On 11/11/2015 02:27 PM, Jens Axboe wrote:
On 11/11/2015 03:06 AM, Matias Bjørling wrote:
Add support for registering as a LightNVM device. This allows us to
evaluate the performance of the LightNVM library.
In /drivers/Makefile, LightNVM is moved above block device drivers
to make sure that the LightNVM media managers have been initialized
before drivers under /drivers/block are initialized.
Generally looks ok. One question:
+static void *null_lnvm_create_dma_pool(struct request_queue *q, char
*name)
+{
+ mempool_t *virtmem_pool;
+
+ ppa_cache = kmem_cache_create(name, PAGE_SIZE, 0, 0, NULL);
+ if (!ppa_cache) {
+ pr_err("null_nvm: Unable to create kmem cache\n");
+ return NULL;
+ }
+
+ virtmem_pool = mempool_create_slab_pool(64, ppa_cache);
+ if (!virtmem_pool) {
+ pr_err("null_nvm: Unable to create virtual memory pool\n");
+ return NULL;
+ }
+
+ return virtmem_pool;
+}
Why create a slab cache if it's pages? Why not just have the mempool
alloc/free alloc single pages?
Ala attached. Also fixes a leak of not freeing the ppa_cache slab cache.
Did you try and load/reload the module? I'm thinking it would have crashed.
--
Jens Axboe
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index 1efaef6e54e9..31d5debc020e 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -446,8 +446,6 @@ static void null_del_dev(struct nullb *nullb)
#ifdef CONFIG_NVM
-static struct kmem_cache *ppa_cache;
-
static void null_lnvm_end_io(struct request *rq, int error)
{
struct nvm_rq *rqd = rq->end_io_data;
@@ -523,13 +521,7 @@ static void *null_lnvm_create_dma_pool(struct request_queue *q, char *name)
{
mempool_t *virtmem_pool;
- ppa_cache = kmem_cache_create(name, PAGE_SIZE, 0, 0, NULL);
- if (!ppa_cache) {
- pr_err("null_nvm: Unable to create kmem cache\n");
- return NULL;
- }
-
- virtmem_pool = mempool_create_slab_pool(64, ppa_cache);
+ virtmem_pool = mempool_create_page_pool(64, 0);
if (!virtmem_pool) {
pr_err("null_nvm: Unable to create virtual memory pool\n");
return NULL;
@@ -540,10 +532,8 @@ static void *null_lnvm_create_dma_pool(struct request_queue *q, char *name)
static void null_lnvm_destroy_dma_pool(void *pool)
{
- mempool_t *virtmem_pool = pool;
+ mempool_destroy(pool);
- mempool_destroy(virtmem_pool);
-}
static void *null_lnvm_dev_dma_alloc(struct request_queue *q, void *pool,
gfp_t mem_flags, dma_addr_t *dma_handler)
