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From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH] nvme: set DMA_ATTR_WEAK_ORDERING attribute on dma buffers
Date: Sat, 17 Jun 2017 13:57:03 +0200	[thread overview]
Message-ID: <20170617115703.GA13002@lst.de> (raw)
In-Reply-To: <1497645290-31041-1-git-send-email-alan.adamson@oracle.com>

On Fri, Jun 16, 2017@01:34:50PM -0700, Alan Adamson wrote:
> SPARC based platforms suffer significant read performance penalties for
> nvme reads when Relaxed Ordering is not enabled. This change sets the
> DMA_ATTR_WEAK_ORDERING (Relaxed Ordering) attribute for nvme block dma
> buffers.

Please explain what it does exactly, and why you think it's safe for NVMe,
as that belongs into the changelog.

Bonus points for explaining why DMA_ATTR_WEAK_ORDERING shouldn't
be the default behavior for the dma_map_ routines instead of sprinkling
it over just about every driver..

  reply	other threads:[~2017-06-17 11:57 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-16 20:34 [PATCH] nvme: set DMA_ATTR_WEAK_ORDERING attribute on dma buffers Alan Adamson
2017-06-17 11:57 ` Christoph Hellwig [this message]
2017-06-21 20:30   ` Alan Adamson
     [not found]     ` <6a32f30b-433a-9857-164f-1717405a6082-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2017-06-24  7:35       ` DMA_ATTR_WEAK_ORDERING defintion, was " Christoph Hellwig
2017-06-24  7:35         ` Christoph Hellwig
2017-06-24  7:35         ` Christoph Hellwig
2017-06-26  9:15         ` Arnd Bergmann
2017-06-26  9:15           ` Arnd Bergmann
2017-06-27 20:46         ` chris hyser
2017-06-27 20:46           ` chris hyser
2017-07-05 19:07           ` Christoph Hellwig
2017-07-05 19:07             ` Christoph Hellwig
     [not found]             ` <20170705190714.GA7107-jcswGhMUV9g@public.gmane.org>
2017-07-10 16:17               ` chris hyser
2017-07-10 16:17                 ` chris hyser
2017-07-10 16:17                 ` chris hyser

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