mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-26 01:00:58 +07:00
a9d9baa1e8
There are some callers in cpufreq hotplug notify path that the lowest function calls lock_cpu_hotplug(). The lock is already held during cpu_up() and cpu_down() calls when the notify calls are broadcast to registered clients. Ideally if possible, we could disable_preempt() at the highest caller and make sure we dont sleep in the path down in cpufreq->driver_target() calls but the calls are so intertwined and cumbersome to cleanup. Hence we consistently use lock_cpu_hotplug() and unlock_cpu_hotplug() in all places. - Removed export of cpucontrol semaphore and made it static. - removed explicit uses of up/down with lock_cpu_hotplug() so we can keep track of the the callers in same thread context and just keep refcounts without calling a down() that causes a deadlock. - Removed current_in_hotplug() uses - Removed PF_HOTPLUG_CPU in sched.h introduced for the current_in_hotplug() temporary workaround. Tested with insmod of cpufreq_stat.ko, and logical online/offline to make sure we dont have any hang situations. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Cc: Zwane Mwaikambo <zwane@linuxpower.ca> Cc: Shaohua Li <shaohua.li@intel.com> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
90 lines
2.5 KiB
C
90 lines
2.5 KiB
C
/*
|
|
* include/linux/cpu.h - generic cpu definition
|
|
*
|
|
* This is mainly for topological representation. We define the
|
|
* basic 'struct cpu' here, which can be embedded in per-arch
|
|
* definitions of processors.
|
|
*
|
|
* Basic handling of the devices is done in drivers/base/cpu.c
|
|
* and system devices are handled in drivers/base/sys.c.
|
|
*
|
|
* CPUs are exported via sysfs in the class/cpu/devices/
|
|
* directory.
|
|
*
|
|
* Per-cpu interfaces can be implemented using a struct device_interface.
|
|
* See the following for how to do this:
|
|
* - drivers/base/intf.c
|
|
* - Documentation/driver-model/interface.txt
|
|
*/
|
|
#ifndef _LINUX_CPU_H_
|
|
#define _LINUX_CPU_H_
|
|
|
|
#include <linux/sysdev.h>
|
|
#include <linux/node.h>
|
|
#include <linux/compiler.h>
|
|
#include <linux/cpumask.h>
|
|
#include <asm/semaphore.h>
|
|
|
|
struct cpu {
|
|
int node_id; /* The node which contains the CPU */
|
|
int no_control; /* Should the sysfs control file be created? */
|
|
struct sys_device sysdev;
|
|
};
|
|
|
|
extern int register_cpu(struct cpu *, int, struct node *);
|
|
extern struct sys_device *get_cpu_sysdev(int cpu);
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
extern void unregister_cpu(struct cpu *, struct node *);
|
|
#endif
|
|
struct notifier_block;
|
|
|
|
#ifdef CONFIG_SMP
|
|
/* Need to know about CPUs going up/down? */
|
|
extern int register_cpu_notifier(struct notifier_block *nb);
|
|
extern void unregister_cpu_notifier(struct notifier_block *nb);
|
|
extern int current_in_cpu_hotplug(void);
|
|
|
|
int cpu_up(unsigned int cpu);
|
|
|
|
#else
|
|
|
|
static inline int register_cpu_notifier(struct notifier_block *nb)
|
|
{
|
|
return 0;
|
|
}
|
|
static inline void unregister_cpu_notifier(struct notifier_block *nb)
|
|
{
|
|
}
|
|
static inline int current_in_cpu_hotplug(void)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_SMP */
|
|
extern struct sysdev_class cpu_sysdev_class;
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
/* Stop CPUs going up and down. */
|
|
extern void lock_cpu_hotplug(void);
|
|
extern void unlock_cpu_hotplug(void);
|
|
extern int lock_cpu_hotplug_interruptible(void);
|
|
#define hotcpu_notifier(fn, pri) { \
|
|
static struct notifier_block fn##_nb = \
|
|
{ .notifier_call = fn, .priority = pri }; \
|
|
register_cpu_notifier(&fn##_nb); \
|
|
}
|
|
int cpu_down(unsigned int cpu);
|
|
extern int __attribute__((weak)) smp_prepare_cpu(int cpu);
|
|
#define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
|
|
#else
|
|
#define lock_cpu_hotplug() do { } while (0)
|
|
#define unlock_cpu_hotplug() do { } while (0)
|
|
#define lock_cpu_hotplug_interruptible() 0
|
|
#define hotcpu_notifier(fn, pri)
|
|
|
|
/* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */
|
|
static inline int cpu_is_offline(int cpu) { return 0; }
|
|
#endif
|
|
|
|
#endif /* _LINUX_CPU_H_ */
|