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, 7 insertions, 6 deletions

diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index f5fbb9a46784..b92532211866 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -33,7 +33,8 @@ static void pblk_mark_bb(struct pblk *pblk, struct pblk_line *line,
 		pr_err("pblk: attempted to erase bb: line:%d, pos:%d\n",
 							line->id, pos);
 
-	pblk_line_run_ws(pblk, NULL, ppa, pblk_line_mark_bb, pblk->bb_wq);
+	pblk_gen_run_ws(pblk, NULL, ppa, pblk_line_mark_bb,
+						GFP_ATOMIC, pblk->bb_wq);
 }
 
 static void __pblk_end_io_erase(struct pblk *pblk, struct nvm_rq *rqd)
@@ -1623,7 +1624,7 @@ void pblk_line_close_ws(struct work_struct *work)
 	struct pblk_line *line = line_ws->line;
 
 	pblk_line_close(pblk, line);
-	mempool_free(line_ws, pblk->line_ws_pool);
+	mempool_free(line_ws, pblk->gen_ws_pool);
 }
 
 void pblk_line_mark_bb(struct work_struct *work)
@@ -1648,16 +1649,16 @@ void pblk_line_mark_bb(struct work_struct *work)
 	}
 
 	kfree(ppa);
-	mempool_free(line_ws, pblk->line_ws_pool);
+	mempool_free(line_ws, pblk->gen_ws_pool);
 }
 
-void pblk_line_run_ws(struct pblk *pblk, struct pblk_line *line, void *priv,
-		      void (*work)(struct work_struct *),
+void pblk_gen_run_ws(struct pblk *pblk, struct pblk_line *line, void *priv,
+		      void (*work)(struct work_struct *), gfp_t gfp_mask,
 		      struct workqueue_struct *wq)
 {
 	struct pblk_line_ws *line_ws;
 
-	line_ws = mempool_alloc(pblk->line_ws_pool, GFP_ATOMIC);
+	line_ws = mempool_alloc(pblk->gen_ws_pool, gfp_mask);
 	if (!line_ws)
 		return;