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From: "Singh, Balbir" <sblbir@amazon.com>
To: "kbusch@kernel.org" <kbusch@kernel.org>
Cc: "axboe@fb.com" <axboe@fb.com>,
	"sblbir@amzn.com" <sblbir@amzn.com>, "hch@lst.de" <hch@lst.de>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
	"sagi@grimberg.me" <sagi@grimberg.me>
Subject: Re: [PATCH v2 2/2] nvme/host/core: Allow overriding of wait_ready timeout
Date: Tue, 17 Sep 2019 02:56:44 +0000	[thread overview]
Message-ID: <9612b87ed79704b89da559f42e3051ecb171a2ce.camel@amazon.com> (raw)
In-Reply-To: <20190917011441.GA31163@C02WT3WMHTD6>

On Mon, 2019-09-16 at 19:14 -0600, Keith Busch wrote:
> On Mon, Sep 16, 2019 at 09:04:31PM +0000, Singh, Balbir wrote:
> > I wonder if I should just call it debug_wait_ready_timeout and in the
> > comments about the help/description call out that this is a debug
> > feature.
> > 
> > What do you suggest?
> 
> I recommend going to the vendors that report incorrect timeout values, and
> apparently broken controllers that can't initialize, to have them fix
> both. If it doesn't initialize in 128 seconds, your only debugging
> recourse is to report to the vendor anyway; overriding the timeout to
> something under what the device reports it requires doesn't exactly
> provide you any additional debugging information.
> 

In my case I was doing a simple mirror (using madadm across two nvme
devices) and when I get timeouts on one, I need to wait up to 128 seconds
before switching over. Ideally I want this to be really fast and drop
the slow broken controller.

> If you really need the driver to do spec non-compliant behavior, we have
> quirks for that.

I like the quirks approach, but it assumes the timeout value is not
variable, but rather fixed by the quirk. I was attempting to really have
mirrored IO timeout quickly on a bad device.

Balbir Singh.



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  reply	other threads:[~2019-09-17  2:57 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-13 23:36 [PATCH v2 1/2] nvme/host/pci: Fix a race in controller removal Balbir Singh
2019-09-13 23:36 ` [PATCH v2 2/2] nvme/host/core: Allow overriding of wait_ready timeout Balbir Singh
2019-09-16  7:41   ` Christoph Hellwig
2019-09-16 12:33     ` Singh, Balbir
2019-09-16 16:01       ` hch
2019-09-16 21:04         ` Singh, Balbir
2019-09-17  1:14           ` Keith Busch
2019-09-17  2:56             ` Singh, Balbir [this message]
2019-09-17  3:17               ` Bart Van Assche
2019-09-17  5:02                 ` Singh, Balbir
2019-09-17 17:21                 ` James Smart
2019-09-17 20:08                   ` James Smart
2019-09-17  3:54               ` Keith Busch
2019-09-16  7:49 ` [PATCH v2 1/2] nvme/host/pci: Fix a race in controller removal Christoph Hellwig
2019-09-16 12:07   ` Singh, Balbir
2019-09-16 15:40 ` Bart Van Assche
2019-09-16 19:38   ` Singh, Balbir
2019-09-16 19:56     ` Bart Van Assche
2019-09-16 20:40       ` Singh, Balbir
2019-09-17 17:55         ` Bart Van Assche
2019-09-17 20:30           ` Keith Busch
2019-09-17 20:44           ` Singh, Balbir
2019-09-16 20:07     ` Keith Busch

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