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 DDED5C43334 for ; Thu, 9 Jun 2022 09:48:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242955AbiFIJse (ORCPT ); Thu, 9 Jun 2022 05:48:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242882AbiFIJsU (ORCPT ); Thu, 9 Jun 2022 05:48:20 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21F3E23A3D8; Thu, 9 Jun 2022 02:48:19 -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=9jA4mchnYQoJ5XaXo73/qgoc6iaW5C3P1k7XaYKsS1U=; b=cB9XFjQVxWqfDyzeN0qaxTZuLD YLcvVXkDGRGNOtMLtEgH+zL1QwGa+jRQrKiDu6o+KwcqUIios781clMIKdQSQtEcXojjpXyjmvj46 euyjd4m+n/z+pXAWpiww5AHKVJISuO8dbwfn2kdK+vnbm4iQMh9u58KvobfYp6DKnGfTofnM78Yt0 Jz76LJDB6p5dvl91aPCez/Dj+sFAkswEne+HjI0PWGc0G7Uh6QasF9s0y9AlvQ8RjyVaUQ4ilXQ62 Z4qivKfe5pGVxrpCjV/g6X6ndctS6ICj5/6oYIabFd8D02kUsNuFDdK3DNDO+pifvTslSQOhwvIep NfI5oq7A==; Received: from dhcp-077-249-017-003.chello.nl ([77.249.17.3] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzEli-00DR5Q-VZ; Thu, 09 Jun 2022 09:47:59 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 100CA981287; Thu, 9 Jun 2022 11:47:58 +0200 (CEST) Date: Thu, 9 Jun 2022 11:47:57 +0200 From: Peter Zijlstra To: Tony Lindgren Cc: Arnd Bergmann , Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King - ARM Linux , Hans Ulli Kroll , Linus Walleij , Shawn Guo , Sascha Hauer , Sascha Hauer , Fabio Estevam , NXP Linux Team , Kevin Hilman , Catalin Marinas , Will Deacon , Guo Ren , bcain@quicinc.com, Huacai Chen , Xuerui Wang , Geert Uytterhoeven , Sam Creasey , Michal Simek , Thomas Bogendoerfer , Dinh Nguyen , Jonas Bonn , Stefan Kristiansson , Stafford Horne , James Bottomley , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Paul Walmsley , Palmer Dabbelt , Albert Ou , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Yoshinori Sato , Rich Felker , David Miller , Richard Weinberger , Anton Ivanov , Johannes Berg , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , the arch/x86 maintainers , "H. Peter Anvin" , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Juergen Gross , srivatsa@csail.mit.edu, amakhalov@vmware.com, Pv-drivers , Boris Ostrovsky , Chris Zankel , Max Filippov , Rafael Wysocki , Len Brown , Pavel Machek , gregkh , Michael Turquette , Stephen Boyd , Daniel Lezcano , lpieralisi@kernel.org, Sudeep Holla , Andy Gross , Bjorn Andersson , Anup Patel , Thierry Reding , Jonathan Hunter , jacob.jun.pan@linux.intel.com, Yury Norov , Andy Shevchenko , Rasmus Villemoes , Steven Rostedt , Petr Mladek , Sergey Senozhatsky , John Ogness , "Paul E. McKenney" , Frederic Weisbecker , quic_neeraju@quicinc.com, Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , vschneid@redhat.com, jpoimboe@kernel.org, alpha , Linux Kernel Mailing List , "open list:SYNOPSYS ARC ARCHITECTURE" , Linux ARM , linux-omap , linux-csky@vger.kernel.org, "open list:QUALCOMM HEXAGON..." , "open list:IA64 (Itanium) PLATFORM" , linux-m68k , "open list:BROADCOM NVRAM DRIVER" , Openrisc , Parisc List , linuxppc-dev , linux-riscv , linux-s390 , Linux-sh list , sparclinux , linux-um , linux-perf-users@vger.kernel.org, "open list:DRM DRIVER FOR QEMU'S CIRRUS DEVICE" , xen-devel , "open list:TENSILICA XTENSA PORT (xtensa)" , ACPI Devel Maling List , Linux PM list , linux-clk , linux-arm-msm , "open list:TEGRA ARCHITECTURE SUPPORT" , linux-arch , rcu@vger.kernel.org Subject: Re: [PATCH 33/36] cpuidle,omap3: Use WFI for omap3_pm_idle() Message-ID: References: <20220608142723.103523089@infradead.org> <20220608144518.010587032@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org On Thu, Jun 09, 2022 at 10:39:22AM +0300, Tony Lindgren wrote: > * Arnd Bergmann [220608 18:18]: > > On Wed, Jun 8, 2022 at 4:27 PM Peter Zijlstra wrote: > > > > > > arch_cpu_idle() is a very simple idle interface and exposes only a > > > single idle state and is expected to not require RCU and not do any > > > tracing/instrumentation. > > > > > > As such, omap_sram_idle() is not a valid implementation. Replace it > > > with the simple (shallow) omap3_do_wfi() call. Leaving the more > > > complicated idle states for the cpuidle driver. > > Agreed it makes sense to limit deeper idle states to cpuidle. Hopefully > there is some informative splat for attempting to use arch_cpu_ide() > for deeper idle states :) The arch_cpu_idle() interface doesn't allow one to express a desire for deeper states. I'm not sure how anyone could even attempt this. But given what OMAP needs to go deeper, this would involve things that require RCU, combine that with the follow up patches that rip out all the trace_.*_rcuidle() hackery from the power and clock domain code, PROVE_RCU should scream if anybody were to attempt it. 