1 files changed, 108 insertions, 61 deletions

diff --git a/mm/slab.c b/mm/slab.c
index 71370256a7eb..9cc049a942c6 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -294,6 +294,7 @@ struct kmem_list3 {
         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 */
@@ -344,6 +345,7 @@ static void kmem_list3_init(struct kmem_list3 *parent)
         INIT_LIST_HEAD(&parent->slabs_free);
         parent->shared = NULL;
         parent->alien = NULL;
+        parent->colour_next = 0;
         spin_lock_init(&parent->list_lock);
         parent->free_objects = 0;
         parent->free_touched = 0;
@@ -390,7 +392,6 @@ struct kmem_cache {
 
         size_t colour;          /* cache colouring range */
         unsigned int colour_off;        /* colour offset */
-        unsigned int colour_next;       /* cache colouring */
         struct kmem_cache *slabp_cache;
         unsigned int slab_size;
         unsigned int dflags;    /* dynamic flags */
@@ -883,14 +884,14 @@ static void __drain_alien_cache(struct kmem_cache *cachep,
         }
 }
 
-static void drain_alien_cache(struct kmem_cache *cachep, struct kmem_list3 *l3)
+static void drain_alien_cache(struct kmem_cache *cachep, struct array_cache **alien)
 {
         int i = 0;
         struct array_cache *ac;
         unsigned long flags;
 
         for_each_online_node(i) {
-                ac = l3->alien[i];
+                ac = alien[i];
                 if (ac) {
                         spin_lock_irqsave(&ac->lock, flags);
                         __drain_alien_cache(cachep, ac, i);
@@ -900,8 +901,11 @@ static void drain_alien_cache(struct kmem_cache *cachep, struct kmem_list3 *l3)
 }
 #else
 #define alloc_alien_cache(node, limit) do { } while (0)
-#define free_alien_cache(ac_ptr) do { } while (0)
-#define drain_alien_cache(cachep, l3) do { } while (0)
+#define drain_alien_cache(cachep, alien) do { } while (0)
+
+static inline void free_alien_cache(struct array_cache **ac_ptr)
+{
+}
 #endif
 
 static int __devinit cpuup_callback(struct notifier_block *nfb,
@@ -935,6 +939,11 @@ static int __devinit cpuup_callback(struct notifier_block *nfb,
                                 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
                                     ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
 
+                                /*
+                                 * The l3s don't come and go as CPUs come and
+                                 * go.  cache_chain_mutex is sufficient
+                                 * protection here.
+                                 */
                                 cachep->nodelists[node] = l3;
                         }
 
@@ -949,26 +958,47 @@ static int __devinit cpuup_callback(struct notifier_block *nfb,
                    & array cache's */
                 list_for_each_entry(cachep, &cache_chain, next) {
                         struct array_cache *nc;
+                        struct array_cache *shared;
+                        struct array_cache **alien;
 
                         nc = alloc_arraycache(node, cachep->limit,
-                                              cachep->batchcount);
+                                                cachep->batchcount);
                         if (!nc)
                                 goto bad;
+                        shared = alloc_arraycache(node,
+                                        cachep->shared * cachep->batchcount,
+                                        0xbaadf00d);
+                        if (!shared)
+                                goto bad;
+#ifdef CONFIG_NUMA
+                        alien = alloc_alien_cache(node, cachep->limit);
+                        if (!alien)
+                                goto bad;
+#endif
                         cachep->array[cpu] = nc;
 
                         l3 = cachep->nodelists[node];
                         BUG_ON(!l3);
-                        if (!l3->shared) {
-                                if (!(nc = alloc_arraycache(node,
-                                                            cachep->shared *
-                                                            cachep->batchcount,
-                                                            0xbaadf00d)))
-                                        goto bad;
 
-                                /* we are serialised from CPU_DEAD or
-                                   CPU_UP_CANCELLED by the cpucontrol lock */
-                                l3->shared = nc;
+                        spin_lock_irq(&l3->list_lock);
+                        if (!l3->shared) {
+                                /*
+                                 * We are serialised from CPU_DEAD or
+                                 * CPU_UP_CANCELLED by the cpucontrol lock
+                                 */
+                                l3->shared = shared;
+                                shared = NULL;
+                        }
+#ifdef CONFIG_NUMA
+                        if (!l3->alien) {
+                                l3->alien = alien;
+                                alien = NULL;
                         }
+#endif
+                        spin_unlock_irq(&l3->list_lock);
+
+                        kfree(shared);
+                        free_alien_cache(alien);
                 }
                 mutex_unlock(&cache_chain_mutex);
                 break;
@@ -977,25 +1007,34 @@ static int __devinit cpuup_callback(struct notifier_block *nfb,
                 break;
 #ifdef CONFIG_HOTPLUG_CPU
         case CPU_DEAD:
+                /*
+                 * Even if all the cpus of a node are down, we don't free the
+                 * kmem_list3 of any cache. This to avoid a race between
+                 * cpu_down, and a kmalloc allocation from another cpu for
+                 * memory from the node of the cpu going down.  The list3
+                 * structure is usually allocated from kmem_cache_create() and
+                 * gets destroyed at kmem_cache_destroy().
+                 */
                 /* fall thru */
         case CPU_UP_CANCELED:
                 mutex_lock(&cache_chain_mutex);
 
