mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-24 05:04:00 +08:00
fb00aca474
Turn the pi-chains from plist to rb-tree, in the rt_mutex code, and provide a proper comparison function for -deadline and -priority tasks. This is done mainly because: - classical prio field of the plist is just an int, which might not be enough for representing a deadline; - manipulating such a list would become O(nr_deadline_tasks), which might be to much, as the number of -deadline task increases. Therefore, an rb-tree is used, and tasks are queued in it according to the following logic: - among two -priority (i.e., SCHED_BATCH/OTHER/RR/FIFO) tasks, the one with the higher (lower, actually!) prio wins; - among a -priority and a -deadline task, the latter always wins; - among two -deadline tasks, the one with the earliest deadline wins. Queueing and dequeueing functions are changed accordingly, for both the list of a task's pi-waiters and the list of tasks blocked on a pi-lock. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Dario Faggioli <raistlin@linux.it> Signed-off-by: Juri Lelli <juri.lelli@gmail.com> Signed-off-again-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1383831828-15501-10-git-send-email-juri.lelli@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
104 lines
2.9 KiB
C
104 lines
2.9 KiB
C
/*
|
|
* 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 public data structure and API definitions.
|
|
*/
|
|
|
|
#ifndef __LINUX_RT_MUTEX_H
|
|
#define __LINUX_RT_MUTEX_H
|
|
|
|
#include <linux/linkage.h>
|
|
#include <linux/rbtree.h>
|
|
#include <linux/spinlock_types.h>
|
|
|
|
extern int max_lock_depth; /* for sysctl */
|
|
|
|
/**
|
|
* The rt_mutex structure
|
|
*
|
|
* @wait_lock: spinlock to protect the structure
|
|
* @waiters: rbtree root to enqueue waiters in priority order
|
|
* @waiters_leftmost: top waiter
|
|
* @owner: the mutex owner
|
|
*/
|
|
struct rt_mutex {
|
|
raw_spinlock_t wait_lock;
|
|
struct rb_root waiters;
|
|
struct rb_node *waiters_leftmost;
|
|
struct task_struct *owner;
|
|
#ifdef CONFIG_DEBUG_RT_MUTEXES
|
|
int save_state;
|
|
const char *name, *file;
|
|
int line;
|
|
void *magic;
|
|
#endif
|
|
};
|
|
|
|
struct rt_mutex_waiter;
|
|
struct hrtimer_sleeper;
|
|
|
|
#ifdef CONFIG_DEBUG_RT_MUTEXES
|
|
extern int rt_mutex_debug_check_no_locks_freed(const void *from,
|
|
unsigned long len);
|
|
extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
|
|
#else
|
|
static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
|
|
unsigned long len)
|
|
{
|
|
return 0;
|
|
}
|
|
# define rt_mutex_debug_check_no_locks_held(task) do { } while (0)
|
|
#endif
|
|
|
|
#ifdef CONFIG_DEBUG_RT_MUTEXES
|
|
# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
|
|
, .name = #mutexname, .file = __FILE__, .line = __LINE__
|
|
# define rt_mutex_init(mutex) __rt_mutex_init(mutex, __func__)
|
|
extern void rt_mutex_debug_task_free(struct task_struct *tsk);
|
|
#else
|
|
# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
|
|
# define rt_mutex_init(mutex) __rt_mutex_init(mutex, NULL)
|
|
# define rt_mutex_debug_task_free(t) do { } while (0)
|
|
#endif
|
|
|
|
#define __RT_MUTEX_INITIALIZER(mutexname) \
|
|
{ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
|
|
, .waiters = RB_ROOT \
|
|
, .owner = NULL \
|
|
__DEBUG_RT_MUTEX_INITIALIZER(mutexname)}
|
|
|
|
#define DEFINE_RT_MUTEX(mutexname) \
|
|
struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
|
|
|
|
/**
|
|
* rt_mutex_is_locked - is the mutex locked
|
|
* @lock: the mutex to be queried
|
|
*
|
|
* Returns 1 if the mutex is locked, 0 if unlocked.
|
|
*/
|
|
static inline int rt_mutex_is_locked(struct rt_mutex *lock)
|
|
{
|
|
return lock->owner != NULL;
|
|
}
|
|
|
|
extern void __rt_mutex_init(struct rt_mutex *lock, const char *name);
|
|
extern void rt_mutex_destroy(struct rt_mutex *lock);
|
|
|
|
extern void rt_mutex_lock(struct rt_mutex *lock);
|
|
extern int rt_mutex_lock_interruptible(struct rt_mutex *lock,
|
|
int detect_deadlock);
|
|
extern int rt_mutex_timed_lock(struct rt_mutex *lock,
|
|
struct hrtimer_sleeper *timeout,
|
|
int detect_deadlock);
|
|
|
|
extern int rt_mutex_trylock(struct rt_mutex *lock);
|
|
|
|
extern void rt_mutex_unlock(struct rt_mutex *lock);
|
|
|
|
#endif
|