[PATCH 0/4] sched/fair: fixes in presence of lot of sched_idle tasks

[Vincent Guittot]

This patchset gathers somes cleanups but also improvements and fixes for
scheduling UCs that involved a lot of sched_idle tasks. In such case, the
sched_idle tasks impact significantly the behavior of other tasks whereas
they should not. These patches don't impact other "normal" UCs.

 have foudn these changes while studying Zhang's problem [1] but AFAICT,
 these patches don't fix his problem.

[1] https://lore.kernel.org/lkml/20220810015636.3865248-1-zhangsong34@xxxxxxxxxx/

Vincent Guittot (4):
  sched/fair: make sure to try to detach at least one movable task
  sched/fair: cleanup loop_max and loop_break
  sched/fair: move call to list_last_entry() in detach_tasks
  sched/fair: limit sched slice duration

 kernel/sched/core.c  |  6 +-----
 kernel/sched/fair.c  | 29 +++++++++++++++++------------
 kernel/sched/sched.h |  6 ++++++
 3 files changed, 24 insertions(+), 17 deletions(-)

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2.17.1