hotplug / x86: Disable ARCH_CPU_PROBE_RELEASE on x86 (1cad5e9a) · Commits · 戴 / test

Commit enabled ARCH_CPU_PROBE_RELEASE on x86 in order to serialize CPU online/offline operations. Although it is the config option to enable CPU hotplug test interfaces, probe & release, it is also the option to enable cpu_hotplug_driver_lock() as well. Therefore, this option had to be enabled on x86 with dummy arch_cpu_probe() and arch_cpu_release(). Since then, lock_device_hotplug() was introduced to serialize CPU online/offline & hotplug operations. Therefore, this config option is no longer required for the serialization. This patch disables this config option on x86 and revert the changes made by commit . Signed-off-by:

Toshi Kani <toshi.kani@hp.com> Acked-by:

Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Signed-off-by:

Rafael J. Wysocki <rafael.j.wysocki@intel.com>

arch/x86/Kconfig

+0 −4

Original line number	Diff line number	Diff line
		@@ -254,10 +254,6 @@ config ARCH_HWEIGHT_CFLAGS
		default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
		default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64

		config ARCH_CPU_PROBE_RELEASE
		def_bool y
		depends on HOTPLUG_CPU

		config ARCH_SUPPORTS_UPROBES
		def_bool y

arch/x86/kernel/smpboot.c

+0 −21

Original line number	Diff line number	Diff line
		@@ -82,27 +82,6 @@
		/* State of each CPU */
		DEFINE_PER_CPU(int, cpu_state) = { 0 };

		#ifdef CONFIG_HOTPLUG_CPU
		/*
		* We need this for trampoline_base protection from concurrent accesses when
		* off- and onlining cores wildly.
		*/
		static DEFINE_MUTEX(x86_cpu_hotplug_driver_mutex);

		void cpu_hotplug_driver_lock(void)
		{
		mutex_lock(&x86_cpu_hotplug_driver_mutex);
		}

		void cpu_hotplug_driver_unlock(void)
		{
		mutex_unlock(&x86_cpu_hotplug_driver_mutex);
		}

		ssize_t arch_cpu_probe(const char *buf, size_t count) { return -1; }
		ssize_t arch_cpu_release(const char *buf, size_t count) { return -1; }
		#endif

		/* Number of siblings per CPU package */
		int smp_num_siblings = 1;
		EXPORT_SYMBOL(smp_num_siblings);

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