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authorQuentin Perret <qperret@google.com>2020-04-16 09:59:56 +0100
committerPeter Zijlstra <peterz@infradead.org>2020-04-22 23:10:13 +0200
commiteaf5a92ebde5bca3bb2565616115bd6d579486cd (patch)
tree2aeb36e9b491ab5f5ad9049c5abf2b7d123dab1e
parentdb441bd9f630329c402d5cdd319f11bfcf509fb6 (diff)
sched/core: Fix reset-on-fork from RT with uclamp
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> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Patrick Bellasi <patrick.bellasi@matbug.net> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lkml.kernel.org/r/20200416085956.217587-1-qperret@google.com
-rw-r--r--kernel/sched/core.c9
1 files 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);
}
}