From: "santosh.shilimkar@oracle.com" <santosh.shilimkar@oracle.com>
To: Bart Van Assche <bart.vanassche@sandisk.com>,
Doug Ledford <dledford@redhat.com>
Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/9] IB: Optimize DMA mapping
Date: Tue, 10 Jan 2017 17:28:14 -0800 [thread overview]
Message-ID: <320aa1cd-8110-2724-a43d-514efc386127@oracle.com> (raw)
In-Reply-To: <20170111005648.14988-1-bart.vanassche@sandisk.com>
On 1/10/17 4:56 PM, Bart Van Assche wrote:
> Hello Doug,
>
> As you know there are two sets of DMA mapping operations in the Linux
> kernel:
> - One set of DMA mapping operations that is used by most drivers.
> - Another set of DMA mapping operations that is only used by the RDMA
> drivers.
> Having two sets of DMA mapping operations is not only a source of
> confusion but also a source of unnecessary overhead. The DMA mapping
> operations are in the hot path so it is important that the overhead
> of these operations is as low as possible. Hence this patch series
> that converts the RDMA code to the standard DMA mapping API and
> thereby eliminates the if (dev->dma_ops) test from the hot path. An
> additional benefit is that the size of HW and SW drivers that do not
> use DMA is reduced by switching to dma_virt_ops.
>
This is really good series. I was always wondering why the extra
indirection was added first place on streaming APIs.
Regards,
Santosh
prev parent reply other threads:[~2017-01-11 3:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-11 0:56 Bart Van Assche
2017-01-11 0:56 ` [PATCH 3/9] dma: Add dma_virt_ops Bart Van Assche
2017-01-11 8:56 ` Christoph Hellwig
2017-01-12 0:07 ` Bart Van Assche
2017-01-11 0:56 ` [PATCH 4/9] IB/hf1: Remove DMA mapping code Bart Van Assche
2017-01-11 0:56 ` [PATCH 5/9] IB/qib: " Bart Van Assche
2017-01-12 13:15 ` Leon Romanovsky
2017-01-11 0:56 ` [PATCH 6/9] IB: Use dma_virt_ops instead of duplicating it Bart Van Assche
2017-01-12 13:17 ` Leon Romanovsky
2017-01-11 0:56 ` [PATCH 7/9] RDS: IB: Remove an unused structure member Bart Van Assche
2017-01-11 1:21 ` santosh.shilimkar
2017-01-11 0:56 ` [PATCH 8/9] IB: Convert ib_dma_*_coherent() argument type from u64 into dma_addr_t Bart Van Assche
2017-01-12 13:12 ` Leon Romanovsky
2017-01-11 0:56 ` [PATCH 9/9] treewide: Inline ib_dma_map_*() functions Bart Van Assche
2017-01-12 11:45 ` Sagi Grimberg
2017-01-12 13:09 ` Leon Romanovsky
2017-01-11 1:28 ` santosh.shilimkar [this message]
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