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7B900C433EF for ; Thu, 9 Jun 2022 09:48:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=veeXq83x5FQH2oscQNBCCVM5KWUul1JLA4GsjDg7ZJE=; b=JciBtpV1MY52x3 y1ZLs8MEM2txxCm3k0LrYlDonDzrwoIaVS6NI1+qnLMZHiHG8DSbNRDIgIVs9KvPFHvrhkwkZzNgF 542N97Yn2zeECFLxEkWqve0rYlu+TieMZHb6xGKwWyD8u/TjSSulOxeVf43QZa2W5InCm/eRlK6aW 5+GGhttZcQjHyvoO5PgoATTHsXNGIjQxLBPa3ttoJyRqzUSIWVLYyWKoQd3+psyzlK1Pr0LrDUaVr jWPelEkTAHqwxOfPCssI+NMZIqMGqy06rDoSGusN45R/4izWISmFBsWgwt4pQVTeQgoC8OmqXGFOd HuyBHdHbgynKdRM4rBBQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzElx-000m9p-EX; Thu, 09 Jun 2022 09:48:13 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzElv-000m8u-Ck; Thu, 09 Jun 2022 09:48:11 +0000 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=9jA4mchnYQoJ5XaXo73/qgoc6iaW5C3P1k7XaYKsS1U=; b=cB9XFjQVxWqfDyzeN0qaxTZuLD YLcvVXkDGRGNOtMLtEgH+zL1QwGa+jRQrKiDu6o+KwcqUIios781clMIKdQSQtEcXojjpXyjmvj46 euyjd4m+n/z+pXAWpiww5AHKVJISuO8dbwfn2kdK+vnbm4iQMh9u58KvobfYp6DKnGfTofnM78Yt0 Jz76LJDB6p5dvl91aPCez/Dj+sFAkswEne+HjI0PWGc0G7Uh6QasF9s0y9AlvQ8RjyVaUQ4ilXQ62 Z4qivKfe5pGVxrpCjV/g6X6ndctS6ICj5/6oYIabFd8D02kUsNuFDdK3DNDO+pifvTslSQOhwvIep NfI5oq7A==; Received: from dhcp-077-249-017-003.chello.nl ([77.249.17.3] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzElj-00DR5R-4H; Thu, 09 Jun 2022 09:47:59 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 100CA981287; Thu, 9 Jun 2022 11:47:58 +0200 (CEST) Date: Thu, 9 Jun 2022 11:47:57 +0200 From: Peter Zijlstra To: Tony Lindgren Cc: Arnd Bergmann , Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King - ARM Linux , Hans Ulli Kroll , Linus Walleij , Shawn Guo , Sascha Hauer , Sascha Hauer , Fabio Estevam , NXP Linux Team , Kevin Hilman , Catalin Marinas , Will Deacon , Guo Ren , bcain@quicinc.com, Huacai Chen , Xuerui Wang , Geert Uytterhoeven , Sam Creasey , Michal Simek , Thomas Bogendoerfer , Dinh Nguyen , Jonas Bonn , Stefan Kristiansson , Stafford Horne , James Bottomley , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Paul Walmsley , Palmer Dabbelt , Albert Ou , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Yoshinori Sato , Rich Felker , David Miller , Richard Weinberger , Anton Ivanov , Johannes Berg , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , the arch/x86 maintainers , "H. Peter Anvin" , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Juergen Gross , srivatsa@csail.mit.edu, amakhalov@vmware.com, Pv-drivers , Boris Ostrovsky , Chris Zankel , Max Filippov , Rafael Wysocki , Len Brown , Pavel Machek , gregkh , Michael Turquette , Stephen Boyd , Daniel Lezcano , lpieralisi@kernel.org, Sudeep Holla , Andy Gross , Bjorn Andersson , Anup Patel , Thierry Reding , Jonathan Hunter , jacob.jun.pan@linux.intel.com, Yury Norov , Andy Shevchenko , Rasmus Villemoes , Steven Rostedt , Petr Mladek , Sergey Senozhatsky , John Ogness , "Paul E. McKenney" , Frederic Weisbecker , quic_neeraju@quicinc.com, Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , vschneid@redhat.com, jpoimboe@kernel.org, alpha , Linux Kernel Mailing List , "open list:SYNOPSYS ARC ARCHITECTURE" , Linux ARM , linux-omap , linux-csky@vger.kernel.org, "open list:QUALCOMM HEXAGON..." , "open list:IA64 (Itanium) PLATFORM" , linux-m68k , "open list:BROADCOM NVRAM DRIVER" , Openrisc , Parisc List , linuxppc-dev , linux-riscv , linux-s390 , Linux-sh list , sparclinux , linux-um , linux-perf-users@vger.kernel.org, "open list:DRM DRIVER FOR QEMU'S CIRRUS DEVICE" , xen-devel , "open list:TENSILICA XTENSA PORT (xtensa)" , ACPI Devel Maling List , Linux PM list , linux-clk , linux-arm-msm , "open list:TEGRA ARCHITECTURE SUPPORT" , linux-arch , rcu@vger.kernel.org Subject: Re: [PATCH 33/36] cpuidle,omap3: Use WFI for omap3_pm_idle() Message-ID: References: <20220608142723.103523089@infradead.org> <20220608144518.010587032@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+linux-snps-arc=archiver.kernel.org@lists.infradead.org On Thu, Jun 09, 2022 at 10:39:22AM +0300, Tony Lindgren wrote: > * Arnd Bergmann [220608 18:18]: > > On Wed, Jun 8, 2022 at 4:27 PM Peter Zijlstra wrote: > > > > > > arch_cpu_idle() is a very simple idle interface and exposes only a > > > single idle state and is expected to not require RCU and not do any > > > tracing/instrumentation. > > > > > > As such, omap_sram_idle() is not a valid implementation. Replace it > > > with the simple (shallow) omap3_do_wfi() call. Leaving the more > > > complicated idle states for the cpuidle driver. > > Agreed it makes sense to limit deeper idle states to cpuidle. Hopefully > there is some informative splat for attempting to use arch_cpu_ide() > for deeper idle states :) The arch_cpu_idle() interface doesn't allow one to express a desire for deeper states. I'm not sure how anyone could even attempt this. But given what OMAP needs to go deeper, this would involve things that require RCU, combine that with the follow up patches that rip out all the trace_.