Re: [PATCH 2/4] slub: Use new node functions

[Christoph Lameter <cl@gentwo.org>]

On Mon, 2 Jun 2014, Joonsoo Kim wrote:

> I think that we can use for_each_kmem_cache_node() instead of
> using for_each_node_state(node, N_NORMAL_MEMORY). Just one
> exception is init_kmem_cache_nodes() which is responsible
> for setting kmem_cache_node correctly.

Yup.

> Is there any reason not to use it for for_each_node_state()?

There are two cases in which is doesnt work. free_kmem_cache_nodes() and
init_kmem_cache_nodes() as you noted before. And there is a case in the
statistics subsystem that needs to be handled a bit differently.

Here is a patch doing the additional modifications:




Subject: slub: Replace for_each_node_state with for_each_kmem_cache_node

More uses for the new function.

Signed-off-by: Christoph Lameter <cl@linux.com>

Index: linux/mm/slub.c
===================================================================
--- linux.orig/mm/slub.c	2014-05-30 13:23:24.863105538 -0500
+++ linux/mm/slub.c	2014-06-02 10:39:50.218883865 -0500
@@ -3210,11 +3210,11 @@ static void free_partial(struct kmem_cac
 static inline int kmem_cache_close(struct kmem_cache *s)
 {
 	int node;
+	struct kmem_cache_node *n;

 	flush_all(s);
 	/* Attempt to free all objects */
-	for_each_node_state(node, N_NORMAL_MEMORY) {
-		struct kmem_cache_node *n = get_node(s, node);
+	for_each_kmem_cache_node(s, node, n) {

 		free_partial(s, n);
 		if (n->nr_partial || slabs_node(s, node))
@@ -3400,11 +3400,7 @@ int kmem_cache_shrink(struct kmem_cache
 		return -ENOMEM;

 	flush_all(s);
-	for_each_node_state(node, N_NORMAL_MEMORY) {
-		n = get_node(s, node);
-
-		if (!n->nr_partial)
-			continue;
+	for_each_kmem_cache_node(s, node, n) {

 		for (i = 0; i < objects; i++)
 			INIT_LIST_HEAD(slabs_by_inuse + i);
@@ -3575,6 +3571,7 @@ static struct kmem_cache * __init bootst
 {
 	int node;
 	struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
+	struct kmem_cache_node *n;

 	memcpy(s, static_cache, kmem_cache->object_size);

@@ -3584,19 +3581,16 @@ static struct kmem_cache * __init bootst
 	 * IPIs around.
 	 */
 	__flush_cpu_slab(s, smp_processor_id());
-	for_each_node_state(node, N_NORMAL_MEMORY) {
-		struct kmem_cache_node *n = get_node(s, node);
+	for_each_kmem_cache_node(s, node, n) {
 		struct page *p;

-		if (n) {
-			list_for_each_entry(p, &n->partial, lru)
-				p->slab_cache = s;
+		list_for_each_entry(p, &n->partial, lru)
+			p->slab_cache = s;

 #ifdef CONFIG_SLUB_DEBUG
-			list_for_each_entry(p, &n->full, lru)
-				p->slab_cache = s;
+		list_for_each_entry(p, &n->full, lru)
+			p->slab_cache = s;
 #endif
-		}
 	}
 	list_add(&s->list, &slab_caches);
 	return s;
@@ -3952,16 +3946,14 @@ static long validate_slab_cache(struct k
 	unsigned long count = 0;
 	unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
 				sizeof(unsigned long), GFP_KERNEL);
+	struct kmem_cache_node *n;

 	if (!map)
 		return -ENOMEM;

 	flush_all(s);
-	for_each_node_state(node, N_NORMAL_MEMORY) {
-		struct kmem_cache_node *n = get_node(s, node);
-
+	for_each_kmem_cache_node(s, node, n)
 		count += validate_slab_node(s, n, map);
-	}
 	kfree(map);
 	return count;
 }
@@ -4115,6 +4107,7 @@ static int list_locations(struct kmem_ca
 	int node;
 	unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
 				     sizeof(unsigned long), GFP_KERNEL);
+	struct kmem_cache_node *n;

 	if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
 				     GFP_TEMPORARY)) {
@@ -4124,8 +4117,7 @@ static int list_locations(struct kmem_ca
 	/* Push back cpu slabs */
 	flush_all(s);

-	for_each_node_state(node, N_NORMAL_MEMORY) {
-		struct kmem_cache_node *n = get_node(s, node);
+	for_each_kmem_cache_node(s, node, n) {
 		unsigned long flags;
 		struct page *page;

@@ -4327,8 +4319,9 @@ static ssize_t show_slab_objects(struct
 	lock_memory_hotplug();
 #ifdef CONFIG_SLUB_DEBUG
 	if (flags & SO_ALL) {
-		for_each_node_state(node, N_NORMAL_MEMORY) {
-			struct kmem_cache_node *n = get_node(s, node);
+		struct kmem_cache_node *n;
+
+		for_each_kmem_cache_node(s, node, n) {

 			if (flags & SO_TOTAL)
 				x = atomic_long_read(&n->total_objects);
@@ -4344,8 +4337,9 @@ static ssize_t show_slab_objects(struct
 	} else
 #endif
 	if (flags & SO_PARTIAL) {
-		for_each_node_state(node, N_NORMAL_MEMORY) {
-			struct kmem_cache_node *n = get_node(s, node);
+		struct kmem_cache_node *n;
+
+		for_each_kmem_cache_node(s, node, n) {

 			if (flags & SO_TOTAL)
 				x = count_partial(n, count_total);
@@ -4359,7 +4353,7 @@ static ssize_t show_slab_objects(struct
 	}
 	x = sprintf(buf, "%lu", total);
 #ifdef CONFIG_NUMA
-	for_each_node_state(node, N_NORMAL_MEMORY)
+	for(node = 0; node < nr_node_ids; node++)
 		if (nodes[node])
 			x += sprintf(buf + x, " N%d=%lu",
 					node, nodes[node]);

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