From df30315681197e7d080af69ee7e4bf2961f8374e Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Tue, 13 Oct 2009 10:05:40 -0500
Subject: [PATCH] slab: Cover the numa aliens with the per cpu locked changes

commit d99f9884403747e8668442b9ce61b28a9d6bcd4a in tip.

The numa aliens tear down is not covered by the per cpu locked changes
which we did to slab. Fix that.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/mm/slab.c b/mm/slab.c
index 4641c47..985c67b 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -164,6 +164,9 @@ static void slab_irq_disable_GFP_WAIT(gfp_t flags, int *cpu)
 		local_irq_disable();
 }
 
+#define slab_spin_trylock_irq(lock, cpu) \
+	({ int __l = spin_trylock_irq(lock); if (__l) (cpu) = smp_processor_id(); __l; })
+
 # define slab_spin_lock_irq(lock, cpu) \
 	do { spin_lock_irq(lock); (cpu) = smp_processor_id(); } while (0)
 # define slab_spin_unlock_irq(lock, cpu) spin_unlock_irq(lock)
@@ -241,10 +244,26 @@ static void slab_irq_disable_GFP_WAIT(gfp_t flags, int *cpu)
 	slab_irq_disable(*cpu);
 }
 
+static inline int _slab_spin_trylock_irq(spinlock_t *lock, int *cpu)
+{
+	int locked;
+
+	slab_irq_disable(*cpu);
+	locked = spin_trylock(lock);
+	if (!locked)
+		slab_irq_enable(*cpu);
+
+	return locked;
+}
+
+# define slab_spin_trylock_irq(lock, cpu) \
+	_slab_spin_trylock_irq((lock), &(cpu))
+
 # define slab_spin_lock_irq(lock, cpu) \
 		do { slab_irq_disable(cpu); spin_lock(lock); } while (0)
 # define slab_spin_unlock_irq(lock, cpu) \
 		do { spin_unlock(lock); slab_irq_enable(cpu); } while (0)
+
 # define slab_spin_lock_irqsave(lock, flags, cpu) \
 	do { slab_irq_disable(cpu); spin_lock_irqsave(lock, flags); } while (0)
 # define slab_spin_unlock_irqrestore(lock, flags, cpu) \
@@ -1075,7 +1094,7 @@ static int transfer_objects(struct array_cache *to,
 #ifndef CONFIG_NUMA
 
 #define drain_alien_cache(cachep, alien) do { } while (0)
-#define reap_alien(cachep, l3, this_cpu) 0
+#define reap_alien(cachep, l3) 0
 
 static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
 {
@@ -1172,17 +1191,18 @@ static void __drain_alien_cache(struct kmem_cache *cachep,
 /*
  * Called from cache_reap() to regularly drain alien caches round robin.
  */
-static int
-reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3, int *this_cpu)
+static int reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3)
 {
-	int node = per_cpu(slab_reap_node, *this_cpu);
+	int node = __get_cpu_var(slab_reap_node);
+	int this_cpu;
 
 	if (l3->alien) {
 		struct array_cache *ac = l3->alien[node];
 
-		if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
-			__drain_alien_cache(cachep, ac, node, this_cpu);
-			spin_unlock_irq(&ac->lock);
+		if (ac && ac->avail &&
+		    slab_spin_trylock_irq(&ac->lock, this_cpu)) {
+			__drain_alien_cache(cachep, ac, node, &this_cpu);
+			slab_spin_unlock_irq(&ac->lock, this_cpu);
 			return 1;
 		}
 	}
@@ -4293,7 +4313,7 @@ int drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
  */
 static void cache_reap(struct work_struct *w)
 {
-	int this_cpu = raw_smp_processor_id(), node = cpu_to_node(this_cpu);
+	int this_cpu = smp_processor_id(), node = cpu_to_node(this_cpu);
 	struct kmem_cache *searchp;
 	struct kmem_list3 *l3;
 	struct delayed_work *work = to_delayed_work(w);
@@ -4313,7 +4333,7 @@ static void cache_reap(struct work_struct *w)
 		 */
 		l3 = searchp->nodelists[node];
 
-		work_done += reap_alien(searchp, l3, &this_cpu);
+		work_done += reap_alien(searchp, l3);
 
 		node = cpu_to_node(this_cpu);
 
-- 
1.7.1.1