From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E8BE813A3FF; Mon, 8 Jul 2024 13:53:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720446795; cv=none; b=fmMNrWuKzB4vJOMK585U37yM9IvO0qeAF+Lw7uixp+wSRI/zsPL497PzSI0CvQ7oKvOdcEcy7qF/PoMzPbrsjJDEZVVxeMJZrrLuoOJAJGDbEbxhgrYhwwSZCEQbH92H0i96h8IS4okFbfOugsqVYaMEvkbdgjjjx0+swuk8tQY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720446795; c=relaxed/simple; bh=/r+/nMzPahn0eESG2XANrb9OH0ViDm6C4ibSsbg1d6A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gTZtxyQ6G5Gcx4prFln0oq10IyqUNQw0olsZ+xeEr0TeW8ueJ7X28BDfVCgRmIZTuCh9pnRsS2/RSVSvrSgnfANssctlv0+Ccq4eXYd102TnJPAVjQogcYbFjalYVInz0i+QkZCyfledlWSWLngXz7fneiOxGFMxXcJqIZgDz8Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=idMvzb3t; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=M13IblR0; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="idMvzb3t"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="M13IblR0" Date: Mon, 8 Jul 2024 15:53:10 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1720446791; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=3Msuqgjwb5He6YYwNRjzMabQUnm6Wy6XzGH5sueeY8Q=; b=idMvzb3tG0e27yENCyIPgOaUlpXrpKSEMlndewY3UuHO9wv93LN1IkvziRk/3yQGls+NSs IalS3y3r6+317icTSIpFhdcDtnpjEMoeVn4MrcNenLwPq0xMQhlaF92atj+HV95lSLhMRu 8hIrHYBEth7PpA2EDYnnATFUeE4Cwqri2yRvD/GQycfnzzgSPM2aNAFP2qhQPirChEe5Dj KZ3MrpHQA+Pj+Xlw6cCKd+JERxP7jDPP+yZyibwjKG7sNs+5RInafnnd3g2wh4HPNoNbUc ekA2jXzXG70NIuheP5ot0ZzGxhRG2YDYa91GdfMrFXrFk3+bnk6i9tBhUCv1Cw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1720446791; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=3Msuqgjwb5He6YYwNRjzMabQUnm6Wy6XzGH5sueeY8Q=; b=M13IblR0AfHP6xSVuJw+Ty5KFZaCF8douxAxyPoEdDQhvo1kTOoyk5738csvtak+08cDmb TwDqqBYx9O73bEAg== From: Sebastian Andrzej Siewior To: Ulf Hansson Cc: "Rafael J . Wysocki" , Sudeep Holla , linux-pm@vger.kernel.org, Lorenzo Pieralisi , Nikunj Kela , Prasad Sodagudi , Maulik Shah , Daniel Lezcano , Krzysztof Kozlowski , linux-rt-users@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 0/7] pmdomain/cpuidle-psci: Support s2idle/s2ram on PREEMPT_RT Message-ID: <20240708135310.3VRFnmk1@linutronix.de> References: <20240527142557.321610-1-ulf.hansson@linaro.org> Precedence: bulk X-Mailing-List: linux-rt-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240527142557.321610-1-ulf.hansson@linaro.org> On 2024-05-27 16:25:50 [+0200], Ulf Hansson wrote: > Updates in v2: > - Rebased and fixed a small issue in genpd, see patch3. > - Re-tested on v6.9-rt5 (PREEMPT_RT enabled) > - Re-tested on v6.10-rc1 (for regressions, PREEMPT_RT disabled) > > The hierarchical PM domain topology and the corresponding domain-idle-states > are currently disabled on a PREEMPT_RT based configuration. The main reason is > because spinlocks are turned into sleepable locks on PREEMPT_RT, which means > genpd and runtime PM can't be use in the atomic idle-path when > selecting/entering an idle-state. > > For s2idle/s2ram this is an unnecessary limitation that this series intends to > address. Note that, the support for cpuhotplug is left to future improvements. > More information about this are available in the commit messages. I looked at it and it seems limited to pmdomain/core.c, also I don't know if there is a ->set_performance_state callback set since the one I checked have mutex_t locking ;) So if this is needed, then be it. s2ram wouldn't be used in "production" but in "safe state" so I wouldn't worry too much about latency spikes. Not sure what it means for the other modes. I am not to worried for now, please don't let spread more than needed ;) > Kind regards > Ulf Hansson Sebastian