null_blk: use ppa_cache pool

Instead of using a page pool, we can save memory by only allocating room
for 64 entries for the ppa command. Introduce a ppa_cache to allocate only
the required memory for the ppa list.

Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Matias Bjørling 2015-11-19 12:50:08 +01:00 committed by Jens Axboe
parent 6824c5ef5e
commit 6bb9535bc3

View File

@ -47,6 +47,7 @@ static LIST_HEAD(nullb_list);
static struct mutex lock;
static int null_major;
static int nullb_indexes;
static struct kmem_cache *ppa_cache;
struct completion_queue {
struct llist_head list;
@ -521,7 +522,7 @@ static void *null_lnvm_create_dma_pool(struct request_queue *q, char *name)
{
mempool_t *virtmem_pool;
virtmem_pool = mempool_create_page_pool(64, 0);
virtmem_pool = mempool_create_slab_pool(64, ppa_cache);
if (!virtmem_pool) {
pr_err("null_blk: Unable to create virtual memory pool\n");
return NULL;
@ -767,6 +768,12 @@ static int __init null_init(void)
bs = PAGE_SIZE;
}
if (use_lightnvm && bs != 4096) {
pr_warn("null_blk: LightNVM only supports 4k block size\n");
pr_warn("null_blk: defaults block size to 4k\n");
bs = 4096;
}
if (use_lightnvm && queue_mode != NULL_Q_MQ) {
pr_warn("null_blk: LightNVM only supported for blk-mq\n");
pr_warn("null_blk: defaults queue mode to blk-mq\n");
@ -803,15 +810,27 @@ static int __init null_init(void)
if (null_major < 0)
return null_major;
if (use_lightnvm) {
ppa_cache = kmem_cache_create("ppa_cache", 64 * sizeof(u64),
0, 0, NULL);
if (!ppa_cache) {
pr_err("null_blk: unable to create ppa cache\n");
return -ENOMEM;
}
}
for (i = 0; i < nr_devices; i++) {
if (null_add_dev()) {
unregister_blkdev(null_major, "nullb");
return -EINVAL;
goto err_ppa;
}
}
pr_info("null: module loaded\n");
return 0;
err_ppa:
kmem_cache_destroy(ppa_cache);
return -EINVAL;
}
static void __exit null_exit(void)
@ -826,6 +845,8 @@ static void __exit null_exit(void)
null_del_dev(nullb);
}
mutex_unlock(&lock);
kmem_cache_destroy(ppa_cache);
}
module_init(null_init);