From: Christoph Lameter Date: Fri, 6 Jul 2012 20:25:12 +0000 (-0500) Subject: mm, sl[aou]b: Use a common mutex definition X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=18004c5d4084d965aa1396392706b8688306427a;hp=97d06609158e61f6bdf538c4a6788e2de492236f;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git 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 --- diff --git a/mm/slab.c b/mm/slab.c index 59a466b85b0f..fd7dac67c26e 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -68,7 +68,7 @@ * Further notes from the original documentation: * * 11 April '97. Started multi-threading - markhe - * The global cache-chain is protected by the mutex 'cache_chain_mutex'. + * The global cache-chain is protected by the mutex 'slab_mutex'. * The sem is only needed when accessing/extending the cache-chain, which * can never happen inside an interrupt (kmem_cache_create(), * kmem_cache_shrink() and kmem_cache_reap()). @@ -671,12 +671,6 @@ static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep) } #endif -/* - * Guard access to the cache-chain. - */ -static DEFINE_MUTEX(cache_chain_mutex); -static struct list_head cache_chain; - static DEFINE_PER_CPU(struct delayed_work, slab_reap_work); static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep) @@ -1100,7 +1094,7 @@ static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) * When hotplugging memory or a cpu, existing nodelists are not replaced if * already in use. * - * Must hold cache_chain_mutex. + * Must hold slab_mutex. */ static int init_cache_nodelists_node(int node) { @@ -1108,7 +1102,7 @@ static int init_cache_nodelists_node(int node) struct kmem_list3 *l3; const int memsize = sizeof(struct kmem_list3); - list_for_each_entry(cachep, &cache_chain, list) { + list_for_each_entry(cachep, &slab_caches, list) { /* * Set up the size64 kmemlist for cpu before we can * begin anything. Make sure some other cpu on this @@ -1124,7 +1118,7 @@ static int init_cache_nodelists_node(int node) /* * The l3s don't come and go as CPUs come and - * go. cache_chain_mutex is sufficient + * go. slab_mutex is sufficient * protection here. */ cachep->nodelists[node] = l3; @@ -1146,7 +1140,7 @@ static void __cpuinit cpuup_canceled(long cpu) int node = cpu_to_mem(cpu); const struct cpumask *mask = cpumask_of_node(node); - list_for_each_entry(cachep, &cache_chain, list) { + list_for_each_entry(cachep, &slab_caches, list) { struct array_cache *nc; struct array_cache *shared; struct array_cache **alien; @@ -1196,7 +1190,7 @@ free_array_cache: * the respective cache's slabs, now we can go ahead and * shrink each nodelist to its limit. */ - list_for_each_entry(cachep, &cache_chain, list) { + list_for_each_entry(cachep, &slab_caches, list) { l3 = cachep->nodelists[node]; if (!l3) continue; @@ -1225,7 +1219,7 @@ static int __cpuinit cpuup_prepare(long cpu) * Now we can go ahead with allocating the shared arrays and * array caches */ - list_for_each_entry(cachep, &cache_chain, list) { + list_for_each_entry(cachep, &slab_caches, list) { struct array_cache *nc; struct array_cache *shared = NULL; struct array_cache **alien = NULL; @@ -1293,9 +1287,9 @@ static int __cpuinit cpuup_callback(struct notifier_block *nfb, switch (action) { case CPU_UP_PREPARE: case CPU_UP_PREPARE_FROZEN: - mutex_lock(&cache_chain_mutex); + mutex_lock(&slab_mutex); err = cpuup_prepare(cpu); - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); break; case CPU_ONLINE: case CPU_ONLINE_FROZEN: @@ -1305,7 +1299,7 @@ static int __cpuinit cpuup_callback(struct notifier_block *nfb, case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: /* - * Shutdown cache reaper. Note that the cache_chain_mutex is + * Shutdown cache reaper. Note that the slab_mutex is * held so that if cache_reap() is invoked it cannot do * anything expensive but will only modify reap_work * and reschedule the timer. @@ -1332,9 +1326,9 @@ static int __cpuinit cpuup_callback(struct notifier_block *nfb, #endif case CPU_UP_CANCELED: case CPU_UP_CANCELED_FROZEN: - mutex_lock(&cache_chain_mutex); + mutex_lock(&slab_mutex); cpuup_canceled(cpu); - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); break; } return