[RFC PATCH 0/6] mm: LRU drain flush on nohz_full

[Frederic Weisbecker]

When LRUs are pending, the drain can be triggered remotely, whether the
remote CPU is running in userspace in nohz_full mode or not. This kind
of noise is expected to be caused by preparatory work before a task
runs isolated in userspace. This patchset is a proposal to flush that
before the task starts its critical work in userspace.

Frederic Weisbecker (6):
  task_work: Provide means to check if a work is queued
  sched/fair: Use task_work_queued() on numa_work
  sched: Use task_work_queued() on cid_work
  tick/nohz: Move nohz_full related fields out of hot task struct's
    places
  sched/isolation: Introduce isolated task work
  mm: Drain LRUs upon resume to userspace on nohz_full CPUs

 include/linux/sched.h           | 15 +++++++++------
 include/linux/sched/isolation.h | 17 +++++++++++++++++
 include/linux/swap.h            |  1 +
 include/linux/task_work.h       | 12 ++++++++++++
 kernel/sched/core.c             |  6 ++----
 kernel/sched/fair.c             |  4 +---
 kernel/sched/isolation.c        | 32 ++++++++++++++++++++++++++++++++
 kernel/sched/sched.h            |  1 +
 kernel/task_work.c              |  1 +
 mm/swap.c                       |  5 ++++-
 10 files changed, 80 insertions(+), 14 deletions(-)

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2.45.2