[PATCH 01/10] mempool: Add mempool_init()/mempool_exit()

Kent Overstreet
2018-05-09T01:33:49Z

Allows mempools to be embedded in other structs, getting rid of a
pointer indirection from allocation fastpaths.

mempool_exit() is safe to call on an uninitialized but zeroed mempool.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
---
include/linux/mempool.h | 34 +++++++++++++
mm/mempool.c | 108 ++++++++++++++++++++++++++++++----------
2 files changed, 115 insertions(+), 27 deletions(-)

diff --git a/include/linux/mempool.h b/include/linux/mempool.h
index b51f5c430c..0c964ac107 100644
--- a/include/linux/mempool.h
+++ b/include/linux/mempool.h
@@ -25,6 +25,18 @@ typedef struct mempool_s {
wait_queue_head_t wait;
} mempool_t;

+static inline bool mempool_initialized(mempool_t *pool)
+{
+ return pool->elements != NULL;
+}
+
+void mempool_exit(mempool_t *pool);
+int mempool_init_node(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
+ mempool_free_t *free_fn, void *pool_data,
+ gfp_t gfp_mask, int node_id);
+int mempool_init(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
+ mempool_free_t *free_fn, void *pool_data);
+
extern mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
mempool_free_t *free_fn, void *pool_data);
extern mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
@@ -43,6 +55,14 @@ extern void mempool_free(void *element, mempool_t *pool);
*/
void *mempool_alloc_slab(gfp_t gfp_mask, void *pool_data);
void mempool_free_slab(void *element, void *pool_data);
+
+static inline int
+mempool_init_slab_pool(mempool_t *pool, int min_nr, struct kmem_cache *kc)
+{
+ return mempool_init(pool, min_nr, mempool_alloc_slab,
+ mempool_free_slab, (void *) kc);
+}
+
static inline mempool_t *
mempool_create_slab_pool(int min_nr, struct kmem_cache *kc)
{
@@ -56,6 +76,13 @@ mempool_create_slab_pool(int min_nr, struct kmem_cache *kc)
*/
void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data);
void mempool_kfree(void *element, void *pool_data);
+
+static inline int mempool_init_kmalloc_pool(mempool_t *pool, int min_nr, size_t size)
+{
+ return mempool_init(pool, min_nr, mempool_kmalloc,
+ mempool_kfree, (void *) size);
+}
+
static inline mempool_t *mempool_create_kmalloc_pool(int min_nr, size_t size)
{
return mempool_create(min_nr, mempool_kmalloc, mempool_kfree,
@@ -68,6 +95,13 @@ static inline mempool_t *mempool_create_kmalloc_pool(int min_nr, size_t size)
*/
void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data);
void mempool_free_pages(void *element, void *pool_data);
+
+static inline int mempool_init_page_pool(mempool_t *pool, int min_nr, int order)
+{
+ return mempool_init(pool, min_nr, mempool_alloc_pages,
+ mempool_free_pages, (void *)(long)order);
+}
+
static inline mempool_t *mempool_create_page_pool(int min_nr, int order)
{
return mempool_create(min_nr, mempool_alloc_pages, mempool_free_pages,
diff --git a/mm/mempool.c b/mm/mempool.c
index 5c9dce3471..df90ace400 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -137,6 +137,28 @@ static void *remove_element(mempool_t *pool, gfp_t flags)
return element;
}

+/**
+ * mempool_destroy - exit a mempool initialized with mempool_init()
+ * @pool: pointer to the memory pool which was initialized with
+ * mempool_init().
+ *
+ * Free all reserved elements in @pool and @pool itself. This function
+ * only sleeps if the free_fn() function sleeps.
+ *
+ * May be called on a zeroed but uninitialized mempool (i.e. allocated with
+ * kzalloc()).
+ */
+void mempool_exit(mempool_t *pool)
+{
+ while (pool->curr_nr) {
+ void *element = remove_element(pool, GFP_KERNEL);
+ pool->free(element, pool->pool_data);
+ }
+ kfree(pool->elements);
+ pool->elements = NULL;
+}
+EXPORT_SYMBOL(mempool_exit);
+
/**
* mempool_destroy - deallocate a memory pool
* @pool: pointer to the memory pool which was allocated via
@@ -150,15 +172,65 @@ void mempool_destroy(mempool_t *pool)
if (unlikely(!pool))
return;

- while (pool->curr_nr) {
- void *element = remove_element(pool, GFP_KERNEL);
- pool->free(element, pool->pool_data);
- }
- kfree(pool->elements);
+ mempool_exit(pool);
kfree(pool);
}
EXPORT_SYMBOL(mempool_destroy);

+int mempool_init_node(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
+ mempool_free_t *free_fn, void *pool_data,
+ gfp_t gfp_mask, int node_id)
+{
+ spin_lock_init(&pool->lock);
+ pool->min_nr = min_nr;
+ pool->pool_data = pool_data;
+ pool->alloc = alloc_fn;
+ pool->free = free_fn;
+ init_waitqueue_head(&pool->wait);
+
+ pool->elements = kmalloc_array_node(min_nr, sizeof(void *),
+ gfp_mask, node_id);
+ if (!pool->elements)
+ return -ENOMEM;
+
+ /*
+ * First pre-allocate the guaranteed number of buffers.
+ */
+ while (pool->curr_nr < pool->min_nr) {
+ void *element;
+
+ element = pool->alloc(gfp_mask, pool->pool_data);
+ if (unlikely(!element)) {
+ mempool_exit(pool);
+ return -ENOMEM;
+ }
+ add_element(pool, element);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(mempool_init_node);
+
+/**
+ * mempool_init - initialize a memory pool
+ * @min_nr: the minimum number of elements guaranteed to be
+ * allocated for this pool.
+ * @alloc_fn: user-defined element-allocation function.
+ * @free_fn: user-defined element-freeing function.
+ * @pool_data: optional private data available to the user-defined functions.
+ *
+ * Like mempool_create(), but initializes the pool in (i.e. embedded in another
+ * structure).
+ */
+int mempool_init(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
+ mempool_free_t *free_fn, void *pool_data)
+{
+ return mempool_init_node(pool, min_nr, alloc_fn, free_fn,
+ pool_data, GFP_KERNEL, NUMA_NO_NODE);
+
+}
+EXPORT_SYMBOL(mempool_init);
+
/**
* mempool_create - create a memory pool
* @min_nr: the minimum number of elements guaranteed to be
@@ -186,35 +258,17 @@ mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
gfp_t gfp_mask, int node_id)
{
mempool_t *pool;
+
pool = kzalloc_node(sizeof(*pool), gfp_mask, node_id);
if (!pool)
return NULL;
- pool->elements = kmalloc_array_node(min_nr, sizeof(void *),
- gfp_mask, node_id);
- if (!pool->elements) {
+
+ if (mempool_init_node(pool, min_nr, alloc_fn, free_fn, pool_data,
+ gfp_mask, node_id)) {
kfree(pool);
return NULL;
}
- spin_lock_init(&pool->lock);
- pool->min_nr = min_nr;
- pool->pool_data = pool_data;
- init_waitqueue_head(&pool->wait);
- pool->alloc = alloc_fn;
- pool->free = free_fn;

- /*
- * First pre-allocate the guaranteed number of buffers.
- */
- while (pool->curr_nr < pool->min_nr) {
- void *element;
-
- element = pool->alloc(gfp_mask, pool->pool_data);
- if (unlikely(!element)) {
- mempool_destroy(pool);
- return NULL;
- }
- add_element(pool, element);
- }
return pool;
}
EXPORT_SYMBOL(mempool_create_node);
--
2.17.0