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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F85BC43219 for ; Tue, 22 Nov 2022 15:07:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233942AbiKVPHm (ORCPT ); Tue, 22 Nov 2022 10:07:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234027AbiKVPHc (ORCPT ); Tue, 22 Nov 2022 10:07:32 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3097A13CF2; Tue, 22 Nov 2022 07:07:30 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id C75EC21D3E; Tue, 22 Nov 2022 15:07:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1669129648; 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=p56F2nwME/RWURtSP2TSQAQXPWOVxd9VX0H+uS1eGS0=; b=vuXrQNe9cPzsddLz3LepnRY7WjGBC2hwqmeAZKHW2mROYJ+vEC/3MyEuYK6J+FbxDozZEm 3segnSrLYCCTBO93SzOf8Ltn3wF/GcoR3rdoo9VdYNi5IePV3twf3X9QV69NrvRNMQYzbP n1lrJXRS3YN9Glh8ZQGjpKAm6Mi0c6E= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1669129648; 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=p56F2nwME/RWURtSP2TSQAQXPWOVxd9VX0H+uS1eGS0=; b=GdC4hcnByfHfq5j9HOMxZvYvdEKAheoNPOxrH4K22oVhTseS4ITfKbDFlWzzX1TK2Cjf+X LZVb/9aXKFcYVcAw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id EAD6613B01; Tue, 22 Nov 2022 15:07:26 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id +6QnMq7lfGM6CwAAMHmgww (envelope-from ); Tue, 22 Nov 2022 15:07:26 +0000 Date: Tue, 22 Nov 2022 16:07:24 +0100 From: Petr Vorel To: Martin Doucha Cc: Sergey Senozhatsky , Minchan Kim , ltp@lists.linux.it, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Nitin Gupta , Jens Axboe , OGAWA Hirofumi , Yang Xu Subject: Re: [PATCH 0/1] Possible bug in zram on ppc64le on vfat Message-ID: Reply-To: Petr Vorel References: <20221107191136.18048-1-pvorel@suse.cz> <3ac740c0-954b-5e68-b413-0adc7bc5a2b5@suse.cz> <9489dd1c-012c-8b5d-b670-a27213da287a@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9489dd1c-012c-8b5d-b670-a27213da287a@suse.cz> Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org > On 11. 11. 22 1:48, Sergey Senozhatsky wrote: > > On (22/11/10 15:29), Martin Doucha wrote: > > > I've tried to debug the issue and collected some interesting data (all > > > values come from zram device with 25M size limit and zstd compression > > > algorithm): > > > - mm_stat values are correct after mkfs.vfat: > > > 65536 220 65536 26214400 65536 0 0 0 > > > - mm_stat values stay correct after mount: > > > 65536 220 65536 26214400 65536 0 0 0 > > > - the bug is triggered by filling the filesystem to capacity (using dd): > > > 4194304 0 0 26214400 327680 64 0 0 > > Can you try using /dev/urandom for dd, not /dev/zero? > > Do you still see zeroes in sysfs output or some random values? > After 50 test runs on a kernel where the issue is confirmed, I could not > reproduce the failure while filling the device from /dev/urandom instead of > /dev/zero. The test reported compression ratio around 1.8-2.5 which means > the memory usage reported by mm_stat was 10-13MB. Martin, thanks a lot for reruning tests. I wonder problems on /dev/zero is a kernel bug or just problem which should be workarounded. > Note that I had to disable the other filesystems in the test because some of > them kept failing with compression ratio <1. Yes, I noted that as well at least on exfat and btrfs (if I remember correctly). It wouldn't be a problem to just use it for vfat if we agreed test should be modified. Kind regards, Petr