forked from mirrors/linux
slab: introduce alien_cache
Currently, we use array_cache for alien_cache. Although they are mostly similar, there is one difference, that is, need for spinlock. We don't need spinlock for array_cache itself, but to use array_cache for alien_cache, array_cache structure should have spinlock. This is needless overhead, so removing it would be better. This patch prepare it by introducing alien_cache and using it. In the following patch, we remove spinlock in array_cache. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joonsoo Kim
Linus Torvalds
parent
1fe00d50a9
commit
c8522a3a58
2 changed files with 67 additions and 41 deletions
92
mm/slab.c
92
mm/slab.c
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@ -203,6 +203,11 @@ struct array_cache {
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*/
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};
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struct alien_cache {
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spinlock_t lock;
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struct array_cache ac;
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};
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#define SLAB_OBJ_PFMEMALLOC 1
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static inline bool is_obj_pfmemalloc(void *objp)
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{
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@ -491,7 +496,7 @@ static void slab_set_lock_classes(struct kmem_cache *cachep,
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struct lock_class_key *l3_key, struct lock_class_key *alc_key,
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struct kmem_cache_node *n)
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{
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struct array_cache **alc;
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struct alien_cache **alc;
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int r;
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lockdep_set_class(&n->list_lock, l3_key);
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@ -507,7 +512,7 @@ static void slab_set_lock_classes(struct kmem_cache *cachep,
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return;
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for_each_node(r) {
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if (alc[r])
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lockdep_set_class(&alc[r]->lock, alc_key);
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lockdep_set_class(&(alc[r]->ac.lock), alc_key);
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}
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}
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@ -965,12 +970,13 @@ static int transfer_objects(struct array_cache *to,
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#define drain_alien_cache(cachep, alien) do { } while (0)
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#define reap_alien(cachep, n) do { } while (0)
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static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
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static inline struct alien_cache **alloc_alien_cache(int node,
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int limit, gfp_t gfp)
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{
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return (struct array_cache **)BAD_ALIEN_MAGIC;
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return (struct alien_cache **)BAD_ALIEN_MAGIC;
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}
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static inline void free_alien_cache(struct array_cache **ac_ptr)
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static inline void free_alien_cache(struct alien_cache **ac_ptr)
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{
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}
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@ -996,40 +1002,52 @@ static inline void *____cache_alloc_node(struct kmem_cache *cachep,
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static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
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static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
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static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
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static struct alien_cache *__alloc_alien_cache(int node, int entries,
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int batch, gfp_t gfp)
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{
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struct array_cache **ac_ptr;
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int memsize = sizeof(void *) * entries + sizeof(struct alien_cache);
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struct alien_cache *alc = NULL;
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alc = kmalloc_node(memsize, gfp, node);
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init_arraycache(&alc->ac, entries, batch);
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return alc;
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}
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static struct alien_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
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{
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struct alien_cache **alc_ptr;
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int memsize = sizeof(void *) * nr_node_ids;
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int i;
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if (limit > 1)
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limit = 12;
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ac_ptr = kzalloc_node(memsize, gfp, node);
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if (ac_ptr) {
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alc_ptr = kzalloc_node(memsize, gfp, node);
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if (!alc_ptr)
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return NULL;
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for_each_node(i) {
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if (i == node || !node_online(i))
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continue;
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ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp);
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if (!ac_ptr[i]) {
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alc_ptr[i] = __alloc_alien_cache(node, limit, 0xbaadf00d, gfp);
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if (!alc_ptr[i]) {
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for (i--; i >= 0; i--)
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kfree(ac_ptr[i]);
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kfree(ac_ptr);
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kfree(alc_ptr[i]);
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kfree(alc_ptr);
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return NULL;
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}
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}
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}
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return ac_ptr;
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return alc_ptr;
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}
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static void free_alien_cache(struct array_cache **ac_ptr)
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static void free_alien_cache(struct alien_cache **alc_ptr)
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{
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int i;
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if (!ac_ptr)
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if (!alc_ptr)
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return;
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for_each_node(i)
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kfree(ac_ptr[i]);
