path: root/Documentation/scheduler
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authorWang Chen <wangchen@cn.fujitsu.com>2009-03-02 05:55:14 (GMT)
committerIngo Molnar <mingo@elte.hu>2009-03-02 11:02:52 (GMT)
commit72fd455ba54b5a02b9c74221b9ded8b1845b464a (patch)
tree206f04500c9dffeede7a275228ef08cec9d43083 /Documentation/scheduler
parent5512b3ece0cbb5024b83099963222700aa45f59e (diff)
sched, documentation: remove old O(1) scheduler document
Since we don't have O(1) scheduler implementation anymore, remove the legacy doc. Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation/scheduler')
2 files changed, 0 insertions, 128 deletions
diff --git a/Documentation/scheduler/00-INDEX b/Documentation/scheduler/00-INDEX
index aabcc3a..3c00c9c 100644
--- a/Documentation/scheduler/00-INDEX
+++ b/Documentation/scheduler/00-INDEX
@@ -2,8 +2,6 @@
- this file.
- CPU Scheduler implementation hints for architecture specific code.
- - reference for various scheduler-related methods in the O(1) scheduler.
- goals, design and implementation of the Complete Fair Scheduler.
diff --git a/Documentation/scheduler/sched-coding.txt b/Documentation/scheduler/sched-coding.txt
deleted file mode 100644
index cbd8db7..0000000
--- a/Documentation/scheduler/sched-coding.txt
+++ /dev/null
@@ -1,126 +0,0 @@
- Reference for various scheduler-related methods in the O(1) scheduler
- Robert Love <rml@tech9.net>, MontaVista Software
-Note most of these methods are local to kernel/sched.c - this is by design.
-The scheduler is meant to be self-contained and abstracted away. This document
-is primarily for understanding the scheduler, not interfacing to it. Some of
-the discussed interfaces, however, are general process/scheduling methods.
-They are typically defined in include/linux/sched.h.
-Main Scheduling Methods
-void load_balance(runqueue_t *this_rq, int idle)
- Attempts to pull tasks from one cpu to another to balance cpu usage,
- if needed. This method is called explicitly if the runqueues are
- imbalanced or periodically by the timer tick. Prior to calling,
- the current runqueue must be locked and interrupts disabled.
-void schedule()
- The main scheduling function. Upon return, the highest priority
- process will be active.
-Each runqueue has its own lock, rq->lock. When multiple runqueues need
-to be locked, lock acquires must be ordered by ascending &runqueue value.
-A specific runqueue is locked via
- task_rq_lock(task_t pid, unsigned long *flags)
-which disables preemption, disables interrupts, and locks the runqueue pid is
-running on. Likewise,
- task_rq_unlock(task_t pid, unsigned long *flags)
-unlocks the runqueue pid is running on, restores interrupts to their previous
-state, and reenables preemption.
-The routines
- double_rq_lock(runqueue_t *rq1, runqueue_t *rq2)
- double_rq_unlock(runqueue_t *rq1, runqueue_t *rq2)
-safely lock and unlock, respectively, the two specified runqueues. They do
-not, however, disable and restore interrupts. Users are required to do so
-manually before and after calls.
- The maximum priority of the system, stored in the task as task->prio.
- Lower priorities are higher. Normal (non-RT) priorities range from
- MAX_RT_PRIO to (MAX_PRIO - 1).
- The maximum real-time priority of the system. Valid RT priorities
- range from 0 to (MAX_RT_PRIO - 1).
- The maximum real-time priority that is exported to user-space. Should
- always be equal to or less than MAX_RT_PRIO. Setting it less allows
- kernel threads to have higher priorities than any user-space task.
- Respectively, the minimum and maximum timeslices (quanta) of a process.
-struct runqueue
- The main per-CPU runqueue data structure.
-struct task_struct
- The main per-process data structure.
-General Methods
- Returns the runqueue of the specified cpu.
- Returns the runqueue of the current cpu.
- Returns the runqueue which holds the specified pid.
- Returns the task currently running on the given cpu.
- Returns true if pid is real-time, false if not.
-Process Control Methods
-void set_user_nice(task_t *p, long nice)
- Sets the "nice" value of task p to the given value.
-int setscheduler(pid_t pid, int policy, struct sched_param *param)
- Sets the scheduling policy and parameters for the given pid.
-int set_cpus_allowed(task_t *p, unsigned long new_mask)
- Sets a given task's CPU affinity and migrates it to a proper cpu.
- Callers must have a valid reference to the task and assure the
- task not exit prematurely. No locks can be held during the call.
-set_task_state(tsk, state_value)
- Sets the given task's state to the given value.
- Sets the current task's state to the given value.
-void set_tsk_need_resched(struct task_struct *tsk)
- Sets need_resched in the given task.
-void clear_tsk_need_resched(struct task_struct *tsk)
- Clears need_resched in the given task.
-void set_need_resched()
- Sets need_resched in the current task.
-void clear_need_resched()
- Clears need_resched in the current task.
-int need_resched()
- Returns true if need_resched is set in the current task, false
- otherwise.
- Place the current process at the end of the runqueue and call schedule.

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