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From: Keith Busch <>
To: Eduard Hasenleithner <>
Cc: Sagi Grimberg <>,
Subject: Re: [RFC PATCH] Workaround for discard on non-conformant nvme devices
Date: Thu, 7 Nov 2019 05:43:29 +0900	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Wed, Nov 06, 2019 at 09:22:00PM +0100, Eduard Hasenleithner wrote:
> On 06.11.19 19:23, Keith Busch wrote:
> > > This needs to come with a quirk for it.
> > 
> > Yeah, and have the broken ones to use the ctrl->discard_page so that you
> > don't need to worry about the alignment of the address kmalloc returns.
> This raises some questions for me.
> Why bother maintaining a quirk list and have additional complexity with
> separate code paths?

It documents the code on why the driver is doing spec non-compliant

> Couldn't we just simply use the discard_page for all discards?

That's normally just a fallback to ensure forward progress under memory
pressure. It's not particularly performant, though.

> Are there even nvme devices out there which have conformant behavior in this
> respect?

I believe most of them do conform, but I don't have a large sample size
to confirm.

Linux-nvme mailing list

  reply	other threads:[~2019-11-06 20:43 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-04 21:47 [RFC PATCH] Workaround for discard on non-conformant nvme devices Eduard Hasenleithner
2019-11-06 16:52 ` Sagi Grimberg
2019-11-06 18:23   ` Keith Busch
2019-11-06 20:22     ` Eduard Hasenleithner
2019-11-06 20:43       ` Keith Busch [this message]
2019-11-06 21:10         ` Eduard Hasenleithner
2019-11-06 21:34           ` Keith Busch

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