From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pa0-x22f.google.com ([2607:f8b0:400e:c03::22f]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZlnCS-0008HA-CJ for linux-mtd@lists.infradead.org; Tue, 13 Oct 2015 00:12:17 +0000 Received: by pabrc13 with SMTP id rc13so2222514pab.0 for ; Mon, 12 Oct 2015 17:11:55 -0700 (PDT) Date: Mon, 12 Oct 2015 17:11:53 -0700 From: Brian Norris To: Boris Brezillon Cc: Richard Weinberger , linux-mtd@lists.infradead.org, dwmw2@infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mtd: Add simple read disturb test Message-ID: <20151013001153.GS107187@google.com> References: <1427984026-31100-1-git-send-email-richard@nod.at> <20150402160451.GF32500@ld-irv-0074> <551D6BDA.6000606@nod.at> <20150412213120.0414fee5@bbrezillon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150412213120.0414fee5@bbrezillon> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Resurrecting this old thread, since it was mentioned at ELCE. On Sun, Apr 12, 2015 at 09:31:20PM +0200, Boris Brezillon wrote: > On Thu, 02 Apr 2015 18:18:34 +0200 > Richard Weinberger wrote: > > Am 02.04.2015 um 18:04 schrieb Brian Norris: > > > 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]. > > > > I've added the test to drivers/mtd/tests/ because it fits into. > > As simple as that. > > > > > 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. > > > > uninterruptibility got solved by my "[PATCH] mtd: Make MTD tests cancelable" patch. > > > > But if we want to kill drivers/mtd/tests/ I'll happily help out. > > I'd vote for that solution too. > I've looked at in-kernel mtd tests, and I'm pretty sure they can all be > done in userland. > This would prevent any kernel crash caused by buggy test modules. > > > Where shall we move these tests into? mtd-utils? > > I guess so, but I'll let Brian answer that one. > How about dispatching them in mtd-utils' tests/ directory (some of them > are NAND related tests, so creating a tests/nand would make sense, > and others are more generic). mtd-utils makes sense to me. If we're going to do this, let's make it a policy to not add more to drivers/mtd/tests/ then. For instance, this one [1]. Also, would we drop the in-kernel tests completely? If we make the move, we'd need to make sure to update the documentation (mtd-www.git). Brian [1] http://lists.infradead.org/pipermail/linux-mtd/2015-September/062237.html http://lists.infradead.org/pipermail/linux-mtd/2015-September/062236.html