From: Keith Busch <kbusch@kernel.org>
To: Eduard Hasenleithner <eduard@hasenleithner.at>
Cc: Sagi Grimberg <sagi@grimberg.me>, linux-nvme@lists.infradead.org
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: <20191106204329.GB32215@redsun51.ssa.fujisawa.hgst.com> (raw)
In-Reply-To: <f9e32847-00b1-59f5-8b15-860a94598e79@hasenleithner.at>
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
behavior.
> 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.
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next prev parent 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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