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From: Ming Lei <ming.lei@canonical.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH 0/2] dma-unmap: allow to only unmap completed DMA buffer
Date: Tue, 28 May 2013 00:13:05 +0800	[thread overview]
Message-ID: <1369671187-24430-1-git-send-email-ming.lei@canonical.com> (raw)

This patchset tries to loose the check on DMA buffer size in check_unmap()
of dma-debug first, then only unmap the actual completed DMA buffer in USB
unmap path.

Considered that DMA unmapping often runs in hard irq context, the patch set
may save irq handling time. And the improvement can be observed on
ARMv7(Pandaboard) with the chage, at average ~25us is saved about ehci irq
handling under usbnet ping test case.

Thanks,
--
Ming Lei



             reply	other threads:[~2013-05-27 16:13 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-27 16:13 Ming Lei [this message]
2013-05-27 16:13 ` [RFC PATCH 1/2] dma-debug: allow size to become smaller in dma_unmap Ming Lei
2013-05-27 20:37   ` Alexander Duyck
2013-05-27 16:13 ` [PATCH 2/2] USB: hcd: only unmap the actual completed DMA buffer Ming Lei
2013-05-27 17:13   ` Sergei Shtylyov
2013-05-27 20:18 ` [RFC PATCH 0/2] dma-unmap: allow to only unmap " Alan Stern

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