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Re: [net-next PATCH RFC 19/26] arch/sparc: Add option to skip DMA sync as a part of map and unmap

From David Miller <davem@davemloft.net>
Newsgroups linux.kernel
Subject Re: [net-next PATCH RFC 19/26] arch/sparc: Add option to skip DMA sync as a part of map and unmap
Date 2016-10-24 20:30 +0200
Message-ID <svSau-2UD-41@gated-at.bofh.it> (permalink)
References <svRR7-2Kt-9@gated-at.bofh.it> <svRR8-2Kt-45@gated-at.bofh.it>
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From: Alexander Duyck <alexander.h.duyck@intel.com>
Date: Mon, 24 Oct 2016 08:06:07 -0400

> This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
> avoid invoking cache line invalidation if the driver will just handle it
> via a sync_for_cpu or sync_for_device call.
> 
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: sparclinux@vger.kernel.org
> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>

This is fine for avoiding the flush for performance reasons, but the
chip isn't going to write anything back unless the device wrote into
the area.

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Thread

[net-next PATCH RFC 19/26] arch/sparc: Add option to skip DMA sync  as a part of map and unmap Alexander Duyck <alexander.h.duyck@intel.com> - 2016-10-24 20:10 +0200
  Re: [net-next PATCH RFC 19/26] arch/sparc: Add option to skip DMA  sync as a part of map and unmap David Miller <davem@davemloft.net> - 2016-10-24 20:30 +0200
    Re: [net-next PATCH RFC 19/26] arch/sparc: Add option to skip DMA  sync as a part of map and unmap Alexander Duyck <alexander.duyck@gmail.com> - 2016-10-24 21:40 +0200

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