bcache: Give btree_io_wq correct semantics again

commit d797bd9897e3559eb48d68368550d637d32e468c upstream.

Before killing `btree_io_wq`, the queue was allocated using
`create_singlethread_workqueue()` which has `WQ_MEM_RECLAIM`. After
killing it, it no longer had this property but `system_wq` is not
single threaded.

Let's combine both worlds and make it multi threaded but able to
reclaim memory.

Cc: Coly Li <colyli@suse.de>
Cc: stable@vger.kernel.org # 5.4+
Signed-off-by: Kai Krakow <kai@kaishome.de>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 952f022..fe6dce1 100644 (file)
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -2775,7 +2775,7 @@ void bch_btree_exit(void)
 
 int __init bch_btree_init(void)
 {
-       btree_io_wq = create_singlethread_workqueue("bch_btree_io");
+       btree_io_wq = alloc_workqueue("bch_btree_io", WQ_MEM_RECLAIM, 0);
        if (!btree_io_wq)
                return -ENOMEM;