linux-toradex.git/kernel/sched_rt.c, branch tegra-10.9.4

sched: Simplify sys_sched_rr_get_interval() system call

2009-09-21T07:53:55+00:00

By removing the need for it to know details of scheduling classes.

This allows PlugSched to define orthogonal scheduling classes.

Signed-off-by: Peter Williams 
Acked-by: Peter Zijlstra 
Cc: Mike Galbraith 
LKML-Reference: <06d1b89ee15a0eef82d7.1253496713@mudlark.pw.nest>
Signed-off-by: Ingo Molnar

sched: Rename sync arguments

2009-09-15T14:51:30+00:00

In order to extend the functions to have more than 1 flag (sync),
rename the argument to flags, and explicitly define a WF_ space for
individual flags.

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

sched: Rename select_task_rq() argument

2009-09-15T14:51:29+00:00

In order to be able to rename the sync argument, we need to rename
the current flag argument.

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

sched: Hook sched_balance_self() into sched_class::select_task_rq()

2009-09-15T14:01:04+00:00

Rather ugly patch to fully place the sched_balance_self() code
inside the fair class.

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

sched: Scale down cpu_power due to RT tasks

2009-09-04T08:09:55+00:00

Keep an average on the amount of time spend on RT tasks and use
that fraction to scale down the cpu_power for regular tasks.

Signed-off-by: Peter Zijlstra 
Tested-by: Andreas Herrmann 
Acked-by: Andreas Herrmann 
Acked-by: Gautham R Shenoy 
Cc: Balbir Singh 
LKML-Reference: <20090901083826.287778431@chello.nl>
Signed-off-by: Ingo Molnar

sched: Fix cpupri build on !CONFIG_SMP

2009-08-02T13:15:51+00:00

This build bug:

 In file included from kernel/sched.c:1765:
 kernel/sched_rt.c: In function ‘has_pushable_tasks’:
 kernel/sched_rt.c:1069: error: ‘struct rt_rq’ has no member named ‘pushable_tasks’
 kernel/sched_rt.c: In function ‘pick_next_task_rt’:
 kernel/sched_rt.c:1084: error: ‘struct rq’ has no member named ‘post_schedule’

Triggers because both pushable_tasks and post_schedule are
SMP-only fields.

Move pushable_tasks() to the SMP section and #ifdef the post_schedule use.

Cc: Gregory Haskins 
Cc: Peter Zijlstra 
LKML-Reference: <20090729150422.17691.55590.stgit@dev.haskins.net>
Signed-off-by: Ingo Molnar

sched: Add debug check to task_of()

2009-08-02T12:26:14+00:00

A frequent mistake appears to be to call task_of() on a
scheduler entity that is not actually a task, which can result
in a wild pointer.

Add a check to catch these mistakes.

Suggested-by: Ingo Molnar 
Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

sched: Fully integrate cpus_active_map and root-domain code

2009-08-02T12:26:12+00:00

Reflect "active" cpus in the rq->rd->online field, instead of
the online_map.

The motivation is that things that use the root-domain code
(such as cpupri) only care about cpus classified as "active"
anyway. By synchronizing the root-domain state with the active
map, we allow several optimizations.

For instance, we can remove an extra cpumask_and from the
scheduler hotpath by utilizing rq->rd->online (since it is now
a cached version of cpu_active_map & rq->rd->span).

Signed-off-by: Gregory Haskins 
Acked-by: Peter Zijlstra 
Acked-by: Max Krasnyansky 
Signed-off-by: Peter Zijlstra 
LKML-Reference: <20090730145723.25226.24493.stgit@dev.haskins.net>
Signed-off-by: Ingo Molnar

sched: Enhance the pre/post scheduling logic

2009-08-02T12:26:10+00:00

We currently have an explicit "needs_post" vtable method which
returns a stack variable for whether we should later run
post-schedule.  This leads to an awkward exchange of the
variable as it bubbles back up out of the context switch. Peter
Zijlstra observed that this information could be stored in the
run-queue itself instead of handled on the stack.

Therefore, we revert to the method of having context_switch
return void, and update an internal rq->post_schedule variable
when we require further processing.

In addition, we fix a race condition where we try to access
current->sched_class without holding the rq->lock.  This is
technically racy, as the sched-class could change out from
under us.  Instead, we reference the per-rq post_schedule
variable with the runqueue unlocked, but with preemption
disabled to see if we need to reacquire the rq->lock.

Finally, we clean the code up slightly by removing the #ifdef
CONFIG_SMP conditionals from the schedule() call, and implement
some inline helper functions instead.

This patch passes checkpatch, and rt-migrate.

Signed-off-by: Gregory Haskins 
Signed-off-by: Peter Zijlstra 
LKML-Reference: <20090729150422.17691.55590.stgit@dev.haskins.net>
Signed-off-by: Ingo Molnar

sched_rt: Fix overload bug on rt group scheduling

2009-07-10T08:43:29+00:00

Fixes an easily triggerable BUG() when setting process affinities.

Make sure to count the number of migratable tasks in the same place:
the root rt_rq. Otherwise the number doesn't make sense and we'll hit
the BUG in set_cpus_allowed_rt().

Also, make sure we only count tasks, not groups (this is probably
already taken care of by the fact that rt_se->nr_cpus_allowed will be 0
for groups, but be more explicit)

Tested-by: Thomas Gleixner 
CC: stable@kernel.org
Signed-off-by: Peter Zijlstra 
Acked-by: Gregory Haskins 
LKML-Reference: <1247067476.9777.57.camel@twins>
Signed-off-by: Ingo Molnar