From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 56C3C1487D6; Wed, 17 Apr 2024 15:59:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713369589; cv=none; b=XZo+GTERHiv+TYEDWZRjH8P7AUTrK6h9oKxMzbxBv7kLzgsRW8XwmCCD1Whr8ANSidSpkY2hqe9Y1tO5Dj9SOxkR6B9q3ydTjtnQQqcIVwAMyy4rCIU5T5bvL+AdcP1oyCPNYPoIwQl/z/JJFaPotGGywSD0hFjEt1C7lrgRIbY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713369589; c=relaxed/simple; bh=gb50RbRpjXShl8LUS+BeL4GCX3tp8IZmzIWGi8zYb2o=; h=MIME-Version:References:In-Reply-To:From:Date:Message-ID:Subject: To:Cc:Content-Type; b=lkVRTcbiDJvnAryzbKwx3C3EY+H4M2v1whUeR2xPAI2uXS1bj0n0mNOMqSEbaF8qt4g7zyNpBeAgHEClVkZvrosp/2Wwk0vhRAzDZEqBX95HAEUHgBz4ctk8ubGmezsg8f17BXsiKlncxpKfdXmm2wdNvMAKsVyRK8igzLy64Uc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Q4l8Kfwj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Q4l8Kfwj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB142C3277B; Wed, 17 Apr 2024 15:59:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713369588; bh=gb50RbRpjXShl8LUS+BeL4GCX3tp8IZmzIWGi8zYb2o=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=Q4l8KfwjEoNkNho1LWmswicc037/5eLapUE1VdcnRjqsXf8kRf0HTOQ1vemvysLkq nxSlOVXxaTvzUU4WGz+NsOV7WikcvXX/KpoOIM/hYAGiTFHllUuWs6WKXcRYlu40ay Pkk5SexD4tDL5hFv+E+DFLx7ljNUmUVVS/S51IDNgzk9RWqyY0S/Wf610Lb2MEG6iv 8njR9H1fvEyqRoKeJ2VE+PTWKcb0r6CFLdn1+LVQLI7a0uGrk1PDKO3ETe3vKFTRF1 83XTe7sVhrm9hMtuQwJCgk+lSDiIbZetzmoiSU4xZuCDP3zQH03lwcjO61rG9K2w9M mp3ADjRQmANDQ== Received: by mail-ot1-f44.google.com with SMTP id 46e09a7af769-6eb7a4d64e8so1256222a34.0; Wed, 17 Apr 2024 08:59:48 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCWyHdSF7N5029EjotteOR0k3Sy2cqLurPRwuoc8gWfra1S5kvbEBtxsydnzeClnC8oCpLysP1VfxFV/M4h/VdGrG72bSF9G3/+4SwaRAVQg9rlV3fo1+KGD7jNBcytw3T6JFxDgDlbnWm+euRjeQjG+BZA0xWz6YdYTlHVOWTuN/z5z61C1ddvE75dHUxDz435ALAHBk8JMtk7EcU3VLg== X-Gm-Message-State: AOJu0YyguV55iiiRxV3jm4+MrmsU6aXlSzk2Jje4VC4DDob8/x0j1IIh bYUctcNA6vTVbJT9r+tmuDi1j758RK0hjDVNNSqG5FqBuc0qhhc8kA4CsS60eTfJTfJYehqmn5n hOBppvQulvHsRXEyWBx9xQkULK+4= X-Google-Smtp-Source: AGHT+IHAKhIHZsoDLSQEnmwhBQgjZcL36nblFqE1AGDjJdp3XQsw26v26OKEFMG9SrKLYedvqajXqzGXp9/n6TzlelM= X-Received: by 2002:a4a:9c56:0:b0:5aa:14ff:4128 with SMTP id c22-20020a4a9c56000000b005aa14ff4128mr25133ook.1.1713369588078; Wed, 17 Apr 2024 08:59:48 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20240417131909.7925-1-Jonathan.Cameron@huawei.com> <20240417131909.7925-7-Jonathan.Cameron@huawei.com> <22ace9b108ee488eb017f5b3e8facb8d@huawei.com> <20240417163842.0000415e@Huawei.com> In-Reply-To: <20240417163842.0000415e@Huawei.com> From: "Rafael J. Wysocki" Date: Wed, 17 Apr 2024 17:59:36 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v6 06/16] ACPI: processor: Register deferred CPUs from acpi_processor_get_info() To: Jonathan Cameron Cc: Salil Mehta , Thomas Gleixner , Peter Zijlstra , "linux-pm@vger.kernel.org" , "loongarch@lists.linux.dev" , "linux-acpi@vger.kernel.org" , "linux-arch@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "kvmarm@lists.linux.dev" , "x86@kernel.org" , Russell King , "Rafael J . Wysocki" , Miguel Luis , James Morse , Jean-Philippe Brucker , Catalin Marinas , Will Deacon , Ingo Molnar , Borislav Petkov , Dave Hansen , Linuxarm , "justin.he@arm.com" , "jianyong.wu@arm.com" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, Apr 17, 2024 at 5:38=E2=80=AFPM Jonathan Cameron wrote: > > On Wed, 17 Apr 2024 16:03:51 +0100 > Salil Mehta wrote: > > > > From: Jonathan Cameron > > > Sent: Wednesday, April 17, 2024 2:19 PM > > > > > > From: James Morse > > > > > > The arm64 specific arch_register_cpu() call may defer CPU registrati= on until > > > the ACPI interpreter is available and the _STA method can be evaluat= ed. > > > > > > If this occurs, then a second attempt is made in acpi_processor_get_= info(). > > > Note that the arm64 specific call has not yet been added so for now = this will > > > be called for the original hotplug case. > > > > > > For architectures that do not defer until the ACPI Processor driver = loads > > > (e.g. x86), for initially present CPUs there will already be a CPU d= evice. If > > > present do not try to register again. > > > > > > Systems can still be booted with 