From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752108AbbDLTb1 (ORCPT ); Sun, 12 Apr 2015 15:31:27 -0400 Received: from down.free-electrons.com ([37.187.137.238]:37018 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751877AbbDLTb0 (ORCPT ); Sun, 12 Apr 2015 15:31:26 -0400 Date: Sun, 12 Apr 2015 21:31:20 +0200 From: Boris Brezillon To: Richard Weinberger Cc: Brian Norris , linux-mtd@lists.infradead.org, dwmw2@infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mtd: Add simple read disturb test Message-ID: <20150412213120.0414fee5@bbrezillon> In-Reply-To: <551D6BDA.6000606@nod.at> References: <1427984026-31100-1-git-send-email-richard@nod.at> <20150402160451.GF32500@ld-irv-0074> <551D6BDA.6000606@nod.at> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.23; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Richard, 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). Best Regards, Boris -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from down.free-electrons.com ([37.187.137.238] helo=mail.free-electrons.com) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1YhNbd-0003tb-9A for linux-mtd@lists.infradead.org; Sun, 12 Apr 2015 19:31:46 +0000 Date: Sun, 12 Apr 2015 21:31:20 +0200 From: Boris Brezillon To: Richard Weinberger Subject: Re: [PATCH] mtd: Add simple read disturb test Message-ID: <20150412213120.0414fee5@bbrezillon> In-Reply-To: <551D6BDA.6000606@nod.at> References: <1427984026-31100-1-git-send-email-richard@nod.at> <20150402160451.GF32500@ld-irv-0074> <551D6BDA.6000606@nod.at> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: dwmw2@infradead.org, Brian Norris , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Richard, 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). Best Regards, Boris -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com