From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from a.ns.miles-group.at ([95.130.255.143] helo=radon.swed.at) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZoHiX-0005MF-Fw for linux-mtd@lists.infradead.org; Mon, 19 Oct 2015 21:11:42 +0000 Subject: Re: [PATCH] mtd: Add simple read disturb test To: Brian Norris , Boris Brezillon References: <1427984026-31100-1-git-send-email-richard@nod.at> <20150402160451.GF32500@ld-irv-0074> <551D6BDA.6000606@nod.at> <20150412213120.0414fee5@bbrezillon> <20151013001153.GS107187@google.com> Cc: linux-mtd@lists.infradead.org, dwmw2@infradead.org, linux-kernel@vger.kernel.org, Daniel Walter From: Richard Weinberger Message-ID: <56255C73.60501@nod.at> Date: Mon, 19 Oct 2015 23:11:15 +0200 MIME-Version: 1.0 In-Reply-To: <20151013001153.GS107187@google.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Am 13.10.2015 um 02:11 schrieb Brian Norris: > 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? I agree. Ripping out in-kernel tests and moving them to mtd-utils seems legit to me. While we're here, re-factoring existing tests in mtd-utils would also be nice. I'm also thinking of making UBI tests more user friendly such that distros can package them into their mtd-utils package. > 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 Thanks, //richard