linux/kernel/sched_rt.c, branch v2.6.26

sched: rt: dont stop the period timer when there are tasks wanting to run

2008-06-20T09:00:19Z

So if the group ever gets throttled, it will never wake up again. Reported-by: "Daniel K." Signed-off-by: Peter Zijlstra Tested-by: Daniel K. Signed-off-by: Ingo Molnar

sched: rt-group: fix RR buglet

2008-06-19T07:06:59Z

In tick_task_rt() we first call update_curr_rt() which can dequeue a runqueue due to it running out of runtime, and then we try to requeue it, of it also having exhausted its RR quota. Obviously requeueing something that is no longer on the runqueue will not have the expected result. Signed-off-by: Peter Zijlstra Tested-by: Daniel K. Signed-off-by: Ingo Molnar

sched: rt-group: heirarchy aware throttle

2008-06-19T07:06:57Z

The bandwidth throttle code dequeues a group when it runs out of quota, and re-queues it once the period rolls over and the quota gets refreshed. Sadly it failed to take the hierarchy into consideration. Share more of the enqueue/dequeue code with regular task opterations. Also, some operations like sched_setscheduler() can dequeue/enqueue tasks that are in throttled runqueues, we should not inadvertly re-enqueue empty runqueues so check for that. Signed-off-by: Peter Zijlstra Tested-by: Daniel K. Signed-off-by: Ingo Molnar

revert ("sched: fair-group: SMP-nice for group scheduling")

2008-05-29T09:28:57Z

Yanmin Zhang reported: Comparing with 2.6.25, volanoMark has big regression with kernel 2.6.26-rc1. It's about 50% on my 8-core stoakley, 16-core tigerton, and Itanium Montecito. With bisect, I located the following patch: | 18d95a2832c1392a2d63227a7a6d433cb9f2037e is first bad commit | commit 18d95a2832c1392a2d63227a7a6d433cb9f2037e | Author: Peter Zijlstra | Date: Sat Apr 19 19:45:00 2008 +0200 | | sched: fair-group: SMP-nice for group scheduling Revert it so that we get v2.6.25 behavior. Bisected-by: Yanmin Zhang Signed-off-by: Ingo Molnar

sched: fix RT task-wakeup logic

2008-05-05T21:56:18Z

Dmitry Adamushko pointed out a logic error in task_wake_up_rt() where we will always evaluate to "true". You can find the thread here: http://lkml.org/lkml/2008/4/22/296 In reality, we only want to try to push tasks away when a wake up request is not going to preempt the current task. So lets fix it. Note: We introduce test_tsk_need_resched() instead of open-coding the flag check so that the merge-conflict with -rt should help remind us that we may need to support NEEDS_RESCHED_DELAYED in the future, too. Signed-off-by: Gregory Haskins CC: Dmitry Adamushko CC: Steven Rostedt Signed-off-by: Ingo Molnar

sched: make rt_sched_class, idle_sched_class static

2008-05-05T21:56:17Z

The C files are included directly in sched.c, so they are effectively static. Signed-off-by: Harvey Harrison Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar

sched: rt-group: optimize dequeue_rt_stack

2008-04-19T17:45:00Z

Now that the group hierarchy can have an arbitrary depth the O(n^2) nature of RT task dequeues will really hurt. Optimize this by providing space to store the tree path, so we can walk it the other way. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar

sched: fair-group: SMP-nice for group scheduling

2008-04-19T17:45:00Z

Implement SMP nice support for the full group hierarchy. On each load-balance action, compile a sched_domain wide view of the full task_group tree. We compute the domain wide view when walking down the hierarchy, and readjust the weights when walking back up. After collecting and readjusting the domain wide view, we try to balance the tasks within the task_groups. The current approach is a naively balance each task group until we've moved the targeted amount of load. Inspired by Srivatsa Vaddsgiri's previous code and Abhishek Chandra's H-SMP paper. XXX: there will be some numerical issues due to the limited nature of SCHED_LOAD_SCALE wrt to representing a task_groups influence on the total weight. When the tree is deep enough, or the task weight small enough, we'll run out of bits. Signed-off-by: Peter Zijlstra CC: Abhishek Chandra CC: Srivatsa Vaddagiri Signed-off-by: Ingo Molnar

sched: mix tasks and groups

2008-04-19T17:44:59Z

This patch allows tasks and groups to exist in the same cfs_rq. With this change the CFS group scheduling follows a 1/(M+N) model from a 1/(1+N) fairness model where M tasks and N groups exist at the cfs_rq level. [a.p.zijlstra@chello.nl: rt bits and assorted fixes] Signed-off-by: Dhaval Giani Signed-off-by: Srivatsa Vaddagiri Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar

sched: add new set_cpus_allowed_ptr function

2008-04-19T17:44:59Z

Add a new function that accepts a pointer to the "newly allowed cpus" cpumask argument. int set_cpus_allowed_ptr(struct task_struct *p, const cpumask_t *new_mask) The current set_cpus_allowed() function is modified to use the above but this does not result in an ABI change. And with some compiler optimization help, it may not introduce any additional overhead. Additionally, to enforce the read only nature of the new_mask arg, the "const" property is migrated to sub-functions called by set_cpus_allowed. This silences compiler warnings. Signed-off-by: Mike Travis Signed-off-by: Ingo Molnar