From: Keith Busch <kbusch@kernel.org>
To: linux-nvme@lists.infradead.org, hch@lst.de, sagi@grimberg.me
Cc: Keith Busch <kbusch@kernel.org>
Subject: [PATCH] nvme: set dma alignment to qword
Date: Wed, 20 May 2020 19:22:53 -0700 [thread overview]
Message-ID: <20200521022253.3268324-1-kbusch@kernel.org> (raw)
The default dma alignment mask is 511, which is much larger than any nvme
controller requires. NVMe controllers accept qword aligned DMA addresses,
so set the request_queue constraints to that. This can help avoid bounce
buffers on user passthrough commands.
Signed-off-by: Keith Busch <kbusch@kernel.org>
---
drivers/nvme/host/core.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 805d289e6cd9..ba860efd250d 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2283,6 +2283,7 @@ static void nvme_set_queue_limits(struct nvme_ctrl *ctrl,
blk_queue_max_segments(q, min_t(u32, max_segments, USHRT_MAX));
}
blk_queue_virt_boundary(q, ctrl->page_size - 1);
+ blk_queue_dma_alignment(q, 7);
if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
vwc = true;
blk_queue_write_cache(q, vwc, vwc);
--
2.24.1
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next reply other threads:[~2020-05-21 2:23 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-21 2:22 Keith Busch [this message]
2020-05-21 6:05 ` [PATCH] nvme: set dma alignment to qword Sagi Grimberg
2020-05-21 15:28 ` Keith Busch
2020-05-21 15:29 ` Christoph Hellwig
2020-05-21 15:41 ` Keith Busch
2020-05-21 15:42 ` Christoph Hellwig
2020-05-21 19:46 ` James Smart
2020-05-26 14:53 ` Christoph Hellwig
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