                 list_for_each_entry(cachep, &cache_chain, next) {
                         struct array_cache *nc;
+                        struct array_cache *shared;
+                        struct array_cache **alien;
                         cpumask_t mask;
 
                         mask = node_to_cpumask(node);
-                        spin_lock_irq(&cachep->spinlock);
                         /* cpu is dead; no one can alloc from it. */
                         nc = cachep->array[cpu];
                         cachep->array[cpu] = NULL;
                         l3 = cachep->nodelists[node];
 
                         if (!l3)
-                                goto unlock_cache;
+                                goto free_array_cache;
 
-                        spin_lock(&l3->list_lock);
+                        spin_lock_irq(&l3->list_lock);
 
                         /* Free limit for this kmem_list3 */
                         l3->free_limit -= cachep->batchcount;
@@ -1003,34 +1042,44 @@ static int __devinit cpuup_callback(struct notifier_block *nfb,
                                 free_block(cachep, nc->entry, nc->avail, node);
 
                         if (!cpus_empty(mask)) {
-                                spin_unlock(&l3->list_lock);
-                                goto unlock_cache;
+                                spin_unlock_irq(&l3->list_lock);
+                                goto free_array_cache;
                         }
 
-                        if (l3->shared) {
+                        shared = l3->shared;
+                        if (shared) {
                                 free_block(cachep, l3->shared->entry,
                                            l3->shared->avail, node);
-                                kfree(l3->shared);
                                 l3->shared = NULL;
                         }
-                        if (l3->alien) {
-                                drain_alien_cache(cachep, l3);
-                                free_alien_cache(l3->alien);
-                                l3->alien = NULL;
-                        }
 
-                        /* free slabs belonging to this node */
-                        if (__node_shrink(cachep, node)) {
-                                cachep->nodelists[node] = NULL;
-                                spin_unlock(&l3->list_lock);
-                                kfree(l3);
-                        } else {
-                                spin_unlock(&l3->list_lock);
+                        alien = l3->alien;
+                        l3->alien = NULL;
+
+                        spin_unlock_irq(&l3->list_lock);
+
+                        kfree(shared);
+                        if (alien) {
+                                drain_alien_cache(cachep, alien);
+                                free_alien_cache(alien);
                         }
-                      unlock_cache:
-                        spin_unlock_irq(&cachep->spinlock);
+free_array_cache:
                         kfree(nc);
                 }
+                /*
+                 * In the previous loop, all the objects were freed to
+                 * the respective cache's slabs,  now we can go ahead and
+                 * shrink each nodelist to its limit.
+                 */
+                list_for_each_entry(cachep, &cache_chain, next) {
+                        l3 = cachep->nodelists[node];
+                        if (!l3)
+                                continue;
+                        spin_lock_irq(&l3->list_lock);
+                        /* free slabs belonging to this node */
+                        __node_shrink(cachep, node);
+                        spin_unlock_irq(&l3->list_lock);
+                }
                 mutex_unlock(&cache_chain_mutex);
                 break;
 #endif
@@ -1119,7 +1168,6 @@ void __init kmem_cache_init(void)
                 BUG();
 
         cache_cache.colour = left_over / cache_cache.colour_off;
-        cache_cache.colour_next = 0;
         cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) +
                                       sizeof(struct slab), cache_line_size());
 
@@ -2011,18 +2059,16 @@ static void drain_cpu_caches(struct kmem_cache *cachep)
 
         smp_call_function_all_cpus(do_drain, cachep);
         check_irq_on();
-        spin_lock_irq(&cachep->spinlock);
         for_each_online_node(node) {
                 l3 = cachep->nodelists[node];
                 if (l3) {
-                        spin_lock(&l3->list_lock);
+                        spin_lock_irq(&l3->list_lock);
                         drain_array_locked(cachep, l3->shared, 1, node);
-                        spin_unlock(&l3->list_lock);
+                        spin_unlock_irq(&l3->list_lock);
                         if (l3->alien)
-                                drain_alien_cache(cachep, l3);
+                                drain_alien_cache(cachep, l3->alien);
                 }
         }
-        spin_unlock_irq(&cachep->spinlock);
 }
 
 static int __node_shrink(struct kmem_cache *cachep, int node)
@@ -2324,20 +2370,20 @@ static int cache_grow(struct kmem_cache *cachep, gfp_t flags, int nodeid)
                  */
                 ctor_flags |= SLAB_CTOR_ATOMIC;
 
