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 766B0C433EF for ; Wed, 23 Feb 2022 11:53:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240201AbiBWLxv (ORCPT ); Wed, 23 Feb 2022 06:53:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235966AbiBWLxs (ORCPT ); Wed, 23 Feb 2022 06:53:48 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 84C3E57B1A; Wed, 23 Feb 2022 03:53:20 -0800 (PST) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 40A3F1F43D; Wed, 23 Feb 2022 11:53:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1645617199; h=from:from: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=lHKLDcXaApTqsl2KQS4V+/Sm+LIozq5sgKx8GXifXUE=; b=egv/jm8RvovquqsfWcuJRwBtKBVUu7OVZoV08A97BI/bojJrZKRGrPOawsaSoFdwUgRrJ1 Y8yOK1HZXCJlxhkg+3ItPW4f4Y7L7OGxC1fDYlJbmwORfiSY2i+owYRWiMkGiTWKBIJNSz GYOIjG7+B3d4gYXjP41jiRgKBHjUWo8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1645617199; h=from:from: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=lHKLDcXaApTqsl2KQS4V+/Sm+LIozq5sgKx8GXifXUE=; b=DjQTeQ5j1zEB52lzsMsHmvZJjvTFizTsSZHs11jPamrSA1NDxfM+1XbJwJl372CHKtWIq6 AgOLK5j3rK2xnAAA== Received: from quack3.suse.cz (unknown [10.163.28.18]) (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 308D7A3B81; Wed, 23 Feb 2022 11:53:19 +0000 (UTC) Received: by quack3.suse.cz (Postfix, from userid 1000) id 67980A0605; Wed, 23 Feb 2022 12:53:13 +0100 (CET) Date: Wed, 23 Feb 2022 12:53:13 +0100 From: Jan Kara To: Ritesh Harjani Cc: Jan Kara , linux-ext4@vger.kernel.org, Harshad Shirwadkar , Theodore Ts'o , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC 3/9] ext4: Add couple of more fast_commit tracepoints Message-ID: <20220223115313.3s73bu7p454bodvl@quack3.lan> References: <90608d31b7ad8500c33d875d3a7fa50e3456dc1a.1645558375.git.riteshh@linux.ibm.com> <20220223094057.53zcovnazrqwbngw@quack3.lan> <20220223101159.ekwbylvbmec5v35q@riteshh-domain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220223101159.ekwbylvbmec5v35q@riteshh-domain> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 23-02-22 15:41:59, Ritesh Harjani wrote: > On 22/02/23 10:40AM, Jan Kara wrote: > > On Wed 23-02-22 02:04:11, Ritesh Harjani wrote: > > > This adds two more tracepoints for ext4_fc_track_template() & > > > ext4_fc_cleanup() which are helpful in debugging some fast_commit issues. > > > > > > Signed-off-by: Ritesh Harjani > > > > So why is this more useful than trace_ext4_fc_track_range() and other > > tracepoints? I don't think it provides any more information? What am I > > missing? > > Thanks Jan for all the reviews. > > So ext4_fc_track_template() adds almost all required information > (including the caller info) in this one trace point along with transaction tid > which is useful for tracking issue similar to what is mentioned in Patch-9. > > (race with if inode is part of two transactions tid where jbd2 full commit > may begin for txn n-1 while inode is still in sbi->s_fc_q[MAIN]) I understand commit tid is interesting but cannot we just add it to tracepoints like trace_ext4_fc_track_range() directly? It would seem useful to have it there and when it is there, the need for ext4_fc_track_template() is not really big. I don't care too much but this tracepoint looked a bit superfluous to me. > And similarly ext4_fc_cleanup() helps with that information about which tid > completed and whether it was called from jbd2 full commit or from fast_commit. Yeah, that one is clear. Honza -- Jan Kara SUSE Labs, CR