lkml.org 
[lkml]   [2011]   [Mar]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [BUGFIX][PATCH] Fix sched rt group scheduling when hierachy is enabled
From
On Thu, Mar 3, 2011 at 7:35 PM, Yong Zhang <yong.zhang0@gmail.com> wrote:
> On Thu, Mar 03, 2011 at 05:04:35PM +0530, Balbir Singh wrote:
>> Fix hierarchical scheduling in sched rt group
>>
>> From: Balbir Singh <balbir@linux.vnet.ibm.com>
>>
>> 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.
>
> You say redundant here, so in fact we don't need it, right?
>

No, not really :) It is required, it is a backup check to see if we
have queued tasks, rt_time of 0 and the runqueue is not throttled, why
should it be dequeued?

>> 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.
>
> Ah, this is true. It is also needed for stable-2.6.33+
>

Yep, we'll need backports to stable versions

Balbir
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2011-03-03 16:31    [W:0.085 / U:0.216 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site