lightnvm: pblk: simplify work_queue mempool

In pblk, we have a mempool to allocate a generic structure that we
pass along workqueues. This is heavily used in the GC path in order
to have enough inflight reads and fully utilize the GC bandwidth.

However, the current GC path copies data to the host memory and puts it
back into the write buffer. This requires a vmalloc allocation for the
data and a memory copy. Thus, guaranteeing the allocation by using a
mempool for the structure in itself does not give us much. Until we
implement support for vector copy to avoid moving data through the host,
just allocate the workqueue structure using kmalloc.

This allows us to have a much smaller mempool.

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 16 insertions, 16 deletions

diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index 7b1f29c71338..340552253580 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -20,7 +20,7 @@
 
 #include "pblk.h"
 
-static struct kmem_cache *pblk_blk_ws_cache, *pblk_rec_cache, *pblk_g_rq_cache,
+static struct kmem_cache *pblk_ws_cache, *pblk_rec_cache, *pblk_g_rq_cache,
                                 *pblk_w_rq_cache, *pblk_line_meta_cache;
 static DECLARE_RWSEM(pblk_lock);
 struct bio_set *pblk_bio_set;
@@ -184,9 +184,9 @@ static int pblk_init_global_caches(struct pblk *pblk)
         char cache_name[PBLK_CACHE_NAME_LEN];
 
         down_write(&pblk_lock);
-        pblk_blk_ws_cache = kmem_cache_create("pblk_blk_ws",
+        pblk_ws_cache = kmem_cache_create("pblk_blk_ws",
                                 sizeof(struct pblk_line_ws), 0, 0, NULL);
-        if (!pblk_blk_ws_cache) {
+        if (!pblk_ws_cache) {
                 up_write(&pblk_lock);
                 return -ENOMEM;
         }
@@ -194,7 +194,7 @@ static int pblk_init_global_caches(struct pblk *pblk)
         pblk_rec_cache = kmem_cache_create("pblk_rec",
                                 sizeof(struct pblk_rec_ctx), 0, 0, NULL);
         if (!pblk_rec_cache) {
-                kmem_cache_destroy(pblk_blk_ws_cache);
+                kmem_cache_destroy(pblk_ws_cache);
                 up_write(&pblk_lock);
                 return -ENOMEM;
         }
@@ -202,7 +202,7 @@ static int pblk_init_global_caches(struct pblk *pblk)
         pblk_g_rq_cache = kmem_cache_create("pblk_g_rq", pblk_g_rq_size,
                                 0, 0, NULL);
         if (!pblk_g_rq_cache) {
-                kmem_cache_destroy(pblk_blk_ws_cache);
+                kmem_cache_destroy(pblk_ws_cache);
                 kmem_cache_destroy(pblk_rec_cache);
                 up_write(&pblk_lock);
                 return -ENOMEM;
@@ -211,7 +211,7 @@ static int pblk_init_global_caches(struct pblk *pblk)
         pblk_w_rq_cache = kmem_cache_create("pblk_w_rq", pblk_w_rq_size,
                                 0, 0, NULL);
         if (!pblk_w_rq_cache) {
-                kmem_cache_destroy(pblk_blk_ws_cache);
+                kmem_cache_destroy(pblk_ws_cache);
                 kmem_cache_destroy(pblk_rec_cache);
                 kmem_cache_destroy(pblk_g_rq_cache);
                 up_write(&pblk_lock);
@@ -223,7 +223,7 @@ static int pblk_init_global_caches(struct pblk *pblk)
         pblk_line_meta_cache = kmem_cache_create(cache_name,
                                 pblk->lm.sec_bitmap_len, 0, 0, NULL);
         if (!pblk_line_meta_cache) {
-                kmem_cache_destroy(pblk_blk_ws_cache);
+                kmem_cache_destroy(pblk_ws_cache);
                 kmem_cache_destroy(pblk_rec_cache);
                 kmem_cache_destroy(pblk_g_rq_cache);
                 kmem_cache_destroy(pblk_w_rq_cache);
@@ -246,20 +246,20 @@ static int pblk_core_init(struct pblk *pblk)
         if (pblk_init_global_caches(pblk))
                 return -ENOMEM;
 
-        /* internal bios can be at most the sectors signaled by the device. */
+        /* Internal bios can be at most the sectors signaled by the device. */
         pblk->page_bio_pool = mempool_create_page_pool(nvm_max_phys_sects(dev),
                                                                         0);
         if (!pblk->page_bio_pool)
                 return -ENOMEM;
 
-        pblk->line_ws_pool = mempool_create_slab_pool(PBLK_WS_POOL_SIZE,
-                                                        pblk_blk_ws_cache);
-        if (!pblk->line_ws_pool)
+        pblk->gen_ws_pool = mempool_create_slab_pool(PBLK_GEN_WS_POOL_SIZE,
+                                                        pblk_ws_cache);
+        if (!pblk->gen_ws_pool)
                 goto free_page_bio_pool;
 
         pblk->rec_pool = mempool_create_slab_pool(geo->nr_luns, pblk_rec_cache);
         if (!pblk->rec_pool)
-                goto free_blk_ws_pool;
+                goto free_gen_ws_pool;
 
         pblk->g_rq_pool = mempool_create_slab_pool(PBLK_READ_REQ_POOL_SIZE,
                                                         pblk_g_rq_cache);
@@ -308,8 +308,8 @@ free_g_rq_pool:
         mempool_destroy(pblk->g_rq_pool);
 free_rec_pool:
         mempool_destroy(pblk->rec_pool);
-free_blk_ws_pool:
-        mempool_destroy(pblk->line_ws_pool);
+free_gen_ws_pool:
+        mempool_destroy(pblk->gen_ws_pool);
 free_page_bio_pool:
         mempool_destroy(pblk->page_bio_pool);
         return -ENOMEM;
@@ -324,13 +324,13 @@ static void pblk_core_free(struct pblk *pblk)
                 destroy_workqueue(pblk->bb_wq);
 
         mempool_destroy(pblk->page_bio_pool);
-        mempool_destroy(pblk->line_ws_pool);
+        mempool_destroy(pblk->gen_ws_pool);
         mempool_destroy(pblk->rec_pool);
         mempool_destroy(pblk->g_rq_pool);
         mempool_destroy(pblk->w_rq_pool);
         mempool_destroy(pblk->line_meta_pool);
 
-        kmem_cache_destroy(pblk_blk_ws_cache);
+        kmem_cache_destroy(pblk_ws_cache);
         kmem_cache_destroy(pblk_rec_cache);
         kmem_cache_destroy(pblk_g_rq_cache);
         kmem_cache_destroy(pblk_w_rq_cache);