slab_mutex here. */ if (!kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN, flags, NULL)) @@ -3538,10 +3534,10 @@ static int slab_mem_going_offline_callback(void *arg) { struct kmem_cache *s; - down_read(&slub_lock); + mutex_lock(&slab_mutex); list_for_each_entry(s, &slab_caches, list) kmem_cache_shrink(s); - up_read(&slub_lock); + mutex_unlock(&slab_mutex); return 0; } @@ -3562,7 +3558,7 @@ static void slab_mem_offline_callback(void *arg) if (offline_node < 0) return; - down_read(&slub_lock); + mutex_lock(&slab_mutex); list_for_each_entry(s, &slab_caches, list) { n = get_node(s, offline_node); if (n) { @@ -3578,7 +3574,7 @@ static void slab_mem_offline_callback(void *arg) kmem_cache_free(kmem_cache_node, n); } } - up_read(&slub_lock); + mutex_unlock(&slab_mutex); } static int slab_mem_going_online_callback(void *arg) @@ -3601,7 +3597,7 @@ static int slab_mem_going_online_callback(void *arg) * allocate a kmem_cache_node structure in order to bring the node * online. */ - down_read(&slub_lock); + mutex_lock(&slab_mutex); list_for_each_entry(s, &slab_caches, list) { /* * XXX: kmem_cache_alloc_node will fallback to other nodes @@ -3617,7 +3613,7 @@ static int slab_mem_going_online_callback(void *arg) s->node[nid] = n; } out: - up_read(&slub_lock); + mutex_unlock(&slab_mutex); return ret; } @@ -3915,7 +3911,7 @@ struct kmem_cache *__kmem_cache_create(const char *name, size_t size, struct kmem_cache *s; char *n; - down_write(&slub_lock); + mutex_lock(&slab_mutex); s = find_mergeable(size, align, flags, name, ctor); if (s) { s->refcount++; @@ -3930,7 +3926,7 @@ struct kmem_cache *__kmem_cache_create(const char *name, size_t size, s->refcount--; goto err; } - up_write(&slub_lock); + mutex_unlock(&slab_mutex); return s; } @@ -3943,9 +3939,9 @@ struct kmem_cache *__kmem_cache_create(const char *name, size_t size, if (kmem_cache_open(s, n, size, align, flags, ctor)) { list_add(&s->list, &slab_caches); - up_write(&slub_lock); + mutex_unlock(&slab_mutex); if (sysfs_slab_add(s)) { - down_write(&slub_lock); + mutex_lock(&slab_mutex); list_del(&s->list); kfree(n); kfree(s); @@ -3957,7 +3953,7 @@ struct kmem_cache *__kmem_cache_create(const char *name, size_t size, } kfree(n); err: - up_write(&slub_lock); + mutex_unlock(&slab_mutex); return s; } @@ -3978,13 +3974,13 @@ static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb, case CPU_UP_CANCELED_FROZEN: case CPU_DEAD: case CPU_DEAD_FROZEN: - down_read(&slub_lock); + mutex_lock(&slab_mutex); list_for_each_entry(s, &slab_caches, list) { local_irq_save(flags); __flush_cpu_slab(s, cpu); local_irq_restore(flags); } - up_read(&slub_lock); + mutex_unlock(&slab_mutex); break; default: break; @@ -5360,11 +5356,11 @@ static int __init slab_sysfs_init(void) struct kmem_cache *s; int err; - down_write(&slub_lock); + mutex_lock(&slab_mutex); slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj); if (!slab_kset) { - up_write(&slub_lock); + mutex_unlock(&slab_mutex); printk(KERN_ERR "Cannot register slab subsystem.\n"); return -ENOSYS; } @@ -5389,7 +5385,7 @@ static int __init slab_sysfs_init(void) kfree(al); } - up_write(&slub_lock); + mutex_unlock(&slab_mutex); resiliency_test(); return 0; } @@ -5415,7 +5411,7 @@ static void *s_start(struct seq_file *m, loff_t *pos) { loff_t n = *pos; - down_read(&slub_lock); + mutex_lock(&slab_mutex); if (!n) print_slabinfo_header(m); @@ -5429,7 +5425,7 @@ static void *s_next(struct seq_file *m, void *p, loff_t *pos) static void s_stop(struct seq_file *m, void *p) { - up_read(&slub_lock); + mutex_unlock(&slab_mutex); } static int s_show(struct seq_file *m, void *p) -- cgit v1.1