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 0A68FC77B73 for ; Thu, 20 Apr 2023 19:02:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231600AbjDTTCz (ORCPT ); Thu, 20 Apr 2023 15:02:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229625AbjDTTCw (ORCPT ); Thu, 20 Apr 2023 15:02:52 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 504DB1995 for ; Thu, 20 Apr 2023 12:02:51 -0700 (PDT) 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 0A215219DF; Thu, 20 Apr 2023 19:02:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1682017370; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wyOpH1UnQrvVJw6kWYdzta6t/ke0kX3oYrzbrP5nCuQ=; b=v1d+3DaMAllHzLN5tsGSUp+ae/unfKhbqg+TQFsgWHC+t4iTyrrUgFOp5USdxySWmOnw88 xrkk/1PF4C/qgKHJH2Q4s1IlBbXov5PXa3Mg8iea3F2Vl6oK7WhiygJvLuaVAbGnsc51xs 1b2KHd6La1ccwopUyNu3ZglA21e9Sss= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1682017370; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wyOpH1UnQrvVJw6kWYdzta6t/ke0kX3oYrzbrP5nCuQ=; b=NNsgpZgAKDpS40EAM3z4xvLFkP2uLB+Pl1kG6ul1+v08CNRiszf8icDRDKzWCnWrD34DSU J/BuQwFuLRia8NCA== 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 CDD0F1333C; Thu, 20 Apr 2023 19:02:49 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 7lVxMVmMQWTKQgAAMHmgww (envelope-from ); Thu, 20 Apr 2023 19:02:49 +0000 Date: Thu, 20 Apr 2023 21:02:39 +0200 From: David Sterba To: Linus Torvalds Cc: "Regzbot (on behalf of Thorsten Leemhuis)" , Rafael Wysocki , David Sterba , LKML , Linux regressions mailing list Subject: Re: Linux regressions report for mainline [2023-04-16] Message-ID: <20230420190239.GX19619@suse.cz> Reply-To: dsterba@suse.cz References: <168166781352.1843526.278570500979918184@leemhuis.info> <20230418182036.GS19619@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 18, 2023 at 12:11:51PM -0700, Linus Torvalds wrote: > On Tue, Apr 18, 2023 at 11:20 AM David Sterba wrote: > > > > There's also in-memory cache of already trimmed ranges since last mount > > so even running discard repeatedly (either fstrim or as mount option) > > will not do extra IO. We try hard not to provoke the firmware bugs. [...] > Again, that's libata - odd crazy hardware. But it's exactly the odd > crazy hardware that worries me. When the failure mode isn't "it's > slow", but "it ATE MY WHOLE DISK", that's a scary scary problem. > > Hmm? > > I dunno. Maybe you have reason to believe that all of these cases have > been fixed, or that some of these were caused by kernel bugs because > we did things wrong, and those have been fixed. > > But the failure modes just makes me worry. From your email, it *seems* > like you think that the failures were primarily performance-related. No, the main concern is if discard works without destroying data, performance is more like an optimization. I too worry about buggy hardware, we have a page just about that https://btrfs.readthedocs.io/en/latest/Hardware.html . I've taken notes from your reply and will enhance the page, or page about discard in particular. The info about device quirks/horkage could be linked too or I thought about generating a static page from the per-bus tables so it's on one page. I'll send pull request with fixes for the regression.