Re: [PATCH 4/5] x86, acpi, cpu-hotplug: Enable MADT APIs to return disabled apicid.
From: Tejun Heo <tj@kernel.org>
Date: 2015-07-15 22:06:30
Also in:
linux-acpi, lkml
Hello, On Tue, Jul 07, 2015 at 05:30:24PM +0800, Tang Chen wrote:
From: Gu Zheng <redacted> All processors' apicids can be obtained by _MAT method or from MADT in ACPI. The current code ignores disabled processors and returns -ENODEV. After this patch, a new parameter will be added to MADT APIs so that caller is able to control if disabled processors are ignored.
This describes what the patch does but doesn't really explain what the patch is trying to achieve.
quoted hunk ↗ jump to hunk
@@ -282,8 +282,11 @@ static int acpi_processor_get_info(struct acpi_device *device) * Extra Processor objects may be enumerated on MP systems with * less than the max # of CPUs. They should be ignored _iff * they are physically not present. + * + * NOTE: Even if the processor has a cpuid, it may not present because
^ be
+ * cpuid <-> apicid mapping is persistent now.
Saying "now" is kinda weird as this is how the code is gonna be forever. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>