From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6152A4F3907; Thu, 17 Sep 2026 15:55:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660552; cv=none; b=VcPK05zlKlufUNO6J+AHyLTHZxE4kV/mvMuFq4Nvzbyhssh/7oBa2V6jcvUmtP6BHOSriV61vKQsyj676xu3wwaYL/7ByY+yWdaN1xe7y9kYQAgtI7JpEieLyCCzmwE3rNX/iy2rBQdP9UiJ6F/gVmRCBwONhUjV+RfU+tilorA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660552; c=relaxed/simple; bh=pu6OxP7sHRarHbFxvyGvIy2jdeMp3whl0Ww+2w+Yqk4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Z0HvXZ7LrtkAn7SOT/7IP3UXc3We82ZfXiMqUO8pmoEDdMKz0QJyTbDnwtJSKqSTQ4Z/dBIU1y9To9b/0nAV95fMpgmZjBBPH8+7UqO1mLikac19qaPcd9B+Y4IoYWt4IMYGHo1wVuOSALAheUbgoRV3+vmbGALHrjAYbLVmSGk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=FLgeeuFP; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="FLgeeuFP" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0819A1476; Thu, 17 Sep 2026 08:55:46 -0700 (PDT) Received: from [192.168.178.100] (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AA3B53F7B4; Thu, 17 Sep 2026 08:55:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789660549; bh=pu6OxP7sHRarHbFxvyGvIy2jdeMp3whl0Ww+2w+Yqk4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=FLgeeuFP12OYalq4ufgX2DESTMiE2Tp/2noR1ohfQnyzFdFKH/4YTsCF7BL2DiffS yxR8VV9A+e9avG4QOYLmvQPUlvbQisERazLgW5Sg35hefwU7+8YHgN/SAyL/A5/1+4 JIApr13pTg/Sab2zAkV1CufEkYRfeIXMoxFgX9VE= Message-ID: Date: Thu, 17 Sep 2026 17:55:44 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 1/2] arm64: topology: fix arch_freq_get_on_cpu() overflow above 4.19 GHz To: Peter Zijlstra , Oleg Keri Cc: Catalin Marinas , Will Deacon , Mark Rutland , Ingo Molnar , Juri Lelli , Vincent Guittot , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Sumit Gupta , Beata Michalska , Prasanna Kumar T S M , Sudeep Holla , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, Viresh Kumar , linux-pm@vger.kernel.org References: <20260917125112.2283-1-okerixx@gmail.com> <20260917125112.2283-2-okerixx@gmail.com> <20260917153224.GJ4121339@noisy.programming.kicks-ass.net> Content-Language: en-GB From: Dietmar Eggemann In-Reply-To: <20260917153224.GJ4121339@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 17.09.26 17:32, Peter Zijlstra wrote: > On Thu, Sep 17, 2026 at 02:51:11PM +0200, Oleg Keri wrote: [...] >> diff --git a/include/linux/topology.h b/include/linux/topology.h >> index 709a2dcf4c73..0a4ee12a98d5 100644 >> --- a/include/linux/topology.h >> +++ b/include/linux/topology.h >> @@ -351,4 +351,6 @@ static inline unsigned long topology_get_cpu_scale(int cpu) >> >> void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity); >> >> +#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT) > > This might not be a very good generic helper, since it relies on either > of the variables to be u64 for correctness. So moving it to a static inline function instead? static inline u64 cap_scale(u64 value, u64 scale) { return value * scale >> SCHED_CAPACITY_SHIFT; }