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 X-Spam-Level: X-Spam-Status: No, score=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0870FC4338F for ; Tue, 24 Aug 2021 03:24:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D2285611F0 for ; Tue, 24 Aug 2021 03:24:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233986AbhHXDYn (ORCPT ); Mon, 23 Aug 2021 23:24:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232605AbhHXDYm (ORCPT ); Mon, 23 Aug 2021 23:24:42 -0400 Received: from scorn.kernelslacker.org (scorn.kernelslacker.org [IPv6:2600:3c03:e000:2fb::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F02F1C061575 for ; Mon, 23 Aug 2021 20:23:58 -0700 (PDT) Received: from [2601:196:4600:6634:ae9e:17ff:feb7:72ca] (helo=wopr.kernelslacker.org) by scorn.kernelslacker.org with esmtp (Exim 4.92) (envelope-from ) id 1mIMvh-0001LI-6c; Mon, 23 Aug 2021 23:16:49 -0400 Received: by wopr.kernelslacker.org (Postfix, from userid 1026) id B5B2C56006F; Mon, 23 Aug 2021 23:16:48 -0400 (EDT) Date: Mon, 23 Aug 2021 23:16:48 -0400 From: Dave Jones To: Linux Kernel Cc: Peter Zijlstra , Johannes Weiner , Linus Torvalds Subject: 5.14-rc breaks iotop swap io monitoring. Message-ID: <20210824031648.GA2725@codemonkey.org.uk> Mail-Followup-To: Dave Jones , Linux Kernel , Peter Zijlstra , Johannes Weiner , Linus Torvalds MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I just noticed that in 5.14-rc running iotop, it complains on startup that "CONFIG_TASK_DELAY_ACCT not enabled in kernel, cannot determine SWAPIN and IO %" and sure enough a bunch of columns show up as 'unavailable'. My suspicion is this commit, which I've not confirmed yet as it doesn't cleanly revert. I'll poke at it some more in the morning, but figured I'd bring it up sans-evidence in the hope that I'll wake up to someone having an Ah-ha moment. Dave commit c5895d3f06cbb80ccb311f1dcb37074651030cb6 Author: Peter Zijlstra Date: Tue May 4 22:43:42 2021 +0200 sched: Simplify sched_info_on() The situation around sched_info is somewhat complicated, it is used by sched_stats and delayacct and, indirectly, kvm. If SCHEDSTATS=Y (but disabled by default) sched_info_on() is unconditionally true -- this is the case for all distro kernel configs I checked. If for some reason SCHEDSTATS=N, but TASK_DELAY_ACCT=Y, then sched_info_on() can return false when delayacct is disabled, presumably because there would be no other users left; except kvm is. Instead of complicating matters further by accurately accounting sched_stat and kvm state, simply unconditionally enable when SCHED_INFO=Y, matching the common distro case. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Thomas Gleixner Reviewed-by: Ingo Molnar Acked-by: Johannes Weiner Link: https://lkml.kernel.org/r/20210505111525.121458839@infradead.org