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=-7.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 28BEDC47089 for ; Thu, 27 May 2021 11:55:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0394E6103E for ; Thu, 27 May 2021 11:55:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234361AbhE0L5M (ORCPT ); Thu, 27 May 2021 07:57:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:49754 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233683AbhE0L5J (ORCPT ); Thu, 27 May 2021 07:57:09 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4E6AD6103E; Thu, 27 May 2021 11:55:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622116536; bh=pHiGUksg5cPGxFG52DohbH7Ek7e5+uWKvRCAt78JGuk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=l+QbYfvAoCsAgbrebJg9SYxXHOdc8rxHRTVP325dkWl2AsEgjAKWDTDLkJkpwW1F6 a2zW/EZ1oYLp+z6XTTtH+oiFNIGL3HSRDvRes24O6klHUIeFUGk//BqZvVOO8lRs+p w+KXjBpIubYEtVdQIZP//s2yg7SoGuGHuoJY4xPWR5/C0vqKXl16C+5k7snFn3wwZV mGl36KkoX894qY51Go560soaXldvQ1NV7tk4UP+15/ooNArfMZjaFpqEONTJQ6gA9z DZe5Gy9DSBl9QkeWkL013nEO30BkTlaDHXoUZgPaDRB0VRuz3IyGdHOwQbR6Pjf+Rh nXEvY5tq7HaeQ== Date: Thu, 27 May 2021 12:55:30 +0100 From: Will Deacon To: Xin Hao Cc: fweisbec@gmail.com, john.stultz@linaro.org, kernel-team@android.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, lorenzo@google.com, maz@kernel.org, mika.penttila@nextfour.com, sboyd@kernel.org, tglx@linutronix.de Subject: Re: [PATCH v2 2/5] tick/broadcast: Split __tick_broadcast_oneshot_control() into a helper Message-ID: <20210527115530.GC22019@willie-the-truck> References: <20210524221818.15850-3-will@kernel.org> <20210527082219.GA21311@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 27, 2021 at 07:35:03PM +0800, Xin Hao wrote: > > 在 2021/5/27 下午4:22, Will Deacon 写道: > > On Thu, May 27, 2021 at 03:23:06PM +0800, Xin Hao wrote: > > >      I  had backport you  tick/broadcast: Prefer per-cpu relatives patches, > > > > > > but i did not get the true result,  the Wakeup Devices are all null, why? > > Probably because you don't have any suitable per-cpu timers to act as a > > wakeup. Do you have a per-cpu timer registered with CLOCK_EVT_FEAT_PERCPU > > Yes, you are right, but i want to know why the timer do not support  > CLOCK_EVT_FEAT_PERCPU. I suspect there may be drivers with the feature missing simply because it wasn't really used for much until now (I think it just prevented use for broadcast). However, before adding that to a timer, you do need to make sure that it really is banked per-cpu (or at least handles racing accesses) as well as having the per-cpu irq. Will