notifier_from_errno(err); @@ -1350,14 +1344,14 @@ static struct notifier_block __cpuinitdata cpucache_notifier = { * Returns -EBUSY if all objects cannot be drained so that the node is not * removed. * - * Must hold cache_chain_mutex. + * Must hold slab_mutex. */ static int __meminit drain_cache_nodelists_node(int node) { struct kmem_cache *cachep; int ret = 0; - list_for_each_entry(cachep, &cache_chain, list) { + list_for_each_entry(cachep, &slab_caches, list) { struct kmem_list3 *l3; l3 = cachep->nodelists[node]; @@ -1388,14 +1382,14 @@ static int __meminit slab_memory_callback(struct notifier_block *self, switch (action) { case MEM_GOING_ONLINE: - mutex_lock(&cache_chain_mutex); + mutex_lock(&slab_mutex); ret = init_cache_nodelists_node(nid); - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); break; case MEM_GOING_OFFLINE: - mutex_lock(&cache_chain_mutex); + mutex_lock(&slab_mutex); ret = drain_cache_nodelists_node(nid); - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); break; case MEM_ONLINE: case MEM_OFFLINE: @@ -1499,8 +1493,8 @@ void __init kmem_cache_init(void) node = numa_mem_id(); /* 1) create the cache_cache */ - INIT_LIST_HEAD(&cache_chain); - list_add(&cache_cache.list, &cache_chain); + INIT_LIST_HEAD(&slab_caches); + list_add(&cache_cache.list, &slab_caches); cache_cache.colour_off = cache_line_size(); cache_cache.array[smp_processor_id()] = &initarray_cache.cache; cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE + node]; @@ -1642,11 +1636,11 @@ void __init kmem_cache_init_late(void) init_lock_keys(); /* 6) resize the head arrays to their final sizes */ - mutex_lock(&cache_chain_mutex); - list_for_each_entry(cachep, &cache_chain, list) + mutex_lock(&slab_mutex); + list_for_each_entry(cachep, &slab_caches, list) if (enable_cpucache(cachep, GFP_NOWAIT)) BUG(); - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); /* Done! */ slab_state = FULL; @@ -2253,10 +2247,10 @@ __kmem_cache_create (const char *name, size_t size, size_t align, */ if (slab_is_available()) { get_online_cpus(); - mutex_lock(&cache_chain_mutex); + mutex_lock(&slab_mutex); } - list_for_each_entry(pc, &cache_chain, list) { + list_for_each_entry(pc, &slab_caches, list) { char tmp; int res; @@ -2500,10 +2494,10 @@ __kmem_cache_create (const char *name, size_t size, size_t align, } /* cache setup completed, link it into the list */ - list_add(&cachep->list, &cache_chain); + list_add(&cachep->list, &slab_caches); oops: if (slab_is_available()) { - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); put_online_cpus(); } return cachep; @@ -2622,7 +2616,7 @@ out: return nr_freed; } -/* Called with cache_chain_mutex held to protect against cpu hotplug */ +/* Called with slab_mutex held to protect against cpu hotplug */ static int __cache_shrink(struct kmem_cache *cachep) { int ret = 0, i = 0; @@ -2657,9 +2651,9 @@ int kmem_cache_shrink(struct kmem_cache *cachep) BUG_ON(!cachep || in_interrupt()); get_online_cpus(); - mutex_lock(&cache_chain_mutex); + mutex_lock(&slab_mutex); ret = __cache_shrink(cachep); - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); put_online_cpus(); return ret; } @@ -2687,15 +2681,15 @@ void kmem_cache_destroy(struct kmem_cache *cachep) /* Find the cache in the chain of caches. */ get_online_cpus(); - mutex_lock(&cache_chain_mutex); + mutex_lock(&slab_mutex); /* * the chain is never empty, cache_cache is never destroyed */ list_del(&cachep->list); if (__cache_shrink(cachep)) { slab_error(cachep, "Can't free all objects"); - list_add(&cachep->list, &cache_chain); - mutex_unlock(&cache_chain_mutex); + list_add(&cachep->list, &slab_caches); + mutex_unlock(&slab_mutex); put_online_cpus(); return; } @@ -2704,7 +2698,7 @@ void kmem_cache_destroy(struct kmem_cache *cachep) rcu_barrier(); __kmem_cache_destroy(cachep); - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); put_online_cpus(); } EXPORT_SYMBOL(kmem_cache_destroy); @@ -4017,7 +4011,7 @@ static void do_ccupdate_local(void *info) new->new[smp_processor_id()] = old; } -/* Always called with the cache_chain_mutex held */ +/* Always called with the slab_mutex held */ static int do_tune_cpucache(struct kmem_cache *cachep, int limit, int batchcount, int shared, gfp_t gfp) { @@ -4061,7 +4055,7 @@ static int do_tune_cpucache(struct kmem_cache *cachep, int limit, return alloc_kmemlist(cachep, gfp); } -/* Called with cache_chain_mutex held always */ +/* Called with slab_mutex held always */ static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp) { int err; @@ -4163,11 +4157,11 @@ static void cache_reap(struct work_struct *w) int node = numa_mem_id(); struct delayed_work *work = to_delayed_work(w); - if (!mutex_trylock(&cache_chain_mutex)) + if (!mutex_trylock(&slab_mutex)) /* Give up. Setup the next iteration. */ goto out; - list_for_each_entry(searchp, &cache_chain, list) { + list_for_each_entry(searchp, &slab_caches, list) { check_irq_on(); /* @@ -4205,7 +4199,7 @@ next: cond_resched(); } check_irq_on(); - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); next_reap_node(); out: /* Set up the next iteration */ @@ -4241,21 +4235,21 @@ static void *s_start(struct seq_file *m, loff_t *pos) { loff_t n = *pos; - mutex_lock(&cache_chain_mutex); + mutex_lock(&slab_mutex); if (!n) print_slabinfo_header(m); - return seq_list_start(&cache_chain, *pos); + return seq_list_start(&slab_caches, *pos); } static void *s_next(struct seq_file *m, void *p, loff_t *pos) { - return seq_list_next(p, &cache_chain, pos); + return seq_list_next(p, &slab_caches, pos); } static void s_stop(struct seq_file *m, void *p) { - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); } static int s_show(struct seq_file *m, void *p) @@ -4406,9 +4400,9 @@ static ssize_t slabinfo_write(struct file *file, const char __user *buffer, return -EINVAL; /* Find the cache in the chain of caches. */ - mutex_lock(&cache_chain_mutex); + mutex_lock(&slab_mutex); res = -EINVAL; - list_for_each_entry(cachep, &cache_chain, list) { + list_for_each_entry(cachep, &slab_caches, list) { if (!strcmp(cachep->name, kbuf)) { if (limit < 1 || batchcount < 1 || batchcount > limit || shared < 0) { @@ -4421,7 +4415,7 @@ static ssize_t slabinfo_write(struct file *file, const char __user *buffer, break; } } - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); if (res >= 0) res = count; return res; @@ -4444,8 +4438,8 @@ static const struct file_operations proc_slabinfo_operations = { static void *leaks_start(struct seq_file *m, loff_t *pos) { - mutex_lock(&cache_chain_mutex); - return seq_list_start(&cache_chain, *pos); + mutex_lock(&slab_mutex); + return seq_list_start(&slab_caches, *pos); } static inline int add_caller(unsigned long *n, unsigned long v) @@ -4544,17 +4538,17 @@ static int leaks_show(struct seq_file *m, void *p) name = cachep->name; if (n[0] == n[1]) { /* Increase the buffer size */ - mutex_unlock(&cache_chain_mutex); + mutex_unlock(&slab_mutex); m->private = kzalloc(n[0] * 4 * sizeof(unsigned long), GFP_KERNEL); if (!m->private) { /* Too bad, we are really out */ m->private = n; - mutex_lock(&cache_chain_mutex); + mutex_lock(&slab_mutex); return -ENOMEM; } *(unsigned long *)m->private = n[0] * 2; kfree(n); - mutex_lock(&cache_chain_mutex); + mutex_lock(&slab_mutex); /* Now make sure this entry will be retried */ m->count = m->size; return 0; diff --git a/mm/slab.h b/mm/slab.h index f9a9815cdc82..db7848caaa25 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -23,6 +23,10 @@ enum slab_state { extern enum slab_state slab_state; +/* The slab cache mutex protects the management structures during changes */ +extern struct mutex slab_mutex; +extern struct list_head slab_caches; + struct kmem_cache *__kmem_cache_create(const char *name, size_t size, size_t align, unsigned long flags, void (*ctor)(void *)); diff --git a/mm/slab_common.c b/mm/slab_common.c index ca1aaf69a1f5..50e1ff10bff9 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -19,6 +19,8 @@ #include "slab.h" enum slab_state slab_state; +LIST_HEAD(slab_caches); +DEFINE_MUTEX(slab_mutex); /* * kmem_cache_create - Create a cache. diff --git a/mm/slub.c b/mm/slub.c index 4c385164d9f7..8c4fd37541d7 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)