* [PATCH] nvme-pci: remove last_sq_tail
@ 2020-04-27 18:54 Keith Busch
2020-04-29 0:07 ` Sagi Grimberg
2020-05-01 13:01 ` Christoph Hellwig
0 siblings, 2 replies; 3+ messages in thread
From: Keith Busch @ 2020-04-27 18:54 UTC (permalink / raw)
To: linux-nvme, hch, sagi; +Cc: Keith Busch
The nvme driver does not have enough tags to wrap the queue, and blk-mq
will no longer call commit_rqs() when there are no new submissions to
notify.
Signed-off-by: Keith Busch <kbusch@kernel.org>
---
drivers/nvme/host/pci.c | 23 ++++-------------------
1 file changed, 4 insertions(+), 19 deletions(-)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 4e79e412b276..8ebcf40f04fe 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -173,7 +173,6 @@ struct nvme_queue {
u16 q_depth;
u16 cq_vector;
u16 sq_tail;
- u16 last_sq_tail;
u16 cq_head;
u16 qid;
u8 cq_phase;
@@ -446,24 +445,11 @@ static int nvme_pci_map_queues(struct blk_mq_tag_set *set)
return 0;
}
-/*
- * Write sq tail if we are asked to, or if the next command would wrap.
- */
-static inline void nvme_write_sq_db(struct nvme_queue *nvmeq, bool write_sq)
+static inline void nvme_write_sq_db(struct nvme_queue *nvmeq)
{
- if (!write_sq) {
- u16 next_tail = nvmeq->sq_tail + 1;
-
- if (next_tail == nvmeq->q_depth)
- next_tail = 0;
- if (next_tail != nvmeq->last_sq_tail)
- return;
- }
-
if (nvme_dbbuf_update_and_check_event(nvmeq->sq_tail,
nvmeq->dbbuf_sq_db, nvmeq->dbbuf_sq_ei))
writel(nvmeq->sq_tail, nvmeq->q_db);
- nvmeq->last_sq_tail = nvmeq->sq_tail;
}
/**
@@ -480,7 +466,8 @@ static void nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd,
cmd, sizeof(*cmd));
if (++nvmeq->sq_tail == nvmeq->q_depth)
nvmeq->sq_tail = 0;
- nvme_write_sq_db(nvmeq, write_sq);
+ if (write_sq)
+ nvme_write_sq_db(nvmeq);
spin_unlock(&nvmeq->sq_lock);
}
@@ -489,8 +476,7 @@ static void nvme_commit_rqs(struct blk_mq_hw_ctx *hctx)
struct nvme_queue *nvmeq = hctx->driver_data;
spin_lock(&nvmeq->sq_lock);
- if (nvmeq->sq_tail != nvmeq->last_sq_tail)
- nvme_write_sq_db(nvmeq, true);
+ nvme_write_sq_db(nvmeq);
spin_unlock(&nvmeq->sq_lock);
}
@@ -1489,7 +1475,6 @@ static void nvme_init_queue(struct nvme_queue *nvmeq, u16 qid)
struct nvme_dev *dev = nvmeq->dev;
nvmeq->sq_tail = 0;
- nvmeq->last_sq_tail = 0;
nvmeq->cq_head = 0;
nvmeq->cq_phase = 1;
nvmeq->q_db = &dev->dbs[qid * 2 * dev->db_stride];
--
2.24.1
_______________________________________________
linux-nvme mailing list
linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] nvme-pci: remove last_sq_tail
2020-04-27 18:54 [PATCH] nvme-pci: remove last_sq_tail Keith Busch
@ 2020-04-29 0:07 ` Sagi Grimberg
2020-05-01 13:01 ` Christoph Hellwig
1 sibling, 0 replies; 3+ messages in thread
From: Sagi Grimberg @ 2020-04-29 0:07 UTC (permalink / raw)
To: Keith Busch, linux-nvme, hch
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
_______________________________________________
linux-nvme mailing list
linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] nvme-pci: remove last_sq_tail
2020-04-27 18:54 [PATCH] nvme-pci: remove last_sq_tail Keith Busch
2020-04-29 0:07 ` Sagi Grimberg
@ 2020-05-01 13:01 ` Christoph Hellwig
1 sibling, 0 replies; 3+ messages in thread
From: Christoph Hellwig @ 2020-05-01 13:01 UTC (permalink / raw)
To: Keith Busch; +Cc: hch, linux-nvme, sagi
On Mon, Apr 27, 2020 at 11:54:46AM -0700, Keith Busch wrote:
> The nvme driver does not have enough tags to wrap the queue, and blk-mq
> will no longer call commit_rqs() when there are no new submissions to
> notify.
Thanks,
applied.
_______________________________________________
linux-nvme mailing list
linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme
^ permalink raw reply [flat|nested] 3+ messages in thread
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