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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 505EDC4320A for ; Wed, 18 Aug 2021 11:08:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3078061058 for ; Wed, 18 Aug 2021 11:08:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235292AbhHRLJK (ORCPT ); Wed, 18 Aug 2021 07:09:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234913AbhHRLJE (ORCPT ); Wed, 18 Aug 2021 07:09:04 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 515DBC061764; Wed, 18 Aug 2021 04:08:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=xF3XSQocGKr3XFWdPGOP9gXsahAr6PzRo/gjqi7SrQw=; b=elMK4wMFZCS7zOtF3Kqr6Qx0Ts BvtKhauM9WXNcWGqt3xyFwwLDMmg90XOftPK1TKxNZ0ElZqghYwMSu3VOshfKq4mJu1NEJYfOIlYP 8cerDUID75lFIm370aWtQuziRuBEoaeDNezJSUJel6Yl3VVLphnSA+Rd20hQ/ylzHco+tr15iyuwt 7OgloetCQ4m6OvROCo+b4zZLTBFME+nvxfRaOMPCK6tmOmz4n2Ro40g9DgtqcHiugbFqYN1GBXPkD 52RPR8u0bGSmYe20+e/zG6OCtyDULgROSbjweT1C1NdTWbBzQ/+ZYma2siK9FR6AMQmH2Nx0WL2if cDwJNvXg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mGJOb-003k4v-97; Wed, 18 Aug 2021 11:06:19 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 859E53012AD; Wed, 18 Aug 2021 13:06:08 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 6CF20200FBAE0; Wed, 18 Aug 2021 13:06:08 +0200 (CEST) Date: Wed, 18 Aug 2021 13:06:08 +0200 From: Peter Zijlstra To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , Quentin Perret , Tejun Heo , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , "Rafael J. Wysocki" , Dietmar Eggemann , Daniel Bristot de Oliveira , Valentin Schneider , Mark Rutland , kernel-team@android.com Subject: Re: [PATCH v11 08/16] sched: Allow task CPU affinity to be restricted on asymmetric systems Message-ID: References: <20210730112443.23245-1-will@kernel.org> <20210730112443.23245-9-will@kernel.org> <20210818104227.GA13828@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210818104227.GA13828@willie-the-truck> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 18, 2021 at 11:42:28AM +0100, Will Deacon wrote: > Ah, sorry. I didn't realise you couldn't _free_ with a raw lock held in RT. > Is there somewhere I can read up on that? It's because the allocators use spinlock_t, which cannot nest inside raw_spinlock_t.