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=-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 F1F3AC433E0 for ; Wed, 10 Mar 2021 02:01:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD17A64FE4 for ; Wed, 10 Mar 2021 02:01:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230303AbhCJCBD (ORCPT ); Tue, 9 Mar 2021 21:01:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230325AbhCJCA4 (ORCPT ); Tue, 9 Mar 2021 21:00:56 -0500 X-Greylist: delayed 306 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 09 Mar 2021 18:00:56 PST Received: from vulcan.kevinlocke.name (vulcan.kevinlocke.name [IPv6:2001:19f0:5:727:1e84:17da:7c52:5ab4]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2061EC06174A; Tue, 9 Mar 2021 18:00:56 -0800 (PST) Received: from kevinolos.kevinlocke.name (host-69-145-60-23.bln-mt.client.bresnan.net [69.145.60.23]) (Authenticated sender: kevin@kevinlocke.name) by vulcan.kevinlocke.name (Postfix) with ESMTPSA id EC6F0210A6DC; Wed, 10 Mar 2021 01:55:48 +0000 (UTC) Received: by kevinolos.kevinlocke.name (Postfix, from userid 1000) id 89D311300698; Tue, 9 Mar 2021 18:55:46 -0700 (MST) Date: Tue, 9 Mar 2021 18:55:46 -0700 From: Kevin Locke To: Jens Axboe Cc: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [v5.12-rc2 regression] io_uring: high CPU use after suspend-to-ram Message-ID: Mail-Followup-To: Kevin Locke , Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org With kernel 5.12-rc2 (and torvalds/master 144c79ef3353), if mpd is playing or paused when my system is suspended-to-ram, when the system is resumed mpd will consume ~200% CPU until killed. It continues to produce audio and respond to pause/play commands, which do not affect CPU usage. This occurs with either pulse (to PulseAudio or PipeWire-as-PulseAudio) or alsa audio_output. The issue appears to have been introduced by a combination of two commits: 3bfe6106693b caused freeze on suspend-to-ram when mpd is paused or playing. e4b4a13f4941 fixed suspend-to-ram, but introduced the high CPU on resume. I attempted to further diagnose using `perf record -p $(pidof mpd)`. Running for about a minute after resume shows ~280 MMAP2 events and almost nothing else. I'm not sure what to make of that or how to further investigate. Let me know if there's anything else I can do to help diagnose/test. Thanks, Kevin