'acpi=3Doff', or not include an ACP= I > > > description at all as in these cases arch_register_cpu() will not ha= ve > > > deferred registration when first called. > > > > > > This moves the CPU register logic back to a subsys_initcall(), while= the > > > memory nodes will have been registered earlier. > > > Note this is where the call was prior to the cleanup series so there= should be > > > no side effects of moving it back again for this specific case. > > > > > > [PATCH 00/21] Initial cleanups for vCPU HP. > > > https://lore.kernel.org/all/ZVyz%2FVe5pPu8AWoA@shell.armlinux.org.uk= / > > > > > > e.g. 5b95f94c3b9f ("x86/topology: Switch over to GENERIC_CPU_DEVICES= ") > > > > > > Signed-off-by: James Morse > > > Reviewed-by: Gavin Shan > > > Tested-by: Miguel Luis > > > Tested-by: Vishnu Pajjuri > > > Tested-by: Jianyong Wu > > > Signed-off-by: Russell King (Oracle) > > > Co-developed-by: Jonathan Cameron > > > Signed-off-by: Joanthan Cameron > > > --- > > > v6: Squash the two paths for conventional CPU Hotplug and arm64 > > > vCPU HP. > > > v5: Update commit message to make it clear this is moving the > > > init back to where it was until very recently. > > > > > > No longer change the condition in the earlier registration point > > > as that will be handled by the arm64 registration routine > > > deferring until called again here. > > > --- > > > drivers/acpi/acpi_processor.c | 12 +++++++++++- > > > 1 file changed, 11 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_proce= ssor.c > > > index 7ecb13775d7f..0cac77961020 100644 > > > --- a/drivers/acpi/acpi_processor.c > > > +++ b/drivers/acpi/acpi_processor.c > > > @@ -356,8 +356,18 @@ static int acpi_processor_get_info(struct > > > acpi_device *device) > > > * > > > * NOTE: Even if the processor has a cpuid, it may not be presen= t > > > * because cpuid <-> apicid mapping is persistent now. > > > + * > > > + * Note this allows 3 flows, it is up to the arch_register_cpu() > > > + * call to reject any that are not supported on a given architec= ture. > > > + * A) CPU becomes present. > > > + * B) Previously invalid logical CPU ID (Same as becoming presen= t) > > > + * C) CPU already present and now being enabled (and wasn't > > > registered > > > + * early on an arch that doesn't defer to here) > > > */ > > > - if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id)) { > > > + if ((!invalid_logical_cpuid(pr->id) && cpu_present(pr->id) && > > > + !get_cpu_device(pr->id)) || > > > + invalid_logical_cpuid(pr->id) || > > > + !cpu_present(pr->id)) { > > > > > Hi Salil, > > Thanks for quick review! > > > Logic is clear but it is ugly. We should turn them into macro or inline= . > > You've found the 'ugly' in this approach vs keeping them separate. > > For this version I wanted to keep it clear that indeed this condition > is a complex mess of different things (and to let people compare > it easily with the two paths in v5 to convinced themselves this > is the same) > > It's also a little tricky to do, so will need some thought. > > I don't think a simple acpi_cpu_is_hotplug() condition is useful > as it just moves the complexity away from where a reader is looking > and it would only be used in this one case. > > It doesn't separate well into finer grained subconditions because > (C) is a messy case of the vCPU HP case and a not done > something else earlier. The disadvantage of only deferring for > arm64 and not other architectures. > > The best I can quickly come up with is something like this: > #define acpi_cpu_not_present(cpu) \ > (invalid_logical_cpuid(cpu) || !cpu_present(cpu)) > #define acpi_cpu_not_enabled(cpu) \ > (!invalid_logical_cpuid(cpu) || cpu_present(cpu)) > > if ((apci_cpu_not_enabled(pr->id) && !get_cpu_device(pr->id) || > acpi_cpu_not_present(pr->id)) > > Which would still need the same amount of documentation. The > code still isn't enough for me to immediately be able to see > what is going on. > > So maybe worth it... I'm not sure. Rafael, you get to keep this > fun, what would you prefer? I would use a static inline function returning bool to carry out these checks with comments explaining the different cases in which 'true' needs to be returned.