From patchwork Mon Mar 29 18:12:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 411092 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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS autolearn=no 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 B7EF9C433E0 for ; Mon, 29 Mar 2021 18:38:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83A416198E for ; Mon, 29 Mar 2021 18:38:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231645AbhC2SiN (ORCPT ); Mon, 29 Mar 2021 14:38:13 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:60208 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231479AbhC2Shm (ORCPT ); Mon, 29 Mar 2021 14:37:42 -0400 Received: from localhost (127.0.0.1) (HELO v370.home.net.pl) by /usr/run/smtp (/usr/run/postfix/private/idea_relay_lmtp) via UNIX with SMTP (IdeaSmtpServer 2.0.3) id 291421c0a50beb6e; Mon, 29 Mar 2021 20:37:41 +0200 Received: from kreacher.localnet (89-64-81-131.dynamic.chello.pl [89.64.81.131]) (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 v370.home.net.pl (Postfix) with ESMTPSA id 5480F669165; Mon, 29 Mar 2021 20:37:40 +0200 (CEST) From: "Rafael J. Wysocki" To: Linux PM Cc: LKML , Frederic Weisbecker , Peter Zijlstra , Thomas Gleixner , "Zhou Ti (x2019cwm)" Subject: [PATCH v1 0/5] cpuidle: Take possible negative "sleep length" values into account Date: Mon, 29 Mar 2021 20:12:39 +0200 Message-ID: <2764850.e9J7NaK4W3@kreacher> MIME-Version: 1.0 X-VADE-SPAMSTATE: clean X-VADE-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeduledrudehkedguddvlecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfjqffogffrnfdpggftiffpkfenuceurghilhhouhhtmecuudehtdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephffvufffkfgggfgtsehtufertddttdejnecuhfhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqnecuggftrfgrthhtvghrnhepvdevgfetueetheekudeuvdduteelvefftdfftdejjeeukeffteeikefgiefghedunecuffhomhgrihhnpehkvghrnhgvlhdrohhrghenucfkphepkeelrdeigedrkedurddufedunecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepkeelrdeigedrkedurddufedupdhhvghlohepkhhrvggrtghhvghrrdhlohgtrghlnhgvthdpmhgrihhlfhhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqpdhrtghpthhtoheplhhinhhugidqphhmsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtohepfhhrvgguvghrihgtsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehpvghtvghriiesihhnfhhrrgguvggrugdrohhrghdprhgtphhtthhopehtghhlgies lhhinhhuthhrohhnihigrdguvgdprhgtphhtthhopeigvddtudeltgifmhesshhtfhigrdgtrg X-DCC--Metrics: v370.home.net.pl 1024; Body=6 Fuz1=6 Fuz2=6 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi All, As follows from the discussion triggered by the patch at https://lore.kernel.org/lkml/20210311123708.23501-2-frederic@kernel.org/ the cpuidle governors using tick_nohz_get_sleep_length() assume it to always return positive values which is not correct in general. To address this issues, first document the fact that negative values can be returned by tick_nohz_get_sleep_length() (patch [1/5]). Then, in preparation for more substantial changes, change the data type of two fields in struct cpuidle_state to s64 so they can be used in computations involving negative numbers safely (patch [2/5]). Next, adjust the teo governor a bit so that negative "sleep length" values are counted like zero by it (patch [3/5]) and modify it so as to avoid mishandling negative "sleep length" values (patch [4/5]). Finally, make the menu governor take negative "sleep length" values into account properly (patch [5/5]). Please see the changelogs of the patches for details. Thanks!