lkml.org 
[lkml]   [2020]   [Jul]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] sched/deadline: dome some cleanup for push_dl_task()
From
Date
On 7/24/20 9:14 AM, Juri Lelli wrote:
> Hi,
>
> On 07/07/20 00:04, Peng Liu wrote:
>> 'commit 840d719604b0 ("sched/deadline: Update rq_clock of later_rq when pushing a task")'
>> introduced the update_rq_clock() to fix the "used-before-update" bug.
>>
>> 'commit f4904815f97a ("sched/deadline: Fix double accounting of rq/running bw in push & pull")'
>> took away the bug source(add_running_bw()).
>>
>> We no longer need to update rq_clock in advance, let activate_task()
>> worry about that.
>>
>> Signed-off-by: Peng Liu <iwtbavbm@gmail.com>
>> ---
>> kernel/sched/deadline.c | 8 +-------
>> 1 file changed, 1 insertion(+), 7 deletions(-)
>>
>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>> index 504d2f51b0d6..c3fa11f84d93 100644
>> --- a/kernel/sched/deadline.c
>> +++ b/kernel/sched/deadline.c
>> @@ -2104,13 +2104,7 @@ static int push_dl_task(struct rq *rq)
>>
>> deactivate_task(rq, next_task, 0);
>> set_task_cpu(next_task, later_rq->cpu);
>> -
>> - /*
>> - * Update the later_rq clock here, because the clock is used
>> - * by the cpufreq_update_util() inside __add_running_bw().
>> - */
>> - update_rq_clock(later_rq);
>> - activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
>> + activate_task(later_rq, next_task, 0);
>> ret = 1;
> The change looks good to me, since now add_running_bw() is called later
> by enqueue_task_dl(), but rq_clock has already been updated by core's
> enqueue_task().
>
> Daniel, Dietmar, a second pair of eyes (since you authored the commits
> above)?
>
> I'd chage subject to something like "sched/deadline: Stop updating
> rq_clock before pushing a task".

Looks good to me!

Acked-by: Daniel Bristot de Oliveira <bristot@redhat.com>

Thanks
-- Daniel

\
 
 \ /
  Last update: 2020-07-24 17:33    [W:0.070 / U:1.168 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site