Messages in this thread Patch in this message | | | Date | Thu, 16 Apr 2020 09:59:56 +0100 | Subject | [PATCH v2] sched/core: Fix reset-on-fork from RT with uclamp | From | Quentin Perret <> |
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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.
Fix this by removing the unnecessary check on rt_task() in uclamp_fork() as this doesn't make sense if the reset-on-fork flag is set.
Fixes: 1a00d999971c ("sched/uclamp: Set default clamps for RT tasks") Reported-by: Chitti Babu Theegala <ctheegal@codeaurora.org> Reviewed-by: Patrick Bellasi <patrick.bellasi@matbug.net> Signed-off-by: Quentin Perret <qperret@google.com> --- Changes in v2: - Added missing 'Fixes:' tag (Patrick) - Removed unnecessary local variable (Doug, Patrick) --- kernel/sched/core.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3a61a3b8eaa9..9a2fbf98fd6f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1232,13 +1232,8 @@ static void uclamp_fork(struct task_struct *p) return; 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); + uclamp_se_set(&p->uclamp_req[clamp_id], + uclamp_none(clamp_id), false); } } -- 2.26.1.301.g55bc3eb7cb9-goog
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