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kfree(ac_ptr);
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kfree(alc_ptr[i]);
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kfree(alc_ptr);
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}
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static void __drain_alien_cache(struct kmem_cache *cachep,
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@ -1063,25 +1081,31 @@ static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n)
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int node = __this_cpu_read(slab_reap_node);
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if (n->alien) {
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struct array_cache *ac = n->alien[node];
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struct alien_cache *alc = n->alien[node];
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struct array_cache *ac;
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if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
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if (alc) {
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ac = &alc->ac;
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if (ac->avail && spin_trylock_irq(&ac->lock)) {
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__drain_alien_cache(cachep, ac, node);
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spin_unlock_irq(&ac->lock);
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}
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}
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}
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}
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static void drain_alien_cache(struct kmem_cache *cachep,
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struct array_cache **alien)
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struct alien_cache **alien)
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{
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int i = 0;
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struct alien_cache *alc;
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struct array_cache *ac;
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unsigned long flags;
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for_each_online_node(i) {
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ac = alien[i];
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if (ac) {
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alc = alien[i];
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if (alc) {
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ac = &alc->ac;
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spin_lock_irqsave(&ac->lock, flags);
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__drain_alien_cache(cachep, ac, i);
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spin_unlock_irqrestore(&ac->lock, flags);
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@ -1093,7 +1117,8 @@ static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
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{
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int nodeid = page_to_nid(virt_to_page(objp));
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struct kmem_cache_node *n;
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struct array_cache *alien = NULL;
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struct alien_cache *alien = NULL;
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struct array_cache *ac;
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int node;
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LIST_HEAD(list);
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@ -1110,13 +1135,14 @@ static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
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STATS_INC_NODEFREES(cachep);
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if (n->alien && n->alien[nodeid]) {
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alien = n->alien[nodeid];
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spin_lock(&alien->lock);
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if (unlikely(alien->avail == alien->limit)) {
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ac = &alien->ac;
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spin_lock(&ac->lock);
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if (unlikely(ac->avail == ac->limit)) {
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STATS_INC_ACOVERFLOW(cachep);
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__drain_alien_cache(cachep, alien, nodeid);
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__drain_alien_cache(cachep, ac, nodeid);
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}
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ac_put_obj(cachep, alien, objp);
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spin_unlock(&alien->lock);
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ac_put_obj(cachep, ac, objp);
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spin_unlock(&ac->lock);
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} else {
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n = get_node(cachep, nodeid);
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spin_lock(&n->list_lock);
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@ -1191,7 +1217,7 @@ static void cpuup_canceled(long cpu)
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list_for_each_entry(cachep, &slab_caches, list) {
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struct array_cache *nc;
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struct array_cache *shared;
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struct array_cache **alien;
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struct alien_cache **alien;
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LIST_HEAD(list);
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/* cpu is dead; no one can alloc from it. */
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@ -1272,7 +1298,7 @@ static int cpuup_prepare(long cpu)
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list_for_each_entry(cachep, &slab_caches, list) {
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struct array_cache *nc;
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struct array_cache *shared = NULL;
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struct array_cache **alien = NULL;
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struct alien_cache **alien = NULL;
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nc = alloc_arraycache(node, cachep->limit,
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cachep->batchcount, GFP_KERNEL);
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@ -3762,7 +3788,7 @@ static int alloc_kmem_cache_node(struct kmem_cache *cachep, gfp_t gfp)
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int node;
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struct kmem_cache_node *n;
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struct array_cache *new_shared;
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struct array_cache **new_alien = NULL;
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struct alien_cache **new_alien = NULL;
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for_each_online_node(node) {
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@ -276,7 +276,7 @@ struct kmem_cache_node {
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unsigned int free_limit;
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unsigned int colour_next; /* Per-node cache coloring */
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struct array_cache *shared; /* shared per node */
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struct array_cache **alien; /* on other nodes */
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struct alien_cache **alien; /* on other nodes */
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unsigned long next_reap; /* updated without locking */
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int free_touched; /* updated without locking */
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#endif
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