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From: Takao Indoh <indou.takao@fujitsu.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <keith.busch@intel.com>,
	Takao Indoh <indou.takao@jp.fujitsu.com>, <axboe@fb.com>,
	<sagi@grimberg.me>, <linux-nvme@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] nvme: Enable acceleration feature of A64FX processor
Date: Wed, 13 Feb 2019 21:03:58 +0900	[thread overview]
Message-ID: <20190213120358.GA3559@esprimo> (raw)
In-Reply-To: <20190205161347.GA847@lst.de>

On Tue, Feb 05, 2019 at 05:13:47PM +0100, Christoph Hellwig wrote:
> On Tue, Feb 05, 2019 at 07:39:06AM -0700, Keith Busch wrote:
> > > Standard PCIe devices can use Relaxed Ordering (RO) by setting Attr
> > > field in the TLP header, however, this mechanism cannot be utilized if
> > > the device does not support RO feature. Fujitsu A64FX processor has an
> > > alternate feature to enable RO in its Root Port by setting the bit 56 of
> > > DMA address. This mechanism enables to utilize RO feature even if the
> > > device does not support standard PCIe RO.
> > 
> > I think you're better of just purchasing devices that support the
> > capability per spec rather than with a non-standard work around.
> 
> Agreed, this seems like a pretty gross hack.

Ok, let me think about how I should change this patch.
I'm thinking that the problem of this patch is adding processor specific
code into NVMe common driver, is this correct? Or another problem? It
would be great if you could give me a hint to improve this patch.

Thanks,
Takao Indoh


  reply	other threads:[~2019-02-13 12:04 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-01 12:46 [PATCH] nvme: Enable acceleration feature of A64FX processor Takao Indoh
2019-02-01 14:54 ` Keith Busch
2019-02-05 12:56   ` Takao Indoh
2019-02-05 14:39     ` Keith Busch
2019-02-05 16:13       ` Christoph Hellwig
2019-02-13 12:03         ` Takao Indoh [this message]
2019-02-14 17:11           ` Christoph Hellwig
2019-02-14 20:44       ` Elliott, Robert (Persistent Memory)
2019-02-14 21:17         ` Keith Busch
2019-02-20  9:46         ` Takao Indoh
2019-02-22 17:07           ` Keith Busch
2019-02-01 15:51 ` Christoph Hellwig
2019-02-05 12:56   ` Takao Indoh

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