From: Gavin Shan <gshan@redhat.com>
To: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
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,
linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev,
x86@kernel.org, linux-csky@vger.kernel.org,
linux-doc@vger.kernel.org, linux-ia64@vger.kernel.org,
linux-parisc@vger.kernel.org
Cc: Salil Mehta <salil.mehta@huawei.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
jianyong.wu@arm.com, justin.he@arm.com,
James Morse <james.morse@arm.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>
Subject: Re: [PATCH RFC 11/22] drivers: base: remove unnecessary call to register_cpu_under_node()
Date: Mon, 13 Nov 2023 14:04:32 +1000 [thread overview]
Message-ID: <955f2b95-76e4-4e68-830b-e6dd9f122dc1@redhat.com> (raw)
In-Reply-To: <E1r0JLa-00CTxY-Uv@rmk-PC.armlinux.org.uk>
On 11/7/23 20:30, Russell King (Oracle) wrote:
> Since "drivers: base: Move cpu_dev_init() after node_dev_init()", we
> can remove some redundant code.
>
> node_dev_init() will walk through the nodes calling register_one_node()
> on each. This will trickle down to __register_one_node() which walks
> all present CPUs, calling register_cpu_under_node() on each.
>
> register_cpu_under_node() will call get_cpu_device(cpu) for each, which
> will return NULL until the CPU is registered using register_cpu(). This
> now happens _after_ node_dev_init().
>
> Therefore, calling register_cpu_under_node() from __register_one_node()
> becomes a no-op, and can be removed.
>
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> ---
> drivers/base/node.c | 7 -------
> 1 file changed, 7 deletions(-)
>
__register_one_node() can be called in memory hot add path either. In that path,
a new NUMA node can be presented and becomes online. Does this become a problem
after the logic of associating CPU with newly added NUMA node?
Thanks,
Gavin
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> index 493d533f8375..4d5ac7cf8757 100644
> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -867,7 +867,6 @@ void register_memory_blocks_under_node(int nid, unsigned long start_pfn,
> int __register_one_node(int nid)
> {
> int error;
> - int cpu;
>
> node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
> if (!node_devices[nid])
> @@ -875,12 +874,6 @@ int __register_one_node(int nid)
>
> error = register_node(node_devices[nid], nid);
>
> - /* link cpu under this node */
> - for_each_present_cpu(cpu) {
> - if (cpu_to_node(cpu) == nid)
> - register_cpu_under_node(cpu, nid);
> - }
> -
> INIT_LIST_HEAD(&node_devices[nid]->access_list);
> node_init_caches(nid);
>
next prev parent reply other threads:[~2023-11-13 4:04 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-07 10:28 [PATCH RFC 00/22] Initial cleanups for vCPU hotplug Russell King (Oracle)
2023-11-07 10:29 ` [PATCH RFC 01/22] arch_topology: Make register_cpu_capacity_sysctl() tolerant to late CPUs Russell King
2023-11-13 0:04 ` Gavin Shan
2023-11-28 14:37 ` Jonathan Cameron
2023-11-28 15:41 ` Russell King (Oracle)
2023-11-07 10:29 ` [PATCH RFC 02/22] x86: intel_epb: Don't rely on link order Russell King
2023-11-13 0:03 ` Gavin Shan
2023-11-28 14:40 ` Jonathan Cameron
2023-11-28 15:42 ` Russell King (Oracle)
2023-11-07 10:29 ` [PATCH RFC 03/22] x86/topology: remove arch_*register_cpu() exports Russell King (Oracle)
2023-11-13 0:08 ` Gavin Shan
2023-11-28 14:42 ` Jonathan Cameron
2023-11-07 10:29 ` [PATCH RFC 04/22] Loongarch: " Russell King (Oracle)
2023-11-13 0:11 ` Gavin Shan
2023-11-28 14:43 ` Jonathan Cameron
2023-11-07 10:29 ` [PATCH RFC 05/22] ACPI: Move ACPI_HOTPLUG_CPU to be disabled on arm64 and riscv Russell King
2023-11-09 9:43 ` Shaoqin Huang
2023-11-13 0:29 ` Gavin Shan
