From: Randy Dunlap <randy.dunlap@oracle.com>
To: adharmap@codeaurora.org
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
dwalker@codeaurora.org, Arnd Bergmann <arnd@arndb.de>,
FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>, Joerg Roedel <joerg.roedel@amd.com>,
Maciej Sosnowski <maciej.sosnowski@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Becky Bruce <beckyb@kernel.crashing.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Yang Hongyang <yanghy@cn.fujitsu.com>,
linux-arch@vger.kernel.org,
Abhijeet Dharmapurikar <adharmap@quicinc.com>
Subject: Re: [RFC PATCH] dma: Add barrierless dma mapping/unmapping api
Date: Tue, 26 Jan 2010 08:48:59 -0800 [thread overview]
Message-ID: <20100126084859.d33904d3.randy.dunlap@oracle.com> (raw)
In-Reply-To: <1264473346-32721-1-git-send-email-adharmap@codeaurora.org>
On Mon, 25 Jan 2010 18:35:46 -0800 adharmap@codeaurora.org wrote:
> From: Abhijeet Dharmapurikar <adharmap@quicinc.com>
>
> Tests have shown that there is a significant performance gain
> when a driver uses mapping/unmapping functions without a barrier
> multiple times and calls dsb() only after the last buffer. This
> api adds support for barrierless dma operations on ARMv6
> and ARMv7.
>
> Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
> ---
>
> Please refer to the earlier post here http://lkml.org/lkml/2010/1/4/347.
> These changes only are only for the arm v6 and v7
> architecture and introduce dma_map/unmap_single_nobarrier api.
> The idea is to extend the cpu_cache_fns.dma_.*_range functions to accept
> a third boolean argument that tells it whether to execute the barrier or
> skip it. Note that this applies over Linux 2.6.33-rc5 and needs a few changes
> to apply on the linux-next tree.
>
>
> arch/arm/include/asm/cacheflush.h | 12 ++++----
> arch/arm/include/asm/dma-mapping.h | 57 ++++++++++++++++++++++++++++++++++--
> arch/arm/mm/cache-v6.S | 15 ++++++----
> arch/arm/mm/cache-v7.S | 19 +++++++++++-
> arch/arm/mm/dma-mapping.c | 17 ++++++-----
> drivers/staging/dream/pmem.c | 4 +-
> 6 files changed, 97 insertions(+), 27 deletions(-)
Along with the other comments, the patch is also missing updates
to Documentation/DMA-API.txt ...
---
~Randy
prev parent reply other threads:[~2010-01-26 16:49 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-26 2:35 [RFC PATCH] dma: Add barrierless dma mapping/unmapping api adharmap
2010-01-26 4:30 ` Benjamin Herrenschmidt
2010-01-26 4:43 ` FUJITA Tomonori
2010-01-26 20:11 ` Abhijeet Dharmapurikar
2010-01-27 5:19 ` FUJITA Tomonori
2010-01-27 6:49 ` Benjamin Herrenschmidt
2010-01-26 16:48 ` Randy Dunlap [this message]
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