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 AAB0230DD11 for ; Mon, 22 Sep 2025 13:51:07 +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=1758549069; cv=none; b=Az2D1R4BqD1aCf7RiONKtIFqW3yiFqs01/b5VvjCA6bI7wXvLySj7BksjM+cBzIelP5qeNYDzDP8UiLfi1VqFRIDkE6acRGKz8+snu7RYpWmrYFr+hYZrFzP/1IihiHGw5ZRD239jkG2o9v/pl5PVQc+CX5adjh8p7Cqj3wIK9Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758549069; c=relaxed/simple; bh=CVN2rUVcu26MD0njIcUenwDoWFOs3Dq3unNWFMsapV4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OAojGctWahVCUdjsEnLpT518JttLminw1d6FjpgbiQsfzyk2xISgh+W1t6ckZwd8hKkCyx3V00otJEC2mHHYpZLI/RLN3qcp+bXlT3Prnu2Jtw00vD2aYt9SKmou+LQXZOM2gkQoHwW6QsAOjcINO5nI5iUKSMO/oLj1vusGsgE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com; spf=none smtp.mailfrom=foss.arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=foss.arm.com 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 E609B1424; Mon, 22 Sep 2025 06:50:58 -0700 (PDT) Received: from bogus (e133711.arm.com [10.1.196.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D9EA23F694; Mon, 22 Sep 2025 06:51:04 -0700 (PDT) Date: Mon, 22 Sep 2025 14:51:02 +0100 From: Sudeep Holla To: yunhui cui Cc: catalin.marinas@arm.com, will@kernel.org, gregkh@linuxfoundation.org, Sudeep Holla , rafael@kernel.org, dakr@kernel.org, beata.michalska@arm.com, ptsm@linux.microsoft.com, sumitg@nvidia.com, yangyicong@hisilicon.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [External] Re: [PATCH v3 1/1] arch_topology: move parse_acpi_topology() to common code Message-ID: <20250922-adventurous-pumpkin-booby-d4c95c@sudeepholla> References: <20250919085918.5442-1-cuiyunhui@bytedance.com> <20250919085918.5442-2-cuiyunhui@bytedance.com> <20250919-colossal-splendid-bettong-e5a0bd@sudeepholla> <20250922-buffalo-of-hypothetical-downpour-d2a47c@sudeepholla> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Mon, Sep 22, 2025 at 07:04:05PM +0800, yunhui cui wrote: > Hi Sudeep, > > On Mon, Sep 22, 2025 at 5:01 PM Sudeep Holla wrote: > > > > On Mon, Sep 22, 2025 at 10:18:57AM +0800, yunhui cui wrote: > > > Hi Sudeep, > > > > > > On Fri, Sep 19, 2025 at 10:05 PM Sudeep Holla wrote: > > > > [...] > > > > > > > > > > Just thinking if it makes sense keep acpi_cpu_is_threaded generic without > > > > the need for weak definition. > > > > > > > > Additional note: not sure why you haven't moved this under CONFIG_ARM64/RISCV as > > > > done with other code. > > > > > > > > bool __init acpi_cpu_is_threaded(int cpu) > > > > { > > > > int is_threaded = acpi_pptt_cpu_is_thread(cpu); > > > > > > > > /* > > > > * if the PPTT doesn't have thread information, check for architecture > > > > * specific fallback if available > > > > */ > > > > if (is_threaded < 0) > > > > is_threaded = arch_cpu_is_threaded(); > > > > > > > > return !!is_threaded; > > > > } > > > > > > > > Then you can just have the define in > > > > > > > > #define arch_cpu_is_threaded() (read_cpuid_mpidr() & MPIDR_MT_BITMASK) > > > > > > > > in arch/arm64/include/asm/topology.h > > > > > > > > and > > > > > > > > +#ifndef arch_cpu_is_threaded > > > > +#define arch_cpu_is_threaded (0) > > > > +#endif > > > > > > > > in include/linux/arch_topology.h > > > > > > > > Thoughts ? > > > > > > If placed in include/linux/arch_topology.h, there is a possibility > > > that "arch_cpu_is_threaded" will be redefined. > > > > > > > Why is that a problem ? We want arch to override the default definition > > if and when required. > > Because include/linux/topology.h first includes linux/arch_topology.h, > and then includes asm/topology.h, a warning will be generated during > compilation: > > In file included from ./include/linux/topology.h:37, > from ./include/linux/gfp.h:8, > from ./include/linux/xarray.h:16, > from ./include/linux/list_lru.h:14, > from ./include/linux/fs.h:14, > from kernel/events/core.c:11: > ./arch/arm64/include/asm/topology.h:39: warning: > "arch_cpu_is_threaded" redefined > 39 | #define arch_cpu_is_threaded() (read_cpuid_mpidr() & MPIDR_MT_BITMASK) > | > In file included from ./include/linux/topology.h:30: > ./include/linux/arch_topology.h:94: note: this is the location of the > previous definition > 94 | #define arch_cpu_is_threaded() (0) > > Unless #undef arch_cpu_is_threaded is used in arch/arm64/include/asm/topology.h, > The above way of #undef first should be fine. > So it's better to place > #ifndef arch_cpu_is_threaded > #define arch_cpu_is_threaded (0) > #endif > in include/asm-generic/topology.h. > I don't think asm-generic/topology.h is the right place and also you are again better on order of inclusion. -- Regards, Sudeep