*_rcuidle() hackery from the power and clock domain code, PROVE_RCU should scream if anybody were to attempt it. _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc 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 smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1686CC43334 for ; Thu, 9 Jun 2022 09:48:43 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id B65C340BF8; Thu, 9 Jun 2022 09:48:42 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id L8Pw9qZLXSxC; Thu, 9 Jun 2022 09:48:41 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp2.osuosl.org (Postfix) with ESMTPS id 3D11E4000B; Thu, 9 Jun 2022 09:48:41 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 04DB4C0032; Thu, 9 Jun 2022 09:48:41 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 5CC07C002D for ; Thu, 9 Jun 2022 09:48:39 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 2DE7840734 for ; Thu, 9 Jun 2022 09:48:39 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id A0oo5jDh621t for ; Thu, 9 Jun 2022 09:48:38 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by smtp2.osuosl.org (Postfix) with ESMTPS id CF0544000B for ; Thu, 9 Jun 2022 09:48:37 +0000 (UTC) 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=9jA4mchnYQoJ5XaXo73/qgoc6iaW5C3P1k7XaYKsS1U=; b=cB9XFjQVxWqfDyzeN0qaxTZuLD YLcvVXkDGRGNOtMLtEgH+zL1QwGa+jRQrKiDu6o+KwcqUIios781clMIKdQSQtEcXojjpXyjmvj46 euyjd4m+n/z+pXAWpiww5AHKVJISuO8dbwfn2kdK+vnbm4iQMh9u58KvobfYp6DKnGfTofnM78Yt0 Jz76LJDB6p5dvl91aPCez/Dj+sFAkswEne+HjI0PWGc0G7Uh6QasF9s0y9AlvQ8RjyVaUQ4ilXQ62 Z4qivKfe5pGVxrpCjV/g6X6ndctS6ICj5/6oYIabFd8D02kUsNuFDdK3DNDO+pifvTslSQOhwvIep NfI5oq7A==; Received: from dhcp-077-249-017-003.chello.nl ([77.249.17.3] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzElj-00DR5R-4H; Thu, 09 Jun 2022 09:47:59 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 100CA981287; Thu, 9 Jun 2022 11:47:58 +0200 (CEST) Date: Thu, 9 Jun 2022 11:47:57 +0200 From: Peter Zijlstra To: Tony Lindgren Subject: Re: [PATCH 33/36] cpuidle,omap3: Use WFI for omap3_pm_idle() Message-ID: References: <20220608142723.103523089@infradead.org> <20220608144518.010587032@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Cc: Juri Lelli , Rafael Wysocki , Benjamin Herrenschmidt , Linus Walleij , Ben Segall , Guo Ren , Pavel Machek , Alexander Gordeev , linux-arch , Vincent Guittot , Michael Ellerman , Huacai Chen , ACPI Devel Maling List , Andy Gross , Geert Uytterhoeven , NXP Linux Team , Catalin Marinas , xen-devel , Matt Turner , Michael Turquette , Sam Creasey , Petr Mladek , Linux PM list , Lai Jiangshan , Sascha Hauer , linux-um , Arnaldo Carvalho de Melo , Thomas Gleixner , linux-omap , Dietmar Eggemann , Richard Henderson , gregkh , Linux Kernel Mailing List , linux-perf-users@vger.kernel.org, Sergey Senozhatsky , Sven Schnelle , Jiri Olsa , Paul Mackerras , Mark Rutland , "open list:IA64 \(Itanium\) PLATFORM" , Dave Hansen , "open list:DRM DRIVER FOR QEMU'S CIRRUS DEVICE" , James Bottomley , Max Filippov , Thierry Reding , Xuerui Wang , quic_neeraju@quicinc.com, linux-s390 , vschneid@redhat.com, John Ogness , Yoshinori Sato , Linux-sh list , Will Deacon , Helge Deller , Daniel Lezcano , Jonathan Hunter , Mathieu Desnoyers , Frederic Weisbecker , Len Brown , "open list:TENSILICA XTENSA PORT \(xtensa\)" , Sascha Hauer , Vasily Gorbik , linux-arm-msm , alpha , linux-m68k , Stafford Horne , Linux ARM , Chris Zankel , Stephen Boyd , Dinh Nguyen , Daniel Bristot de Oliveira , Alexander Shishkin , lpieralisi@kernel.org, Rasmus Villemoes , Joel Fernandes , Fabio Estevam , Boris Ostrovsky , Kevin Hilman , linux-csky@vger.kernel.org, "open list:SYNOPSYS ARC ARCHITECTURE" , Mel Gorman , jacob.jun.pan@linux.intel.com, Arnd Bergmann , Hans Ulli Kroll , Vineet Gupta , linux-clk , Josh Triplett , Steven Rostedt , rcu@vger.kernel.org, Borislav Petkov , bcain@quicinc.com, Thomas Bogendoerfer , Parisc List , Sudeep Holla , Shawn Guo , David Miller , Rich Felker , Pv-drivers , amakhalov@vmware.com, Bjorn Andersson , "H. Peter Anvin" , sparclinux , "open list:QUALCOMM HEXAGON..." , linux-riscv , Anton Ivanov , Jonas Bonn , Yury Norov , Richard Weinberger , the arch/x86 maintainers , Russell King - ARM Linux , Ingo Molnar , Albert Ou , "Paul E. McKenney" , Heiko Carstens , Stefan Kristiansson , Openrisc , Paul Walmsley , "open list:TEGRA ARCHITECTURE