2023-11-13 8:56 ` Russell King (Oracle)
2023-11-13 10:01 ` Gavin Shan
2023-11-28 14:46 ` Jonathan Cameron
2023-11-07 10:29 ` [PATCH RFC 06/22] drivers: base: Use present CPUs in GENERIC_CPU_DEVICES Russell King
2023-11-09 10:09 ` Shaoqin Huang
2023-11-09 10:29 ` Russell King (Oracle)
2023-11-09 10:59 ` Shaoqin Huang
2023-11-13 0:37 ` Gavin Shan
2023-11-07 10:29 ` [PATCH RFC 07/22] drivers: base: Allow parts of GENERIC_CPU_DEVICES to be overridden Russell King
2023-11-09 10:13 ` Shaoqin Huang
2023-11-13 0:42 ` Gavin Shan
2023-11-28 14:49 ` Jonathan Cameron
2023-11-07 10:29 ` [PATCH RFC 08/22] drivers: base: Implement weak arch_unregister_cpu() Russell King
2023-11-09 10:51 ` Shaoqin Huang
2023-11-13 0:45 ` Gavin Shan
2023-11-21 13:33 ` Russell King (Oracle)
2023-11-28 14:51 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 09/22] drivers: base: add arch_cpu_is_hotpluggable() Russell King (Oracle)
2023-11-10 3:27 ` Shaoqin Huang
2023-11-13 0:56 ` Gavin Shan
2023-11-28 14:53 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 10/22] drivers: base: Move cpu_dev_init() after node_dev_init() Russell King
2023-11-13 0:58 ` Gavin Shan
2023-11-13 8:00 ` Russell King (Oracle)
2023-11-21 13:27 ` Russell King (Oracle)
2023-11-28 13:55 ` Jonathan Cameron
2023-11-28 15:00 ` Jonathan Cameron
2023-11-30 12:17 ` Russell King (Oracle)
2023-11-07 10:30 ` [PATCH RFC 11/22] drivers: base: remove unnecessary call to register_cpu_under_node() Russell King (Oracle)
2023-11-13 4:04 ` Gavin Shan [this message]
2023-11-15 10:11 ` Russell King (Oracle)
2023-11-07 10:30 ` [PATCH RFC 12/22] drivers: base: Print a warning instead of panic() when register_cpu() fails Russell King
2023-11-10 3:35 ` Shaoqin Huang
2023-11-13 4:03 ` Gavin Shan
2023-11-28 15:05 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 13/22] arm64: setup: Switch over to GENERIC_CPU_DEVICES using arch_register_cpu() Russell King
2023-11-10 3:36 ` Shaoqin Huang
2023-11-13 4:07 ` Gavin Shan
2023-11-28 15:08 ` Jonathan Cameron
2023-11-28 15:12 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 14/22] arm64: convert to arch_cpu_is_hotpluggable() Russell King (Oracle)
2023-11-10 3:37 ` Shaoqin Huang
2023-11-13 4:09 ` Gavin Shan
2023-11-28 15:11 ` Jonathan Cameron
2023-11-30 12:09 ` Russell King (Oracle)
2023-11-07 10:30 ` [PATCH RFC 15/22] x86/topology: Switch over to GENERIC_CPU_DEVICES Russell King
2023-11-13 4:13 ` Gavin Shan
2023-11-28 15:16 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 16/22] x86/topology: use weak version of arch_unregister_cpu() Russell King (Oracle)
2023-11-13 4:16 ` Gavin Shan
2023-11-28 15:17 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 17/22] x86/topology: convert to use arch_cpu_is_hotpluggable() Russell King (Oracle)
2023-11-13 4:18 ` Gavin Shan
2023-11-28 15:18 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 18/22] LoongArch: Switch over to GENERIC_CPU_DEVICES Russell King
2023-11-13 4:20 ` Gavin Shan
2023-11-28 15:19 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 19/22] LoongArch: Use the __weak version of arch_unregister_cpu() Russell King
2023-11-07 10:31 ` [PATCH RFC 20/22] LoongArch: convert to use arch_cpu_is_hotpluggable() Russell King (Oracle)
2023-11-13 4:22 ` Gavin Shan
2023-11-28 15:20 ` Jonathan Cameron
2023-11-07 10:31 ` [PATCH RFC 21/22] riscv: Switch over to GENERIC_CPU_DEVICES Russell King
2023-11-07 17:48 ` Palmer Dabbelt
2023-11-13 4:23 ` Gavin Shan
2023-11-07 10:31 ` [PATCH RFC 22/22] riscv: convert to use arch_cpu_is_hotpluggable() Russell King (Oracle)
2023-11-07 17:48 ` Palmer Dabbelt
2023-11-13 4:24 ` Gavin Shan
2023-11-28 15:21 ` Jonathan Cameron
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