From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from picard.linux.it (picard.linux.it [213.254.12.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 60D7EEDE998 for ; Thu, 14 Sep 2023 09:00:02 +0000 (UTC) Received: from picard.linux.it (localhost [IPv6:::1]) by picard.linux.it (Postfix) with ESMTP id 84BB43CE733 for ; Thu, 14 Sep 2023 10:59:59 +0200 (CEST) Received: from in-2.smtp.seeweb.it (in-2.smtp.seeweb.it [217.194.8.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) server-digest SHA384) (No client certificate requested) by picard.linux.it (Postfix) with ESMTPS id B08A13CB291 for ; Thu, 14 Sep 2023 10:59:48 +0200 (CEST) Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by in-2.smtp.seeweb.it (Postfix) with ESMTPS id 67341602BAC for ; Thu, 14 Sep 2023 10:59:46 +0200 (CEST) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 13D1C21887; Thu, 14 Sep 2023 08:59:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1694681985; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=xar5aASVzItjmU+UQHARuSaIZLKjh5MYNpT5TQn7dq4=; b=pT7JCGFZz/UDTFty9bAyZneQvsn2yuWo4NUcQrCx/3L6MNyFjmCKs2sKUzq+c4nE2PQrKD skEzs3D0YAiZP5cZN35nacsK9Zv5dTbhMBmo9I7IjfAWhTlbDZJ33NwTmCyrqAE5CwbkUY lpD/Gp2weGJW+c92Q0VltRM52Ip857o= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1694681985; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=xar5aASVzItjmU+UQHARuSaIZLKjh5MYNpT5TQn7dq4=; b=C/t8LfLgEIvYaDSWfp9t3Y5FToMMlSkt403b82BUaOb/eNdCiN3pY1yeV9eTeoma1Cf75l QDwW84k2lqHlxkBg== Received: from g78 (rpalethorpe.tcp.ovpn1.nue.suse.de [10.163.17.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id B40F52C142; Thu, 14 Sep 2023 08:59:44 +0000 (UTC) References: <20230803015149.69906-1-iwienand@redhat.com> <20230808035641.364676-2-iwienand@redhat.com> <87il8xhr05.fsf@suse.de> <65af05ae-bfd1-8153-4662-1bf61be855f3@suse.cz> <845ca8fe-1ae2-13ba-c9e0-a53cf953c0ff@suse.cz> <87r0n2gip5.fsf@suse.de> User-agent: mu4e 1.10.7; emacs 29.1 From: Richard Palethorpe To: Ian Wienand Date: Thu, 14 Sep 2023 08:37:46 +0100 Organization: Linux Private Site In-reply-to: Message-ID: <87msxpgmf4.fsf@suse.de> MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 1.0.1 at in-2.smtp.seeweb.it X-Virus-Status: Clean Subject: Re: [LTP] [PATCH v2] kernel/device-drivers/zram/zram01.sh : don't fill from /dev/zero X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: rpalethorpe@suse.de Cc: ltp@lists.linux.it Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" Hello, Ian Wienand writes: > On Wed, Sep 13, 2023 at 03:35:18PM +0100, Richard Palethorpe wrote: >> I would suggest just using sync, but Petr originally suggested using a >> wait loop. Then reported that the bug was still reproducible with the >> loop: >> >> https://lore.kernel.org/linux-block/Y3s+Czg8sBsGYO+1@pevik/ >> >> Then said it wasn't reproducible. The problem is that if using a loop >> doesn't solve it then possibly the VFAT meta-data doesn't get written to >> disk in the absence of any pressure. >> >> So instead I'd suggest resurrecting Petr's original patch or at least >> his approach. If we merge that and still see failures then maybe it's >> worth investigating more with tracing/debugging. > > I do not think the original patch [1] is the correct solution in light > of the further investigation that has happened after it was proposed. > > [2] is about the clearest explaination I can come up with, other than > the patch description and comments added in the v2 patch [3]. I am of > the opinion that to be useful these tests need to explicitly make sure > they are not just writing data that can be de-duplicated. I do not > believe the the intent of these tests was to have the only data > managed by the disk a very small amount of file-system metadata. > > Sorry to sound like a broken record, but I spent some time > investigating the paths taken with [2] and confirming the stats that > were coming out were not due to some kernel issue, but it really was > that the backing area had no pages allocated to it at all. > > Looping on a sync might make the test pass in more cases, but I hope > we can agree the idea is to make the test better, not just pass so we > can continue to ignore it. We don't want to remove coverage of ZRAM_SAME! A bug in ZRAM_SAME is a potential expoit or data-corruption. If you want to change the test you have to show where ZRAM_SAME is being covered instead. It's not that I think ZRAM_SAME is any more or less important than the true compression path. It's that if we never allow coverage to be swapped out or removed, then we systematically increase coverage. > > -i > > [1] https://lore.kernel.org/linux-block/20221107191136.18048-2-pvorel@suse.cz/ > [2] https://lore.kernel.org/linux-block/ZNB2kORYiKdl3vSq@fedora19.localdomain/ > [3] https://lore.kernel.org/ltp/ZPpOuK9lyWr2wZWI@fedora19.localdomain/T/#m1e037003252012ac115e57285a926db77380897f -- Thank you, Richard. -- Mailing list info: https://lists.linux.it/listinfo/ltp