[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20250829154814.47015-1-frederic@kernel.org>
Date: Fri, 29 Aug 2025 17:47:41 +0200
From: Frederic Weisbecker <frederic@...nel.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Frederic Weisbecker <frederic@...nel.org>,
Tejun Heo <tj@...nel.org>,
Michal Hocko <mhocko@...e.com>,
Marco Crivellari <marco.crivellari@...e.com>,
Thomas Gleixner <tglx@...utronix.de>,
Peter Zijlstra <peterz@...radead.org>,
Waiman Long <longman@...hat.com>
Subject: [PATCH 00/33 v2] cpuset/isolation: Honour kthreads preferred affinity
Hi,
The kthread code was enhanced lately to provide an infrastructure which
manages the preferred affinity of unbound kthreads (node or custom
cpumask) against housekeeping constraints and CPU hotplug events.
One crucial missing piece is cpuset: when an isolated partition is
created, deleted, or its CPUs updated, all the unbound kthreads in the
top cpuset are affine to _all_ the non-isolated CPUs, possibly breaking
their preferred affinity along the way
Solve this with performing the kthreads affinity update from cpuset to
the kthreads consolidated relevant code instead so that preferred
affinities are honoured.
The dispatch of the new cpumasks to workqueues and kthreads is performed
by housekeeping, as per the nice Tejun's suggestion.
As a welcome side effect, HK_TYPE_DOMAIN then integrates both the set
from isolcpus= and cpuset isolated partitions. Housekeeping cpumasks are
now modifyable with specific synchronization. A big step toward making
nohz_full= also mutable through cpuset in the future.
Changes since v1:
- Drop the housekeeping lock and use RCU to synchronize housekeeping
against cpuset changes.
- Add housekeeping documentation
- Simplify CPU hotplug handling
- Collect ack from Shakeel Butt
- Handle sched/arm64's task fallback cpumask move to HK_TYPE_DOMAIN
- Fix genirq kthreads affinity
- Add missing kernel doc
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
kthread/core-v2
HEAD: 092784f7df0aa6415c91ae5edc1c1a72603b5c50
Thanks,
Frederic
---
Frederic Weisbecker (32):
sched/isolation: Remove housekeeping static key
PCI: Protect against concurrent change of housekeeping cpumask
cpu: Revert "cpu/hotplug: Prevent self deadlock on CPU hot-unplug"
memcg: Prepare to protect against concurrent isolated cpuset change
mm: vmstat: Prepare to protect against concurrent isolated cpuset change
sched/isolation: Save boot defined domain flags
cpuset: Convert boot_hk_cpus to use HK_TYPE_DOMAIN_BOOT
driver core: cpu: Convert /sys/devices/system/cpu/isolated to use HK_TYPE_DOMAIN_BOOT
net: Keep ignoring isolated cpuset change
block: Protect against concurrent isolated cpuset change
cpu: Provide lockdep check for CPU hotplug lock write-held
cpuset: Provide lockdep check for cpuset lock held
sched/isolation: Convert housekeeping cpumasks to rcu pointers
cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset
sched/isolation: Flush memcg workqueues on cpuset isolated partition change
sched/isolation: Flush vmstat workqueues on cpuset isolated partition change
cpuset: Propagate cpuset isolation update to workqueue through housekeeping
cpuset: Remove cpuset_cpu_is_isolated()
sched/isolation: Remove HK_TYPE_TICK test from cpu_is_isolated()
PCI: Remove superfluous HK_TYPE_WQ check
kthread: Refine naming of affinity related fields
kthread: Include unbound kthreads in the managed affinity list
kthread: Include kthreadd to the managed affinity list
kthread: Rely on HK_TYPE_DOMAIN for preferred affinity management
sched: Switch the fallback task allowed cpumask to HK_TYPE_DOMAIN
sched/arm64: Move fallback task cpumask to HK_TYPE_DOMAIN
kthread: Honour kthreads preferred affinity after cpuset changes
kthread: Comment on the purpose and placement of kthread_affine_node() call
kthread: Add API to update preferred affinity on kthread runtime
kthread: Document kthread_affine_preferred()
genirq: Correctly handle preferred kthreads affinity
doc: Add housekeeping documentation
Gabriele Monaco (1):
cgroup/cpuset: Fail if isolated and nohz_full don't leave any housekeeping
Documentation/cpu_isolation/housekeeping.rst | 111 +++++++++++++++
arch/arm64/kernel/cpufeature.c | 18 ++-
block/blk-mq.c | 6 +-
drivers/base/cpu.c | 2 +-
drivers/pci/pci-driver.c | 50 ++++---
include/linux/cpu.h | 4 +
include/linux/cpuhplock.h | 1 +
include/linux/cpuset.h | 8 +-
include/linux/kthread.h | 2 +
include/linux/memcontrol.h | 4 +
include/linux/mmu_context.h | 2 +-
include/linux/percpu-rwsem.h | 1 +
include/linux/sched/isolation.h | 30 +++--
include/linux/vmstat.h | 2 +
include/linux/workqueue.h | 2 +-
init/Kconfig | 1 +
kernel/cgroup/cpuset.c | 131 +++++++++++++-----
kernel/cpu.c | 42 +++---
kernel/irq/manage.c | 47 ++++---
kernel/kthread.c | 195 +++++++++++++++++++--------
kernel/sched/isolation.c | 185 ++++++++++++++++---------
kernel/sched/sched.h | 4 +
kernel/workqueue.c | 2 +-
mm/memcontrol.c | 25 +++-
mm/vmstat.c | 15 ++-
net/core/net-sysfs.c | 2 +-
26 files changed, 639 insertions(+), 253 deletions(-)
Powered by blists - more mailing lists