[PATCH 2/4] nvme: don't poll the CQ from the kthread
From: hch@lst.de (Christoph Hellwig)
Date: 2016-02-29 14:59:45
Subsystem:
nvm express driver, the rest · Maintainers:
Keith Busch, Jens Axboe, Christoph Hellwig, Sagi Grimberg, Linus Torvalds
There is no reason to do unconditional polling of CQs per the NVMe spec. Signed-off-by: Christoph Hellwig <hch at lst.de> Reviewed-by: Keith Busch <keith.busch at intel.com> Reviewed-by: Sagi Grimberg <sagig at mellanox.com> Reviewed-by: Johannes Thumshirn <jthumshirn at suse.de> --- drivers/nvme/host/pci.c | 12 ------------ 1 file changed, 12 deletions(-)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 21b0be4..10839f7 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c@@ -1156,9 +1156,6 @@ static struct nvme_queue *nvme_alloc_queue(struct nvme_dev *dev, int qid, nvmeq->qid = qid; nvmeq->cq_vector = -1; dev->queues[qid] = nvmeq; - - /* make sure queue descriptor is set before queue count, for kthread */ - mb(); dev->queue_count++; return nvmeq;
@@ -1345,7 +1342,6 @@ static int nvme_kthread(void *data) set_current_state(TASK_INTERRUPTIBLE); spin_lock(&dev_list_lock); list_for_each_entry_safe(dev, next, &dev_list, node) { - int i; u32 csts = readl(dev->bar + NVME_REG_CSTS); /*
@@ -1363,14 +1359,6 @@ static int nvme_kthread(void *data) } continue; } - for (i = 0; i < dev->queue_count; i++) { - struct nvme_queue *nvmeq = dev->queues[i]; - if (!nvmeq) - continue; - spin_lock_irq(&nvmeq->q_lock); - nvme_process_cq(nvmeq); - spin_unlock_irq(&nvmeq->q_lock); - } } spin_unlock(&dev_list_lock); schedule_timeout(round_jiffies_relative(HZ));
--
2.1.4