From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752746AbbDBQFF (ORCPT ); Thu, 2 Apr 2015 12:05:05 -0400 Received: from mail-pa0-f54.google.com ([209.85.220.54]:33172 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751780AbbDBQE7 (ORCPT ); Thu, 2 Apr 2015 12:04:59 -0400 Date: Thu, 2 Apr 2015 09:04:51 -0700 From: Brian Norris To: Richard Weinberger Cc: dwmw2@infradead.org, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mtd: Add simple read disturb test Message-ID: <20150402160451.GF32500@ld-irv-0074> References: <1427984026-31100-1-git-send-email-richard@nod.at> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1427984026-31100-1-git-send-email-richard@nod.at> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pa0-x233.google.com ([2607:f8b0:400e:c03::233]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YdhcP-0004as-Eg for linux-mtd@lists.infradead.org; Thu, 02 Apr 2015 16:05:22 +0000 Received: by padcy3 with SMTP id cy3so88234028pad.3 for ; Thu, 02 Apr 2015 09:04:59 -0700 (PDT) Date: Thu, 2 Apr 2015 09:04:51 -0700 From: Brian Norris To: Richard Weinberger Subject: Re: [PATCH] mtd: Add simple read disturb test Message-ID: <20150402160451.GF32500@ld-irv-0074> References: <1427984026-31100-1-git-send-email-richard@nod.at> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1427984026-31100-1-git-send-email-richard@nod.at> Cc: linux-mtd@lists.infradead.org, dwmw2@infradead.org, linux-kernel@vger.kernel.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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.