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authorLinus Torvalds <torvalds@linux-foundation.org>2009-03-26 16:05:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-03-26 16:05:01 -0700
commit831576fe40f4175e0767623cffa4aeb28157943a (patch)
treede54e628e5849d6cf201df4446d760d17f752326 /Documentation
parent21cdbc1378e8aa96e1ed4a606dce1a8e7daf7fdf (diff)
parent66fef08f7d5267b2312c4b48a6d2957d2d414105 (diff)
Merge branch 'sched-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (46 commits) sched: Add comments to find_busiest_group() function sched: Refactor the power savings balance code sched: Optimize the !power_savings_balance during fbg() sched: Create a helper function to calculate imbalance sched: Create helper to calculate small_imbalance in fbg() sched: Create a helper function to calculate sched_domain stats for fbg() sched: Define structure to store the sched_domain statistics for fbg() sched: Create a helper function to calculate sched_group stats for fbg() sched: Define structure to store the sched_group statistics for fbg() sched: Fix indentations in find_busiest_group() using gotos sched: Simple helper functions for find_busiest_group() sched: remove unused fields from struct rq sched: jiffies not printed per CPU sched: small optimisation of can_migrate_task() sched: fix typos in documentation sched: add avg_overlap decay x86, sched_clock(): mark variables read-mostly sched: optimize ttwu vs group scheduling sched: TIF_NEED_RESCHED -> need_reshed() cleanup sched: don't rebalance if attached on NULL domain ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/scheduler/00-INDEX2
-rw-r--r--Documentation/scheduler/sched-coding.txt126
2 files changed, 0 insertions, 128 deletions
diff --git a/Documentation/scheduler/00-INDEX b/Documentation/scheduler/00-INDEX
index aabcc3a089b..3c00c9c3219 100644
--- a/Documentation/scheduler/00-INDEX
+++ b/Documentation/scheduler/00-INDEX
@@ -2,8 +2,6 @@
- this file.
sched-arch.txt
- CPU Scheduler implementation hints for architecture specific code.
-sched-coding.txt
- - reference for various scheduler-related methods in the O(1) scheduler.
sched-design-CFS.txt
- goals, design and implementation of the Complete Fair Scheduler.
sched-domains.txt
diff --git a/Documentation/scheduler/sched-coding.txt b/Documentation/scheduler/sched-coding.txt
deleted file mode 100644
index cbd8db752ac..00000000000
--- 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.
-
-
-Locking
--------
-
-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)
-
-and
-
- 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.
-
-
-Values
-------
-
-MAX_PRIO
- 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).
-MAX_RT_PRIO
- The maximum real-time priority of the system. Valid RT priorities
- range from 0 to (MAX_RT_PRIO - 1).
-MAX_USER_RT_PRIO
- 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.
-MIN_TIMESLICE
-MAX_TIMESLICE
- Respectively, the minimum and maximum timeslices (quanta) of a process.
-
-Data
-----
-
-struct runqueue
- The main per-CPU runqueue data structure.
-struct task_struct
- The main per-process data structure.
-
-
-General Methods
----------------
-
-cpu_rq(cpu)
- Returns the runqueue of the specified cpu.
-this_rq()
- Returns the runqueue of the current cpu.
-task_rq(pid)
- Returns the runqueue which holds the specified pid.
-cpu_curr(cpu)
- Returns the task currently running on the given cpu.
-rt_task(pid)
- 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.
-set_current_state(state_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.
-yield()
- Place the current process at the end of the runqueue and call schedule.