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  1. 04 Mar, 2011 4 commits
    • Darren Hart's avatar
      sched: Allow users with sufficient RLIMIT_NICE to change from SCHED_IDLE policy · c02aa73b
      Darren Hart authored 
      The current scheduler implementation returns -EPERM when trying to
change from SCHED_IDLE to SCHED_OTHER or SCHED_BATCH. Since SCHED_IDLE
is considered to be a nice 20 on steroids, changing to another policy
should be allowed provided the RLIMIT_NICE is accounted for.

This patch allows the following test-case to pass with RLIMIT_NICE=40,
but still fail with RLIMIT_NICE=10 when the calling process is run
from a typical shell (nice 0, or 20 in rlimit terms).

int main()
{
	int ret;
	struct sched_param sp;
	sp.sched_priority = 0;

	/* switch to SCHED_IDLE */
	ret = sched_setscheduler(0, SCHED_IDLE, &sp);
	printf("setscheduler IDLE: %d\n", ret);
	if (ret) return ret;

	/* switch back to SCHED_OTHER */
	ret = sched_setscheduler(0, SCHED_OTHER, &sp);
	printf("setscheduler OTHER: %d\n", ret);

	return ret;
}

 $ ulimit -e
 40
 $ ./test
 setscheduler IDLE: 0
 setscheduler OTHER: 0

 $ ulimit -e 10
 $ ulimit -e
 10
 $ ./test
 setscheduler IDLE: 0
 setscheduler OTHER: -1
Signed-off-by: default avatarDarren Hart <dvhart@linux.intel.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Richard Purdie <richard.purdie@linuxfoundation.org>
LKML-Reference: <4D657BEE.4040608@linux.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      c02aa73b
    • Darren Hart's avatar
      sched: Allow SCHED_BATCH to preempt SCHED_IDLE tasks · a2f5c9ab
      Darren Hart authored 
      Perform the test for SCHED_IDLE before testing for SCHED_BATCH (and
ensure idle tasks don't preempt idle tasks) so the non-interactive,
but still important, SCHED_BATCH tasks will run in favor of the very
low priority SCHED_IDLE tasks.
Signed-off-by: default avatarDarren Hart <dvhart@linux.intel.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: default avatarMike Galbraith <efault@gmx.de>
Cc: Richard Purdie <richard.purdie@linuxfoundation.org>
LKML-Reference: <1298408674-3130-2-git-send-email-dvhart@linux.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      a2f5c9ab
    • Ingo Molnar's avatar
      Merge branch 'sched/urgent' into sched/core · e0a92c17
      Ingo Molnar authored 
      Merge reason: Add fixes before applying dependent patches.
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      e0a92c17
    • Balbir Singh's avatar
      sched: Fix sched rt group scheduling when hierachy is enabled · 0c3b9168
      Balbir Singh authored 
      The current sched rt code is broken when it comes to hierarchical
scheduling, this patch fixes two problems

1. It adds redundant enqueuing (harmless) when it finds a queue
   has tasks enqueued, but it has no run time and it is not
   throttled.

2. The most important change is in sched_rt_rq_enqueue/dequeue.
   The code just picks the rt_rq belonging to the current cpu
   on which the period timer runs, the patch fixes it, so that
   the correct rt_se is enqueued/dequeued.

Tested with a simple hierarchy

/c/d, c and d assigned similar runtimes of 50,000 and a while
1 loop runs within "d". Both c and d get throttled, without
the patch, the task just stops running and never runs (depends
on where the sched_rt b/w timer runs). With the patch, the
task is throttled and runs as expected.

[ bharata, suggestions on how to pick the rt_se belong to the
  rt_rq and correct cpu ]
Signed-off-by: default avatarBalbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: default avatarBharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@kernel.org
LKML-Reference: <20110303113435.GA2868@balbir.in.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      0c3b9168
  3. 03 Mar, 2011 29 commits
  5. 02 Mar, 2011 7 commits
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