Revision 7f453c24b95a085fc7bd35d53b33abc4dc5a048b authored by Peter Zijlstra on 21 July 2009, 11:19:40 UTC, committed by Peter Zijlstra on 22 July 2009, 16:05:56 UTC
Anton noted that for inherited counters the counter-id as provided by PERF_SAMPLE_ID isn't mappable to the id found through PERF_RECORD_ID because each inherited counter gets its own id. His suggestion was to always return the parent counter id, since that is the primary counter id as exposed. However, these inherited counters have a unique identifier so that events like PERF_EVENT_PERIOD and PERF_EVENT_THROTTLE can be specific about which counter gets modified, which is important when trying to normalize the sample streams. This patch removes PERF_EVENT_PERIOD in favour of PERF_SAMPLE_PERIOD, which is more useful anyway, since changing periods became a lot more common than initially thought -- rendering PERF_EVENT_PERIOD the less useful solution (also, PERF_SAMPLE_PERIOD reports the more accurate value, since it reports the value used to trigger the overflow, whereas PERF_EVENT_PERIOD simply reports the requested period changed, which might only take effect on the next cycle). This still leaves us PERF_EVENT_THROTTLE to consider, but since that _should_ be a rare occurrence, and linking it to a primary id is the most useful bit to diagnose the problem, we introduce a PERF_SAMPLE_STREAM_ID, for those few cases where the full reconstruction is important. [Does change the ABI a little, but I see no other way out] Suggested-by: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1248095846.15751.8781.camel@twins>
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rtmutex_common.h
/*
* RT Mutexes: blocking mutual exclusion locks with PI support
*
* started by Ingo Molnar and Thomas Gleixner:
*
* Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
* Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
*
* This file contains the private data structure and API definitions.
*/
#ifndef __KERNEL_RTMUTEX_COMMON_H
#define __KERNEL_RTMUTEX_COMMON_H
#include <linux/rtmutex.h>
/*
* The rtmutex in kernel tester is independent of rtmutex debugging. We
* call schedule_rt_mutex_test() instead of schedule() for the tasks which
* belong to the tester. That way we can delay the wakeup path of those
* threads to provoke lock stealing and testing of complex boosting scenarios.
*/
#ifdef CONFIG_RT_MUTEX_TESTER
extern void schedule_rt_mutex_test(struct rt_mutex *lock);
#define schedule_rt_mutex(_lock) \
do { \
if (!(current->flags & PF_MUTEX_TESTER)) \
schedule(); \
else \
schedule_rt_mutex_test(_lock); \
} while (0)
#else
# define schedule_rt_mutex(_lock) schedule()
#endif
/*
* This is the control structure for tasks blocked on a rt_mutex,
* which is allocated on the kernel stack on of the blocked task.
*
* @list_entry: pi node to enqueue into the mutex waiters list
* @pi_list_entry: pi node to enqueue into the mutex owner waiters list
* @task: task reference to the blocked task
*/
struct rt_mutex_waiter {
struct plist_node list_entry;
struct plist_node pi_list_entry;
struct task_struct *task;
struct rt_mutex *lock;
#ifdef CONFIG_DEBUG_RT_MUTEXES
unsigned long ip;
struct pid *deadlock_task_pid;
struct rt_mutex *deadlock_lock;
#endif
};
/*
* Various helpers to access the waiters-plist:
*/
static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
{
return !plist_head_empty(&lock->wait_list);
}
static inline struct rt_mutex_waiter *
rt_mutex_top_waiter(struct rt_mutex *lock)
{
struct rt_mutex_waiter *w;
w = plist_first_entry(&lock->wait_list, struct rt_mutex_waiter,
list_entry);
BUG_ON(w->lock != lock);
return w;
}
static inline int task_has_pi_waiters(struct task_struct *p)
{
return !plist_head_empty(&p->pi_waiters);
}
static inline struct rt_mutex_waiter *
task_top_pi_waiter(struct task_struct *p)
{
return plist_first_entry(&p->pi_waiters, struct rt_mutex_waiter,
pi_list_entry);
}
/*
* lock->owner state tracking:
*/
#define RT_MUTEX_OWNER_PENDING 1UL
#define RT_MUTEX_HAS_WAITERS 2UL
#define RT_MUTEX_OWNER_MASKALL 3UL
static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
{
return (struct task_struct *)
((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
}
static inline struct task_struct *rt_mutex_real_owner(struct rt_mutex *lock)
{
return (struct task_struct *)
((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
}
static inline unsigned long rt_mutex_owner_pending(struct rt_mutex *lock)
{
return (unsigned long)lock->owner & RT_MUTEX_OWNER_PENDING;
}
/*
* PI-futex support (proxy locking functions, etc.):
*/
extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
struct task_struct *proxy_owner);
extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
struct task_struct *proxy_owner);
extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
struct rt_mutex_waiter *waiter,
struct task_struct *task,
int detect_deadlock);
extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
struct hrtimer_sleeper *to,
struct rt_mutex_waiter *waiter,
int detect_deadlock);
#ifdef CONFIG_DEBUG_RT_MUTEXES
# include "rtmutex-debug.h"
#else
# include "rtmutex.h"
#endif
#endif
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