From: Kai Heng Feng <kai.heng.feng@canonical.com>
To: Keith Busch <kbusch@kernel.org>
Cc: "Mario.Limonciello@dell.com" <Mario.Limonciello@dell.com>,
"hch@lst.de" <hch@lst.de>, "axboe@fb.com" <axboe@fb.com>,
"sagi@grimberg.me" <sagi@grimberg.me>,
"rafael@kernel.org" <rafael@kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"Wysocki, Rafael J" <rafael.j.wysocki@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"Busch, Keith" <keith.busch@intel.com>
Subject: Re: [PATCH] nvme-pci: Use non-operational power state instead of D3 on Suspend-to-Idle
Date: Fri, 10 May 2019 23:18:52 +0800 [thread overview]
Message-ID: <D2D197AF-0072-42AC-A844-8D6BC9677949@canonical.com> (raw)
In-Reply-To: <20190510140209.GG9675@localhost.localdomain>
> On May 10, 2019, at 10:02 PM, Keith Busch <kbusch@kernel.org> wrote:
>
> On Thu, May 09, 2019 at 11:05:42PM -0700, Kai-Heng Feng wrote:
>> Yes, that’ what I was told by the NVMe vendor, so all I know is to impose a
>> memory barrier.
>> If mb() shouldn’t be used here, what’s the correct variant to use in this
>> context?
>
> I'm afraid the requirement is still not clear to me. AFAIK, all our
> barriers routines ensure data is visible either between CPUs, or between
> CPU and devices. The CPU never accesses HMB memory, so there must be some
> other reasoning if this barrier is a real requirement for this device.
Sure, I’ll ask vendor what that MemRd is for.
Kai-Heng
next prev parent reply other threads:[~2019-05-10 15:18 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-08 18:59 [PATCH] nvme-pci: Use non-operational power state instead of D3 on Suspend-to-Idle Kai-Heng Feng
2019-05-08 19:15 ` Chaitanya Kulkarni
2019-05-08 19:16 ` Keith Busch
2019-05-08 19:30 ` Kai-Heng Feng
2019-05-08 19:38 ` Mario.Limonciello
2019-05-08 19:51 ` Christoph Hellwig
2019-05-08 20:28 ` Mario.Limonciello
2019-05-09 6:12 ` Christoph Hellwig
2019-05-09 6:48 ` Kai-Heng Feng
2019-05-09 6:52 ` Christoph Hellwig
2019-05-09 9:19 ` Rafael J. Wysocki
2019-05-09 9:25 ` Christoph Hellwig
2019-05-09 20:48 ` Rafael J. Wysocki
2019-05-09 9:07 ` Rafael J. Wysocki
2019-05-09 9:42 ` Kai-Heng Feng
2019-05-09 9:56 ` Christoph Hellwig
2019-05-09 10:28 ` Kai-Heng Feng
2019-05-09 10:31 ` Christoph Hellwig
2019-05-09 11:59 ` Kai-Heng Feng
2019-05-09 18:57 ` Mario.Limonciello
2019-05-09 19:28 ` Keith Busch
2019-05-09 20:54 ` Rafael J. Wysocki
2019-05-09 21:16 ` Keith Busch
2019-05-09 21:39 ` Rafael J. Wysocki
2019-05-09 21:37 ` Mario.Limonciello
2019-05-09 21:54 ` Keith Busch
2019-05-09 22:19 ` Mario.Limonciello
2019-05-10 6:05 ` Kai-Heng Feng
2019-05-10 8:23 ` Rafael J. Wysocki
2019-05-10 13:52 ` Keith Busch
2019-05-10 15:15 ` Kai Heng Feng
2019-05-10 15:36 ` Keith Busch
2019-05-10 14:02 ` Keith Busch
2019-05-10 15:18 ` Kai Heng Feng [this message]
2019-05-10 15:49 ` hch
2019-05-10 5:30 ` Christoph Hellwig
2019-05-10 13:51 ` Keith Busch
2019-05-09 16:20 ` Keith Busch
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