[PATCH 0/6 v4] sched/mm: LRU drain flush on nohz_full

[Frederic Weisbecker <frederic@kernel.org>]

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.

Changes since v3:

* Apply review from Oleg and K Prateek Nayak (handle io_uring kthreads
  and use guard)
  
* Confine this into a new CONFIG_NO_HZ_FULL_WORK because it is still
  experimental.

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
	task/work-v4

HEAD: 87896fa0dc36b421533c9dc85dd32b61eaff887b

Thanks,
	Frederic
---

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/pagevec.h         | 18 ++----------------
 include/linux/sched.h           | 18 ++++++++++++------
 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             |  5 +----
 kernel/sched/isolation.c        | 26 ++++++++++++++++++++++++++
 kernel/sched/sched.h            |  1 +
 kernel/task_work.c              |  9 +++++++--
 kernel/time/Kconfig             | 12 ++++++++++++
 mm/swap.c                       | 30 +++++++++++++++++++++++++++++-
 12 files changed, 122 insertions(+), 33 deletions(-)