Messages in this thread Patch in this message | | | From | "Zengtao (B)" <> | Subject | RE: [PATCH v2] cpu-topology: Skip the exist but not possible cpu nodes | Date | Tue, 14 Jan 2020 12:17:41 +0000 |
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> -----Original Message----- > From: Sudeep Holla [mailto:sudeep.holla@arm.com] > Sent: Tuesday, January 14, 2020 6:30 PM > To: Zengtao (B) > Cc: Linuxarm; Greg Kroah-Hartman; Rafael J. Wysocki; > linux-kernel@vger.kernel.org; Sudeep Holla > Subject: Re: [PATCH v2] cpu-topology: Skip the exist but not possible cpu > nodes > > On Tue, Jan 14, 2020 at 01:42:25AM +0000, Zengtao (B) wrote: > > Could you help to explain here? > > I understand there are two abnormal cases: > > 1. The cpu node exist in the device tree, but not a possible cpu. > > This case can be caught by of_cpu_node_to_id's return value. > > Yes if of_cpu_node_to_id returns -ENODEV, it means there's no logical > CPU associated with this DT node. > > > 2. The cpu node does not exist. This case can be caught by above logic. > Or > > do you think of_parse_phandle's return value is enough? > > Again yes, there's nothing extra needed. > > The only change you need is to consider -ENODEV while handling the > case(1) > Thanks very much for your explanation. So finally it turns into a very simple patch like this, more cleaner: +/* + * This function returns the logic cpu number of the node. + * There are basically three kinds of return values: + * (1) logic cpu number which is > 0. + * (2) -ENDEV when the node is valid one which can be found in the device tree + * but there is no possible cpu nodes to match, when the CONFIG_NR_CPUS is + * smaller than cpus node numbers in device tree, this will happen. It's + * suggested to just ignore this case. + * (3) -1 if the node does not exist in the device tree + */ static int __init get_cpu_for_node(struct device_node *node) { struct device_node *cpu_node; @@ -261,7 +271,8 @@ static int __init get_cpu_for_node(struct device_node *node) if (cpu >= 0) topology_parse_cpu_capacity(cpu_node, cpu); else - pr_crit("Unable to find CPU node for %pOF\n", cpu_node); + pr_info("CPU node for %pOF exist but the possible cpu range is :%*pbl\n", + cpu_node, cpumask_pr_args(cpu_possible_mask));
of_node_put(cpu_node); return cpu; @@ -286,9 +297,8 @@ static int __init parse_core(struct device_node *core, int package_id, cpu_topology[cpu].package_id = package_id; cpu_topology[cpu].core_id = core_id; cpu_topology[cpu].thread_id = i; - } else { - pr_err("%pOF: Can't get CPU for thread\n", - t); + } else if (cpu != -ENODEV) { + pr_err("%pOF: Can't get CPU for thread\n", t); of_node_put(t); return -EINVAL; } @@ -307,7 +317,7 @@ static int __init parse_core(struct device_node *core, int package_id,
cpu_topology[cpu].package_id = package_id; cpu_topology[cpu].core_id = core_id; - } else if (leaf) { + } else if (leaf && cpu != -ENODEV) { pr_err("%pOF: Can't get CPU for leaf core\n", core); return -EINVAL; } Any more suggestions?
Regards Zengtao
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