SUPPORT" , Namhyung Kim , Andy Shevchenko , jpoimboe@kernel.org, Juergen Gross , Michal Simek , "open list:BROADCOM NVRAM DRIVER" , Palmer Dabbelt , Anup Patel , Ivan Kokshaysky , Johannes Berg , linuxppc-dev X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Thu, Jun 09, 2022 at 10:39:22AM +0300, Tony Lindgren wrote: > * Arnd Bergmann [220608 18:18]: > > On Wed, Jun 8, 2022 at 4:27 PM Peter Zijlstra wrote: > > > > > > arch_cpu_idle() is a very simple idle interface and exposes only a > > > single idle state and is expected to not require RCU and not do any > > > tracing/instrumentation. > > > > > > As such, omap_sram_idle() is not a valid implementation. Replace it > > > with the simple (shallow) omap3_do_wfi() call. Leaving the more > > > complicated idle states for the cpuidle driver. > > Agreed it makes sense to limit deeper idle states to cpuidle. Hopefully > there is some informative splat for attempting to use arch_cpu_ide() > for deeper idle states :) The arch_cpu_idle() interface doesn't allow one to express a desire for deeper states. I'm not sure how anyone could even attempt this. But given what OMAP needs to go deeper, this would involve things that require RCU, combine that with the follow up patches that rip out all the trace_.*_rcuidle() hackery from the power and clock domain code, PROVE_RCU should scream if anybody were to attempt it. _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization 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 mail.librecores.org (lists.librecores.org [88.198.125.70]) by smtp.lore.kernel.org (Postfix) with ESMTP id A876ECCA473 for ; Thu, 9 Jun 2022 10:42:03 +0000 (UTC) Received: from [172.31.1.100] (localhost.localdomain [127.0.0.1]) by mail.librecores.org (Postfix) with ESMTP id EF41724865; Thu, 9 Jun 2022 12:42:02 +0200 (CEST) Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by mail.librecores.org (Postfix) with ESMTPS id B805F2431D for ; Thu, 9 Jun 2022 11:48:35 +0200 (CEST) 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=9jA4mchnYQoJ5XaXo73/qgoc6iaW5C3P1k7XaYKsS1U=; b=cB9XFjQVxWqfDyzeN0qaxTZuLD YLcvVXkDGRGNOtMLtEgH+zL1QwGa+jRQrKiDu6o+KwcqUIios781clMIKdQSQtEcXojjpXyjmvj46 euyjd4m+n/z+pXAWpiww5AHKVJISuO8dbwfn2kdK+vnbm4iQMh9u58KvobfYp6DKnGfTofnM78Yt0 Jz76LJDB6p5dvl91aPCez/Dj+sFAkswEne+HjI0PWGc0G7Uh6QasF9s0y9AlvQ8RjyVaUQ4ilXQ62 Z4qivKfe5pGVxrpCjV/g6X6ndctS6ICj5/6oYIabFd8D02kUsNuFDdK3DNDO+pifvTslSQOhwvIep NfI5oq7A==; Received: from dhcp-077-249-017-003.chello.nl ([77.249.17.3] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzElj-00DR5R-4H; Thu, 09 Jun 2022 09:47:59 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 100CA981287; Thu, 9 Jun 2022 11:47:58 +0200 (CEST) Date: Thu, 9 Jun 2022 11:47:57 +0200 From: Peter Zijlstra To: Tony Lindgren Subject: Re: [PATCH 33/36] cpuidle,omap3: Use WFI for omap3_pm_idle() Message-ID: References: <20220608142723.103523089@infradead.org> <20220608144518.010587032@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Mailman-Approved-At: Thu, 09 Jun 2022 12:41:56 +0200 X-BeenThere: openrisc@lists.librecores.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: Discussion around the OpenRISC processor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Rafael Wysocki , Benjamin Herrenschmidt , Linus Walleij , Ben Segall , Guo Ren , Pavel Machek , Alexander Gordeev , srivatsa@csail.mit.edu, linux-arch , Vincent Guittot , Michael Ellerman , Huacai Chen , ACPI Devel Maling List , Andy Gross , NXP Linux Team , Catalin Marinas , xen-devel , Matt Turner , Christian Borntraeger , Michael Turquette , Sam Creasey , Petr Mladek , Linux PM list , Lai Jiangshan , Sascha Hauer , linux-um , Arnaldo Carvalho de Melo , Thomas Gleixner , linux-omap , Dietmar Eggemann , Richard Henderson , gregkh , Linux Kernel Mailing List , linux-perf-users@vger.kernel.org, Sergey Senozhatsky , Sven Schnelle , Jiri Olsa , Paul Mackerras , Mark Rutland , "open list:IA64 \(Itanium\) PLATFORM" , Dave Hansen , "open list:DRM DRIVER FOR QEMU'S CIRRUS DEVICE" , James Bottomley , Max Filippov , Thierry Reding , Xuerui Wang , quic_neeraju@quicinc.com, linux-s390 , vschneid@redhat.com, John Ogness , Yoshinori Sato , Linux-sh list , Will Deacon , Helge Deller , Daniel Lezcano , Jonathan Hunter , Mathieu Desnoyers , Frederic Weisbecker , Len Brown , "open list:TENSILICA XTENSA PORT \(xtensa\)" , Sascha Hauer , Vasily Gorbik , linux-arm-msm , alpha , linux-m68k , Linux ARM , Chris Zankel , Stephen Boyd , Dinh Nguyen , Daniel Bristot de Oliveira , Alexander Shishkin , lpieralisi@kernel.org, Rasmus Villemoes , Joel Fernandes , Fabio Estevam , Boris Ostrovsky , Kevin Hilman , linux-csky@vger.kernel.org, "open