[PATCH -v8 01/11] CPU hotplug: Provide a generic helper to disable/enable CPU hotplug
From: akpm@linux-foundation.org (Andrew Morton)
Date: 2013-05-09 22:01:24
Also in:
lkml, stable
On Tue, 7 May 2013 09:39:45 -0500 Robin Holt [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: "Srivatsa S. Bhat" <redacted> There are instances in the kernel where we would like to disable CPU hotplug (from sysfs) during some important operation. Today the freezer code depends on this and the code to do it was kinda tailor-made for that. Restructure the code and make it generic enough to be useful for other usecases too. ...--- a/include/linux/cpu.h +++ b/include/linux/cpu.h@@ -141,6 +141,8 @@ static inline void unregister_cpu_notifier(struct notifier_block *nb) } #endif +extern void cpu_hotplug_disable(void); +extern void cpu_hotplug_enable(void); int cpu_up(unsigned int cpu); void notify_cpu_starting(unsigned int cpu); extern void cpu_maps_update_begin(void);@@ -148,6 +150,7 @@ extern void cpu_maps_update_done(void); #else /* CONFIG_SMP */ +#define cpu_hotplug_disable() do { } while (0) #define cpu_notifier(fn, pri) do { (void)(fn); } while (0)
Breaks alpha allmodconfig because cpu_hotplug_disable() is absent from vmlinux. cpu_hotplug_disable() doesn't get compiled unless we've defined CONFIG_PM_SLEEP_SMP. I cannot begin to imagine what the logic is behind that! I'll stick this in there and see what happens.
--- a/include/linux/cpu.h~cpu-hotplug-provide-a-generic-helper-to-disable-enable-cpu-hotplug-fix
+++ a/include/linux/cpu.h@@ -141,8 +141,6 @@ static inline void unregister_cpu_notifi } #endif -extern void cpu_hotplug_disable(void); -extern void cpu_hotplug_enable(void); int cpu_up(unsigned int cpu); void notify_cpu_starting(unsigned int cpu); extern void cpu_maps_update_begin(void);
@@ -150,7 +148,6 @@ extern void cpu_maps_update_done(void); #else /* CONFIG_SMP */ -#define cpu_hotplug_disable() do { } while (0) #define cpu_notifier(fn, pri) do { (void)(fn); } while (0) static inline int register_cpu_notifier(struct notifier_block *nb)
@@ -171,6 +168,15 @@ static inline void cpu_maps_update_done( } #endif /* CONFIG_SMP */ + +#ifdef CONFIG_PM_SLEEP_SMP +extern void cpu_hotplug_enable(void); +extern void cpu_hotplug_disable(void); +#else +#define cpu_hotplug_enable() do { } while (0) +#define cpu_hotplug_disable() do { } while (0) +#endif + extern struct bus_type cpu_subsys; #ifdef CONFIG_HOTPLUG_CPU