Re: [PATCH] mtd: Add simple read disturb test

From: Brian Norris <computersforpeace@gmail.com>
To: Richard Weinberger <richard@nod.at>
Cc: dwmw2@infradead.org, linux-mtd@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mtd: Add simple read disturb test
Date: Thu, 2 Apr 2015 09:04:51 -0700	[thread overview]
Message-ID: <20150402160451.GF32500@ld-irv-0074> (raw)
In-Reply-To: <1427984026-31100-1-git-send-email-richard@nod.at>

On Thu, Apr 02, 2015 at 04:13:46PM +0200, Richard Weinberger wrote:
> This simple MTD tests allows the user to see when read disturb happens.
> By reading blocks over and over it reports flipped bits.
> Currently it reports only flipped bits of the worst page of a block.
> If within block X page P1 has 3 bit flips and P6 4, it will report 4.
> By default every 50th block is read.

Didn't read through this much yet, but why do we need another in-kernel
test that coul (AFAICT) be easily replicated in userspace? The same goes
for several of the other tests, I think, actually. But at least with
those, we have a history of keeping them around, so it's not too much
burden [1].

Brian

[1] Although there are some latent issues in these tests that are still
getting get worked out (e.g., bad handling of 64-bit casting; too large
of stacks; uninterruptibility). The latter two would not even exist if
we were in user space.