From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: hch@lst.de, linux-nvme@lists.infradead.org, sagi@grimberg.me
Subject: Re: [PATCH 2/3] nvme-pci: remove cached shadow doorbell offsets
Date: Fri, 1 May 2020 14:54:20 +0200 [thread overview]
Message-ID: <20200501125420.GB5197@lst.de> (raw)
In-Reply-To: <20200427235243.2268765-2-kbusch@kernel.org>
This doesn't actually apply. Some comments below anyway:
> +static bool nvme_dbbuf_update_sq(struct nvme_queue *nvmeq)
> +{
> + struct nvme_dev *dev = nvmeq->dev;
>
> + if (!dev->dbbuf_dbs)
> + return true;
I'd rather have this check in the caller. That makes it both more
obvious to read, and avoids a function call for the fast path.
> +static bool nvme_dbbuf_update_cq(struct nvme_queue *nvmeq)
> +{
> + struct nvme_dev *dev = nvmeq->dev;
> +
> + if (!dev->dbbuf_dbs)
> + return true;
Same here.
> static inline void nvme_write_sq_db(struct nvme_queue *nvmeq)
> {
> + if (nvme_dbbuf_update_sq(nvmeq))
> writel(nvmeq->sq_tail, nvmeq->q_db);
> }
It might be worth to just open code this in the two callers, even
if the additional check I suggested above.
>
> @@ -918,11 +918,8 @@ static inline bool nvme_cqe_pending(struct nvme_queue *nvmeq)
>
> static inline void nvme_ring_cq_doorbell(struct nvme_queue *nvmeq)
> {
> + if (nvme_dbbuf_update_cq(nvmeq))
> + writel(nvmeq->cq_head, nvmeq->q_db + nvmeq->dev->db_stride);
Same here for the only caller.
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next prev parent reply other threads:[~2020-05-01 12:54 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-27 23:52 [PATCH 1/3] nvme-pci: clear shadow doorbell memory on resets Keith Busch
2020-04-27 23:52 ` [PATCH 2/3] nvme-pci: remove cached shadow doorbell offsets Keith Busch
2020-04-30 6:36 ` Dongli Zhang
2020-04-30 19:07 ` Keith Busch
2020-05-01 12:54 ` Christoph Hellwig [this message]
2021-10-04 9:42 ` John Levon
2020-04-27 23:52 ` [PATCH 3/3] nvme-pci: reshuffle nvme_queue members Keith Busch
2020-05-01 12:57 ` Christoph Hellwig
2020-05-01 15:08 ` Keith Busch
2020-05-01 15:12 ` Christoph Hellwig
2020-05-01 15:23 ` Keith Busch
2020-05-04 18:18 ` Keith Busch
2020-05-01 12:49 ` [PATCH 1/3] nvme-pci: clear shadow doorbell memory on resets Christoph Hellwig
2021-10-04 9:35 ` John Levon
2021-10-06 12:07 ` Keith Busch
2021-10-06 16:05 ` John Levon
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