Commit a4da60b5 authored by Robert Love's avatar Robert Love Committed by Linus Torvalds

[PATCH] sched cleanup, comments, separate max prios

Attached patch is a resync of previous patches sent by Ingo and I.
Specifically:

	- create new MAX_USER_RT_PRIO value
	- separate uses of MAX_RT_PRIO vs MAX_USER_RT_PRIO
	- replace use of magic numbers by above
	- additional comments
parent 2dba8370
......@@ -28,8 +28,13 @@
* priority range is allocated to RT tasks, the 100-139
* range is for SCHED_OTHER tasks. Priority values are
* inverted: lower p->prio value means higher priority.
*
* MAX_USER_RT_PRIO allows the actual maximum RT priority
* to be separate from the value exported to user-space.
* NOTE: MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO.
*/
#define MAX_RT_PRIO 100
#define MAX_USER_RT_PRIO 100
#define MAX_PRIO (MAX_RT_PRIO + 40)
/*
......@@ -1071,7 +1076,7 @@ asmlinkage long sys_nice(int increment)
*/
int task_prio(task_t *p)
{
return p->prio - 100;
return p->prio - MAX_USER_RT_PRIO;
}
int task_nice(task_t *p)
......@@ -1137,7 +1142,7 @@ static int setscheduler(pid_t pid, int policy, struct sched_param *param)
* priority for SCHED_OTHER is 0.
*/
retval = -EINVAL;
if (lp.sched_priority < 0 || lp.sched_priority > 99)
if (lp.sched_priority < 0 || lp.sched_priority > MAX_USER_RT_PRIO-1)
goto out_unlock;
if ((policy == SCHED_OTHER) != (lp.sched_priority == 0))
goto out_unlock;
......@@ -1157,7 +1162,7 @@ static int setscheduler(pid_t pid, int policy, struct sched_param *param)
p->policy = policy;
p->rt_priority = lp.sched_priority;
if (policy != SCHED_OTHER)
p->prio = 99 - p->rt_priority;
p->prio = MAX_USER_RT_PRIO-1 - p->rt_priority;
else
p->prio = p->static_prio;
if (array)
......@@ -1237,7 +1242,7 @@ asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param *param)
/**
* sys_sched_setaffinity - set the cpu affinity of a process
* @pid: pid of the process
* @len: length of the bitmask pointed to by user_mask_ptr
* @len: length in bytes of the bitmask pointed to by user_mask_ptr
* @user_mask_ptr: user-space pointer to the new cpu mask
*/
asmlinkage int sys_sched_setaffinity(pid_t pid, unsigned int len,
......@@ -1289,7 +1294,7 @@ asmlinkage int sys_sched_setaffinity(pid_t pid, unsigned int len,
/**
* sys_sched_getaffinity - get the cpu affinity of a process
* @pid: pid of the process
* @len: length of the bitmask pointed to by user_mask_ptr
* @len: length in bytes of the bitmask pointed to by user_mask_ptr
* @user_mask_ptr: user-space pointer to hold the current cpu mask
*/
asmlinkage int sys_sched_getaffinity(pid_t pid, unsigned int len,
......@@ -1371,7 +1376,7 @@ asmlinkage long sys_sched_get_priority_max(int policy)
switch (policy) {
case SCHED_FIFO:
case SCHED_RR:
ret = 99;
ret = MAX_USER_RT_PRIO-1;
break;
case SCHED_OTHER:
ret = 0;
......@@ -1511,6 +1516,12 @@ void show_state(void)
read_unlock(&tasklist_lock);
}
/*
* double_rq_lock - safely lock two runqueues
*
* Note this does not disable interrupts like task_rq_lock,
* you need to do so manually before calling.
*/
static inline void double_rq_lock(runqueue_t *rq1, runqueue_t *rq2)
{
if (rq1 == rq2)
......@@ -1526,6 +1537,12 @@ static inline void double_rq_lock(runqueue_t *rq1, runqueue_t *rq2)
}
}
/*
* double_rq_unlock - safely unlock two runqueues
*
* Note this does not restore interrupts like task_rq_unlock,
* you need to do so manually after calling.
*/
static inline void double_rq_unlock(runqueue_t *rq1, runqueue_t *rq2)
{
spin_unlock(&rq1->lock);
......@@ -1675,7 +1692,7 @@ void set_cpus_allowed(task_t *p, unsigned long new_mask)
static int migration_thread(void * bind_cpu)
{
int cpu = cpu_logical_map((int) (long) bind_cpu);
struct sched_param param = { sched_priority: 99 };
struct sched_param param = { sched_priority: MAX_RT_PRIO-1 };
runqueue_t *rq;
int ret;
......
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