Messages in this thread Patch in this message | | | Date | Tue, 14 Apr 2020 19:21:20 +0200 | From | Patrick Bellasi <> | Subject | Re: [PATCH] sched/core: Fix reset-on-fork from RT with uclamp |
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On 14-Apr 17:13, Quentin Perret wrote: > uclamp_fork() resets the uclamp values to their default when the > reset-on-fork flag is set. It also checks whether the task has a RT > policy, and sets its uclamp.min to 1024 accordingly. However, during > reset-on-fork, the task's policy is lowered to SCHED_NORMAL right after, > hence leading to an erroneous uclamp.min setting for the new task if it > was forked from RT.
Right, good catch. Thanks.
> Fix this by removing the unnecessary check on rt_policy() in > uclamp_fork() as this doesn't make sense if the reset-on-fork flag is > set. > > Reported-by: Chitti Babu Theegala <ctheegal@codeaurora.org> > Signed-off-by: Quentin Perret <qperret@google.com>
Fixes: 1a00d999971c ("sched/uclamp: Set default clamps for RT tasks") Reviewed-by: Patrick Bellasi <patrick.bellasi@matbug.net>
> --- > kernel/sched/core.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 3a61a3b8eaa9..9ea3e484eea2 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -1234,10 +1234,6 @@ static void uclamp_fork(struct task_struct *p) > for_each_clamp_id(clamp_id) { > unsigned int clamp_value = uclamp_none(clamp_id); > > - /* By default, RT tasks always get 100% boost */ > - if (unlikely(rt_task(p) && clamp_id == UCLAMP_MIN)) > - clamp_value = uclamp_none(UCLAMP_MAX); > - > uclamp_se_set(&p->uclamp_req[clamp_id], clamp_value, false); > } > } > -- > 2.26.0.110.g2183baf09c-goog >
-- #include <best/regards.h>
Patrick Bellasi
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