-        /* About to mess with non-constant members - lock. */
+        /* Take the l3 list lock to change the colour_next on this node */
         check_irq_off();
-        spin_lock(&cachep->spinlock);
+        l3 = cachep->nodelists[nodeid];
+        spin_lock(&l3->list_lock);
 
         /* Get colour for the slab, and cal the next value. */
-        offset = cachep->colour_next;
-        cachep->colour_next++;
-        if (cachep->colour_next >= cachep->colour)
-                cachep->colour_next = 0;
-        offset *= cachep->colour_off;
+        offset = l3->colour_next;
+        l3->colour_next++;
+        if (l3->colour_next >= cachep->colour)
+                l3->colour_next = 0;
+        spin_unlock(&l3->list_lock);
 
-        spin_unlock(&cachep->spinlock);
+        offset *= cachep->colour_off;
 
-        check_irq_off();
         if (local_flags & __GFP_WAIT)
                 local_irq_enable();
 
@@ -2367,7 +2413,6 @@ static int cache_grow(struct kmem_cache *cachep, gfp_t flags, int nodeid)
         if (local_flags & __GFP_WAIT)
                 local_irq_disable();
         check_irq_off();
-        l3 = cachep->nodelists[nodeid];
         spin_lock(&l3->list_lock);
 
         /* Make slab active. */
@@ -2725,6 +2770,7 @@ static void *__cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int node
         BUG_ON(!l3);
 
       retry:
+        check_irq_off();
         spin_lock(&l3->list_lock);
         entry = l3->slabs_partial.next;
         if (entry == &l3->slabs_partial) {
@@ -3304,11 +3350,11 @@ static int do_tune_cpucache(struct kmem_cache *cachep, int limit, int batchcount
         smp_call_function_all_cpus(do_ccupdate_local, (void *)&new);
 
         check_irq_on();
-        spin_lock_irq(&cachep->spinlock);
+        spin_lock(&cachep->spinlock);
         cachep->batchcount = batchcount;
         cachep->limit = limit;
         cachep->shared = shared;
-        spin_unlock_irq(&cachep->spinlock);
+        spin_unlock(&cachep->spinlock);
 
         for_each_online_cpu(i) {
                 struct array_cache *ccold = new.new[i];
@@ -3440,7 +3486,7 @@ static void cache_reap(void *unused)
 
                 l3 = searchp->nodelists[numa_node_id()];
                 if (l3->alien)
-                        drain_alien_cache(searchp, l3);
+                        drain_alien_cache(searchp, l3->alien);
                 spin_lock_irq(&l3->list_lock);
 
                 drain_array_locked(searchp, cpu_cache_get(searchp), 0,
@@ -3564,8 +3610,7 @@ static int s_show(struct seq_file *m, void *p)
         int node;
         struct kmem_list3 *l3;
 
-        check_irq_on();
-        spin_lock_irq(&cachep->spinlock);
+        spin_lock(&cachep->spinlock);
         active_objs = 0;
         num_slabs = 0;
         for_each_online_node(node) {
@@ -3573,7 +3618,8 @@ static int s_show(struct seq_file *m, void *p)
                 if (!l3)
                         continue;
 
-                spin_lock(&l3->list_lock);
+                check_irq_on();
+                spin_lock_irq(&l3->list_lock);
 
                 list_for_each(q, &l3->slabs_full) {
                         slabp = list_entry(q, struct slab, list);
@@ -3598,9 +3644,10 @@ static int s_show(struct seq_file *m, void *p)
                         num_slabs++;
                 }
                 free_objects += l3->free_objects;
-                shared_avail += l3->shared->avail;
+                if (l3->shared)
+                        shared_avail += l3->shared->avail;
 
-                spin_unlock(&l3->list_lock);
+                spin_unlock_irq(&l3->list_lock);
         }
         num_slabs += active_slabs;
         num_objs = num_slabs * cachep->num;
@@ -3644,7 +3691,7 @@ static int s_show(struct seq_file *m, void *p)
         }
 #endif
         seq_putc(m, '\n');
-        spin_unlock_irq(&cachep->spinlock);
+        spin_unlock(&cachep->spinlock);
         return 0;
 }