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/*
* Definition of the scheduler plugin interface.
*
*/
#ifndef _LINUX_RT_PARAM_H_
#define _LINUX_RT_PARAM_H_
/* Litmus time type. */
typedef unsigned long long lt_t;
static inline int lt_after(lt_t a, lt_t b)
{
return ((long long) b) - ((long long) a) < 0;
}
#define lt_before(a, b) lt_after(b, a)
static inline int lt_after_eq(lt_t a, lt_t b)
{
return ((long long) a) - ((long long) b) >= 0;
}
#define lt_before_eq(a, b) lt_after_eq(b, a)
/* different types of clients */
typedef enum {
RT_CLASS_HARD,
RT_CLASS_SOFT,
RT_CLASS_BEST_EFFORT
} task_class_t;
struct rt_task {
lt_t exec_cost;
lt_t period;
unsigned int cpu;
task_class_t cls;
};
/* don't export internal data structures to user space (liblitmus) */
#ifdef __KERNEL__
struct rt_job {
/* Time instant the the job was or will be released. */
lt_t release;
/* What is the current deadline? */
lt_t deadline;
/* How much service has this job received so far?
*/
lt_t exec_time;
/* Which job is this. This is used to let user space
* specify which job to wait for, which is important if jobs
* overrun. If we just call sys_sleep_next_period() then we
* will unintentionally miss jobs after an overrun.
*
* Increase this sequence number when a job is released.
*/
unsigned int job_no;
/* when did this job start executing? */
lt_t exec_start;
};
/* RT task parameters for scheduling extensions
* These parameters are inherited during clone and therefore must
* be explicitly set up before the task set is launched.
*/
struct rt_param {
/* is the task sleeping? */
unsigned int flags:8;
/* Real-time marker: 1 iff it is a LITMUS real-time task.
*/
unsigned int is_realtime:1;
/* is a BE->RT or RT->BE transition pending? */
unsigned int transition_pending:1;
/* is this task under control of litmus?
*
* this is necessary because otherwise signal delivery code
* may try to wake up a task that is already queued in plugin
* data structures.
*
* bbb: I believe this flag is fundamentally flawed and should be
* taken out in the redesign.
*/
unsigned int litmus_controlled:1;
/* Did this task register any SRP controlled resource accesses?
* This, of course, should only ever be true under partitioning.
* However, this limitation is not currently enforced.
*/
unsigned int subject_to_srp:1;
/* if a BE->RT transition failed, then this field contains the error */
unsigned long transition_error;
/* user controlled parameters */
struct rt_task task_params;
/* timing parameters */
struct rt_job job_params;
/* task representing the current "inherited" task
* priority, assigned by inherit_priority and
* return priority in the scheduler plugins.
* could point to self if PI does not result in
* an increased task priority.
*/
struct task_struct* inh_task;
/* Don't just dereference this pointer in kernel space!
* It might very well point to junk or nothing at all.
* NULL indicates that the task has not requested any non-preemptable
* section support.
* Not inherited upon fork.
*/
short* np_flag;
/* For the FMLP under PSN-EDF, it is required to make the task
* non-preemptive from kernel space. In order not to interfere with
* user space, this counter indicates the kernel space np setting.
* kernel_np > 0 => task is non-preemptive
*/
unsigned int kernel_np;
/* This field can be used by plugins to store where the task
* is currently scheduled. It is the responsibility of the
* plugin to avoid race conditions.
*
* Used by GSN-EDF.
*/
int scheduled_on;
/* This field can be used by plugins to store where the task
* is currently linked. It is the responsibility of the plugin
* to avoid race conditions.
*
* Used by GSN-EDF.
*/
int linked_on;
/* Fields saved before BE->RT transition.
*/
int old_policy;
int old_prio;
};
/* Possible RT flags */
#define RT_F_RUNNING 0x00000000
#define RT_F_SLEEP 0x00000001
#define RT_F_EXIT_SEM 0x00000008
#endif
#endif
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