list:SYNOPSYS ARC ARCHITECTURE" , Mel Gorman , jacob.jun.pan@linux.intel.com, Arnd Bergmann , Hans Ulli Kroll , Vineet Gupta , linux-clk , Josh Triplett , Steven Rostedt , rcu@vger.kernel.org, Borislav Petkov , bcain@quicinc.com, Thomas Bogendoerfer , Parisc List , Sudeep Holla , Shawn Guo , David Miller , Rich Felker , Pv-drivers , amakhalov@vmware.com, Bjorn Andersson , "H. Peter Anvin" , sparclinux , "open list:QUALCOMM HEXAGON..." , linux-riscv , Anton Ivanov , Jonas Bonn , Yury Norov , Richard Weinberger , the arch/x86 maintainers , Russell King - ARM Linux , Ingo Molnar , Albert Ou , "Paul E. McKenney" , Heiko Carstens , Openrisc , Paul Walmsley , "open list:TEGRA ARCHITECTURE SUPPORT" , Namhyung Kim , Andy Shevchenko , jpoimboe@kernel.org, Juergen Gross , Michal Simek , "open list:BROADCOM NVRAM DRIVER" , Palmer Dabbelt , Anup Patel , Ivan Kokshaysky , Johannes Berg , linuxppc-dev Errors-To: openrisc-bounces@lists.librecores.org Sender: "OpenRISC" On Thu, Jun 09, 2022 at 10:39:22AM +0300, Tony Lindgren wrote: > * Arnd Bergmann [220608 18:18]: > > On Wed, Jun 8, 2022 at 4:27 PM Peter Zijlstra wrote: > > > > > > arch_cpu_idle() is a very simple idle interface and exposes only a > > > single idle state and is expected to not require RCU and not do any > > > tracing/instrumentation. > > > > > > As such, omap_sram_idle() is not a valid implementation. Replace it > > > with the simple (shallow) omap3_do_wfi() call. Leaving the more > > > complicated idle states for the cpuidle driver. > > Agreed it makes sense to limit deeper idle states to cpuidle. Hopefully > there is some informative splat for attempting to use arch_cpu_ide() > for deeper idle states :) The arch_cpu_idle() interface doesn't allow one to express a desire for deeper states. I'm not sure how anyone could even attempt this. But given what OMAP needs to go deeper, this would involve things that require RCU, combine that with the follow up patches that rip out all the trace_.*_rcuidle() hackery from the power and clock domain code, PROVE_RCU should scream if anybody were to attempt it. 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AE1F1CCA47C for ; Fri, 10 Jun 2022 15:33:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=8rdKF98AvqXlzrTu0Ei6BAalCKGMyZvzxy9uBbeJFo8=; b=SzL7huetTe1jvl mlzJ8XB3IusU0Hfouy4q5RQzQONh50QnA1lbkVZDoInelMkgkyzuqAEgRYKkA1Rj0xIdNGA2LiYUg x8zxQXCfQGsJOR/JHCpek0bJoD/ztdxcukA1BmzIy9mlHoRRVH0FLQ2FjOmfgu+yT8S5d2lwCstQi oDW3rt49fozYkwHu04q8IUl+LZVJkw8rEdeR5h/Na4FTxnCyyI5Z5cHxK2JXslLpKRCDL+zZFadIh gcsTQ32N5XrrBsl15MPrY0e0O13g3sjmNOMqmIj0rOft0UkHJNEJcGjrTG/8N4Rry8nrsIKKmcJNU E5lnsivXH0xH9qojGLbQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzgdR-008mbD-PM; Fri, 10 Jun 2022 15:33:17 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzElv-000m8u-Ck; Thu, 09 Jun 2022 09:48:11 +0000 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=9jA4mchnYQoJ5XaXo73/qgoc6iaW5C3P1k7XaYKsS1U=; b=cB9XFjQVxWqfDyzeN0qaxTZuLD YLcvVXkDGRGNOtMLtEgH+zL1QwGa+jRQrKiDu6o+KwcqUIios781clMIKdQSQtEcXojjpXyjmvj46 euyjd4m+n/z+pXAWpiww5AHKVJISuO8dbwfn2kdK+vnbm4iQMh9u58KvobfYp6DKnGfTofnM78Yt0 Jz76LJDB6p5dvl91aPCez/Dj+sFAkswEne+HjI0PWGc0G7Uh6QasF9s0y9AlvQ8RjyVaUQ4ilXQ62 Z4qivKfe5pGVxrpCjV/g6X6ndctS6ICj5/6oYIabFd8D02kUsNuFDdK3DNDO+pifvTslSQOhwvIep NfI5oq7A==; Received: from dhcp-077-249-017-003.chello.nl ([77.249.17.3] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzElj-00DR5R-4H; Thu, 09 Jun 2022 09:47:59 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 100CA981287; Thu, 9 Jun 2022 11:47:58 +0200 (CEST) Date: Thu, 9 Jun 2022 11:47:57 +0200 From: Peter Zijlstra To: Tony Lindgren Cc: Arnd Bergmann , Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King - ARM Linux , Hans Ulli Kroll , Linus Walleij , Shawn Guo , Sascha Hauer , Sascha Hauer , Fabio Estevam , NXP Linux Team , Kevin Hilman , Catalin Marinas , Will Deacon , Guo Ren , bcain@quicinc.com, Huacai Chen , Xuerui Wang , Geert Uytterhoeven , Sam Creasey , Michal Simek , Thomas Bogendoerfer , Dinh Nguyen , Jonas Bonn , Stefan Kristiansson , Stafford Horne , James Bottomley , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Paul Walmsley , Palmer Dabbelt , Albert Ou , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Yoshinori Sato , Rich Felker , David Miller , Richard Weinberger , Anton Ivanov , Johannes Berg , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , the arch/x86 maintainers , "H. Peter Anvin" , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Juergen Gross , srivatsa@csail.mit.edu, amakhalov@vmware.com, Pv-drivers , Boris Ostrovsky , Chris Zankel , Max Filippov , Rafael Wysocki , Len Brown , Pavel Machek , gregkh , Michael Turquette , Stephen Boyd , Daniel Lezcano , lpieralisi@kernel.org, Sudeep Holla , Andy Gross , Bjorn Andersson , Anup Patel , Thierry Reding , Jonathan Hunter , jacob.jun.pan@linux.intel.com, Yury Norov , Andy Shevchenko , Rasmus Villemoes , Steven Rostedt , Petr Mladek , Sergey Senozhatsky , John Ogness , "Paul E. McKenney" , Frederic Weisbecker , quic_neeraju@quicinc.com, Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , vschneid@redhat.com, jpoimboe@kernel.org, alpha , Linux Kernel Mailing List , "open list:SYNOPSYS ARC ARCHITECTURE" , Linux ARM , linux-omap , linux-csky@vger.kernel.org, "open list:QUALCOMM HEXAGON..." , "open list:IA64 (Itanium) PLATFORM" , linux-m68k , "open list:BROADCOM NVRAM DRIVER" , Openrisc , Parisc List , linuxppc-dev , linux-riscv , linux-s390 , Linux-sh list , sparclinux , linux-um , linux-perf-users@vger.kernel.org, "open list:DRM DRIVER FOR QEMU'S CIRRUS DEVICE" , xen-devel , "open list:TENSILICA XTENSA PORT (xtensa)" , ACPI Devel Maling List , Linux PM list , linux-clk , linux-arm-msm , "open list:TEGRA ARCHITECTURE SUPPORT" , linux-arch , rcu@vger.kernel.org Subject: Re: [PATCH 33/36] cpuidle,omap3: Use WFI for omap3_pm_idle() Message-ID: References: <20220608142723.103523089@infradead.org> <20220608144518.010587032@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Mailman-Approved-At: Fri, 10 Jun 2022 08:33:13 -0700 X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Thu, Jun 09, 2022 at 10:39:22AM +0300, Tony Lindgren wrote: > * Arnd Bergmann [220608 18:18]: > > On Wed, Jun 8, 2022 at 4:27 PM Peter Zijlstra wrote: > > > > > > arch_cpu_idle() is a very simple idle interface and exposes only a > > > single idle state and is expected to not require RCU and not do any > > > tracing/instrumentation. > > > > > > As such, omap_sram_idle() is not a valid implementation. Replace it > > > with the simple (shallow) omap3_do_wfi() call. Leaving the more > > > complicated idle states for the cpuidle driver. > > Agreed it makes sense to limit deeper idle states to cpuidle. Hopefully > there is some informative splat for attempting to use arch_cpu_ide() > for deeper idle states :) The arch_cpu_idle() interface doesn't allow one to express a desire for deeper states. I'm not sure how anyone could even attempt this. But given what OMAP needs to go deeper, this would involve things that require RCU, combine that with the follow up patches that rip out all the trace_.*_rcuidle() hackery from the power and clock domain code, PROVE_RCU should scream if anybody were to attempt it. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv 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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 12D7EC43334 for ; Fri, 10 Jun 2022 11:13:26 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4LKJH84FSgz3cYd for ; Fri, 10 Jun 2022 21:13:24 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=casper.20170209 header.b=cB9XFjQV; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=infradead.org (client-ip=2001:8b0:10b:1236::1; helo=casper.infradead.org; envelope-from=peterz@infradead.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=casper.20170209 header.b=cB9XFjQV; dkim-atps=neutral Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) (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 lists.ozlabs.org (Postfix) with ESMTPS id 4LJfRw0dhKz3bkC for ; Thu, 9 Jun 2022 19:48:43 +1000 (AEST) 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=9jA4mchnYQoJ5XaXo73/qgoc6iaW5C3P1k7XaYKsS1U=; b=cB9XFjQVxWqfDyzeN0qaxTZuLD YLcvVXkDGRGNOtMLtEgH+zL1QwGa+jRQrKiDu6o+KwcqUIios781clMIKdQSQtEcXojjpXyjmvj46 euyjd4m+n/z+pXAWpiww5AHKVJISuO8dbwfn2kdK+vnbm4iQMh9u58KvobfYp6DKnGfTofnM78Yt0 Jz76LJDB6p5dvl91aPCez/Dj+sFAkswEne+HjI0PWGc0G7Uh6QasF9s0y9AlvQ8RjyVaUQ4ilXQ62 Z4qivKfe5pGVxrpCjV/g6X6ndctS6ICj5/6oYIabFd8D02kUsNuFDdK3DNDO+pifvTslSQOhwvIep NfI5oq7A==; Received: from dhcp-077-249-017-003.chello.nl ([77.249.17.3] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzElj-00DR5R-4H; Thu, 09 Jun 2022 09:47:59 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 100CA981287; Thu, 9 Jun 2022 11:47:58 +0200 (CEST) Date: Thu, 9 Jun 2022 11:47:57 +0200 From: Peter Zijlstra To: Tony Lindgren Subject: Re: [PATCH 33/36] cpuidle,omap3: Use WFI for omap3_pm_idle() Message-ID: References: <20220608142723.103523089@infradead.org> <20220608144518.010587032@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Mailman-Approved-At: Fri, 10 Jun 2022 21:09:20 +1000 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Rafael Wysocki , Linus Walleij , Ben Segall , Guo Ren , Pavel Machek , Alexander Gordeev , srivatsa@csail.mit.edu, linux-arch , Vincent Guittot , Huacai Chen , ACPI Devel Maling List , Andy Gross , Geert Uytterhoeven , NXP Linux Team , Catalin Marinas , xen-devel , Matt Turner , Christian Borntraeger , Michael Turquette , Sam Creasey , Petr Mladek , Linux PM list , Lai Jiangshan , Sascha Hauer , linux-um , Arnaldo Carvalho de Melo , Thomas Gleixner , linux-omap , Dietmar Eggemann , Richard Henderson , gregkh , Linux Kernel Mailing List , linux-perf-users@vger.kernel.org, Sergey Senozhatsky , Sven Schnelle , Jiri Olsa , Paul Mackerras , Mark Rutland , "open list:IA64 \(Itanium\) PLATFORM" , Dave Hansen , "open list:DRM DRIVER FOR QEMU'S CIRRUS DEVICE" , James Bottomley , Max Filippov , Thierry Reding , Xuerui Wang , quic_neeraju@quicinc.com, linux-s390 , vschneid@redhat.com, John Ogn ess , Yoshinori Sato , Linux-sh list , Will Deacon , Helge Deller , Daniel Lezcano , Jonathan Hunter , Mathieu Desnoyers , Frederic Weisbecker , Len Brown , "open list:TENSILICA XTENSA PORT \(xtensa\)" , Sascha Hauer , Vasily Gorbik , linux-arm-msm , alpha , linux-m68k , Stafford Horne , Linux ARM , Chris Zankel , Stephen Boyd , Dinh Nguyen , Daniel Bristot de Oliveira , Alexander Shishkin , lpieralisi@kernel.org, Rasmus Villemoes , Joel Fernandes , Fabio Estevam , Boris Ostrovsky , Kevin Hilman , linux-csky@vger.kernel.org, "open list:SYNOPSYS ARC ARCHITECTURE" , Mel Gorman , jacob.jun.pan@linux.intel.com, Arnd Bergmann , Hans Ulli Kroll , Vineet Gupta , linux-clk , Josh Triplett , Steven Rostedt , rcu@vger.kernel.org, Borislav Petkov , bcain@quicinc.com, Thomas Bogendoerfer , Parisc List , Sudeep Holla , Shawn Guo , David Miller , Rich Felker , Pv-drivers , amakhalov@vmware.com, Bjorn Andersson , "H. Peter Anvin" , sparclinux , "open list:QUALCOMM HEXAGON..." , linux-riscv , Anton Ivanov , Jonas Bonn , Yury Norov , Richard Weinberger , the arch/x86 maintainers , Russell King - ARM Linux , Ingo Molnar , Albert Ou , "Paul E. McKenney" , Heiko Carstens , Stefan Kristiansson , Openrisc , Paul Walmsley , "open list:TEGRA ARCHITECTURE SUPPORT" , Namhyung Kim , Andy Shevchenko , jpoimboe@kernel.org, Juergen Gross , Michal Simek , "open list:BROADCOM NVRAM DRIVER" , Palmer Dabbelt , Anup Patel , Ivan Kokshaysky , Johannes Berg , linuxppc-dev Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Jun 09, 2022 at 10:39:22AM +0300, Tony Lindgren wrote: > * Arnd Bergmann [220608 18:18]: > > On Wed, Jun 8, 2022 at 4:27 PM Peter Zijlstra wrote: > > > > > > arch_cpu_idle() is a very simple idle interface and exposes only a > > > single idle state and is expected to not require RCU and not do any > > > tracing/instrumentation. > > > > > > As such, omap_sram_idle() is not a valid implementation. Replace it > > > with the simple (shallow) omap3_do_wfi() call. Leaving the more > > > complicated idle states for the cpuidle driver. > > Agreed it makes sense to limit deeper idle states to cpuidle. Hopefully > there is some informative splat for attempting to use arch_cpu_ide() > for deeper idle states :) The arch_cpu_idle() interface doesn't allow one to express a desire for deeper states. I'm not sure how anyone could even attempt this. But given what OMAP needs to go deeper, this would involve things that require RCU, combine that with the follow up patches that rip out all the trace_.*_rcuidle() hackery from the power and clock domain code, PROVE_RCU should scream if anybody were to attempt it. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Date: Thu, 09 Jun 2022 09:47:57 +0000 Subject: Re: [PATCH 33/36] cpuidle,omap3: Use WFI for omap3_pm_idle() Message-Id: List-Id: References: <20220608142723.103523089@infradead.org> <20220608144518.010587032@infradead.org> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tony Lindgren Cc: Arnd Bergmann , Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King - ARM Linux , Hans Ulli Kroll , Linus Walleij , Shawn Guo , Sascha Hauer , Sascha Hauer , Fabio Estevam , NXP Linux Team , Kevin Hilman , Catalin Marinas , Will Deacon , Guo Ren , bcain@quicinc.com, Huacai Chen , Xuerui Wang , Geert Uytterhoeven , Sam Creasey , Michal Simek , Thomas Bogendoerfer , Dinh Nguyen , Jonas Bonn , Stefan Kristiansson , Stafford Horne , James Bottomley , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Paul Walmsley , Palmer Dabbelt , Albert Ou , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Yoshinori Sato , Rich Felker , David Miller , Richard Weinberger , Anton Ivanov , Johannes Berg , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , the arch/x86 maintainers , "H. Peter Anvin" , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Juergen Gross , srivatsa@csail.mit.edu, amakhalov@vmware.com, Pv-drivers , Boris Ostrovsky , Chris Zankel , Max Filippov , Rafael Wysocki , Len Brown , Pavel Machek , gregkh , Michael Turquette , Stephen Boyd , Daniel Lezcano , lpieralisi@kernel.org, Sudeep Holla , Andy Gross , Bjorn Andersson , Anup Patel , Thierry Reding , Jonathan Hunter , jacob.jun.pan@linux.intel.com, Yury Norov , Andy Shevchenko , Rasmus Villemoes , Steven Rostedt , Petr Mladek , Sergey Senozhatsky , John Ogness , "Paul E. McKenney" , Frederic Weisbecker , quic_neeraju@quicinc.com, Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , vschneid@redhat.com, jpoimboe@kernel.org, alpha , Linux Kernel Mailing List , "open list:SYNOPSYS ARC ARCHITECTURE" , Linux ARM , linux-omap , linux-csky@vger.kernel.org, "open list:QUALCOMM HEXAGON..." , "open list:IA64 (Itanium) PLATFORM" , linux-m68k , "open list:BROADCOM NVRAM DRIVER" , Openrisc , Parisc List , linuxppc-dev , linux-riscv , linux-s390 , Linux-sh list , sparclinux , linux-um , linux-perf-users@vger.kernel.org, "open list:DRM DRIVER FOR QEMU'S CIRRUS DEVICE" , xen-devel , "open list:TENSILICA XTENSA PORT (xtensa)" , ACPI Devel Maling List , Linux PM list , linux-clk , linux-arm-msm , "open list:TEGRA ARCHITECTURE SUPPORT" , linux-arch , rcu@vger.kernel.org On Thu, Jun 09, 2022 at 10:39:22AM +0300, Tony Lindgren wrote: > * Arnd Bergmann [220608 18:18]: > > On Wed, Jun 8, 2022 at 4:27 PM Peter Zijlstra wrote: > > > > > > arch_cpu_idle() is a very simple idle interface and exposes only a > > > single idle state and is expected to not require RCU and not do any > > > tracing/instrumentation. > > > > > > As such, omap_sram_idle() is not a valid implementation. Replace it > > > with the simple (shallow) omap3_do_wfi() call. Leaving the more > > > complicated idle states for the cpuidle driver. > > Agreed it makes sense to limit deeper idle states to cpuidle. Hopefully > there is some informative splat for attempting to use arch_cpu_ide() > for deeper idle states :) The arch_cpu_idle() interface doesn't allow one to express a desire for deeper states. I'm not sure how anyone could even attempt this. But given what OMAP needs to go deeper, this would involve things that require RCU, combine that with the follow up patches that rip out all the trace_.*_rcuidle() hackery from the power and clock domain code, PROVE_RCU should scream if anybody were to attempt it. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH 33/36] cpuidle,omap3: Use WFI for omap3_pm_idle() Date: Thu, 9 Jun 2022 11:47:57 +0200 Message-ID: References: <20220608142723.103523089@infradead.org> <20220608144518.010587032@infradead.org> Mime-Version: 1.0 Return-path: 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=9jA4mchnYQoJ5XaXo73/qgoc6iaW5C3P1k7XaYKsS1U=; b=cB9XFjQVxWqfDyzeN0qaxTZuLD YLcvVXkDGRGNOtMLtEgH+zL1QwGa+jRQrKiDu6o+KwcqUIios781clMIKdQSQtEcXojjpXyjmvj46 euyjd4m+n/z+pXAWpiww5AHKVJISuO8dbwfn2kdK+vnbm4iQMh9u58KvobfYp6DKnGfTofnM78Yt0 Jz76LJDB6p5dvl91aPCez/Dj+sFAkswEne+HjI0PWGc0G7Uh6QasF9s0y9AlvQ8RjyVaUQ4ilXQ62 Z4qivKfe5pGVxrpCjV/g6X6ndctS6ICj5/6oYIabFd8D02kUsNuFDdK3DNDO+pifvTslSQOhwvIep NfI5oq7A==; Content-Disposition: inline In-Reply-To: List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tony Lindgren Cc: Arnd Bergmann , Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King - ARM Linux , Hans Ulli Kroll , Linus Walleij , Shawn Guo , Sascha Hauer , Sascha Hauer , Fabio Estevam , NXP Linux Team , Kevin Hilman , Catalin Marinas , Will Deacon , Guo Ren , bcain@quicinc.com, Huacai Chen , Xuerui Wang , Geert Uytterhoeven On Thu, Jun 09, 2022 at 10:39:22AM +0300, Tony Lindgren wrote: > * Arnd Bergmann [220608 18:18]: > > On Wed, Jun 8, 2022 at 4:27 PM Peter Zijlstra wrote: > > > > > > arch_cpu_idle() is a very simple idle interface and exposes only a > > > single idle state and is expected to not require RCU and not do any > > > tracing/instrumentation. > > > > > > As such, omap_sram_idle() is not a valid implementation. Replace it > > > with the simple (shallow) omap3_do_wfi() call. Leaving the more > > > complicated idle states for the cpuidle driver. > > Agreed it makes sense to limit deeper idle states to cpuidle. Hopefully > there is some informative splat for attempting to use arch_cpu_ide() > for deeper idle states :) The arch_cpu_idle() interface doesn't allow one to express a desire for deeper states. I'm not sure how anyone could even attempt this. But given what OMAP needs to go deeper, this would involve things that require RCU, combine that with the follow up patches that rip out all the trace_.*_rcuidle() hackery from the power and clock domain code, PROVE_RCU should scream if anybody were to attempt it.