Affining kthreads follow either of three existing different patterns:
1) Per-CPU kthreads must stay affine to a single CPU and never execute
relevant code on any other CPU. This is currently handled by smpboot
code which takes care of CPU-hotplug operations.
2) Kthreads that _have_ to be affine to a specific set of CPUs and can't
run anywhere else. The affinity is set through kthread_bind_mask()
and the subsystem takes care by itself to handle CPU-hotplug operations.
3) Kthreads that have a _preferred_ affinity but that can run anywhere
without breaking correctness. Userspace can overwrite the affinity.
It is set manually like any other task and CPU-hotplug is supposed
to be handled by the relevant subsystem so that the task is properly
reaffined whenever a given CPU from the preferred affinity comes up
or down. Also care must be taken so that the preferred affinity
doesn't cross housekeeping cpumask boundaries.
Currently the preferred affinity pattern has at least 4 identified
users, with more or less success when it comes to handle CPU-hotplug
operations and housekeeping cpumask.
This is a infrastructure proposal to handle this (after cleanups from 01
to 10).
Frederic Weisbecker (20):
arm/bL_switcher: Use kthread_run_on_cpu()
x86/resctrl: Use kthread_run_on_cpu()
firmware: stratix10-svc: Use kthread_run_on_cpu()
scsi: bnx2fc: Use kthread_create_on_cpu()
scsi: bnx2i: Use kthread_create_on_cpu()
scsi: qedi: Use kthread_create_on_cpu()
soc/qman: test: Use kthread_run_on_cpu()
kallsyms: Use kthread_run_on_cpu()
lib: test_objpool: Use kthread_run_on_cpu()
net: pktgen: Use kthread_create_on_node()
kthread: Make sure kthread hasn't started while binding it
kthread: Implement preferred affinity
mm: Make Kcompactd use kthread's preferred affinity
mm: Allocate kcompactd on its node
mm: Make kswapd use kthread's preferred affinity
mm: Allocate kswapd on its node
rcu: Use kthread preferred affinity for RCU boost
kthread: Unify kthread_create_on_cpu() and
kthread_create_worker_on_cpu() automatic format
treewide: Introduce kthread_run_worker[_on_cpu]()
rcu: Use kthread preferred affinity for RCU exp kworkers
arch/arm/common/bL_switcher.c | 10 +-
arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 28 +--
arch/x86/kvm/i8254.c | 2 +-
crypto/crypto_engine.c | 2 +-
drivers/cpufreq/cppc_cpufreq.c | 2 +-
drivers/firmware/stratix10-svc.c | 9 +-
drivers/gpu/drm/drm_vblank_work.c | 2 +-
.../drm/i915/gem/selftests/i915_gem_context.c | 2 +-
drivers/gpu/drm/i915/gt/selftest_execlists.c | 2 +-
drivers/gpu/drm/i915/gt/selftest_hangcheck.c | 2 +-
drivers/gpu/drm/i915/gt/selftest_slpc.c | 2 +-
drivers/gpu/drm/i915/selftests/i915_request.c | 8 +-
drivers/gpu/drm/msm/disp/msm_disp_snapshot.c | 2 +-
drivers/gpu/drm/msm/msm_atomic.c | 2 +-
drivers/gpu/drm/msm/msm_gpu.c | 2 +-
drivers/gpu/drm/msm/msm_kms.c | 2 +-
.../platform/chips-media/wave5/wave5-vpu.c | 2 +-
drivers/net/dsa/mv88e6xxx/chip.c | 2 +-
drivers/net/ethernet/intel/ice/ice_dpll.c | 2 +-
drivers/net/ethernet/intel/ice/ice_gnss.c | 2 +-
drivers/net/ethernet/intel/ice/ice_ptp.c | 2 +-
drivers/platform/chrome/cros_ec_spi.c | 2 +-
drivers/ptp/ptp_clock.c | 2 +-
drivers/scsi/bnx2fc/bnx2fc_fcoe.c | 7 +-
drivers/scsi/bnx2i/bnx2i_init.c | 7 +-
drivers/scsi/qedi/qedi_main.c | 6 +-
drivers/soc/fsl/qbman/qman_test_stash.c | 6 +-
drivers/spi/spi.c | 2 +-
drivers/usb/typec/tcpm/tcpm.c | 2 +-
drivers/vdpa/vdpa_sim/vdpa_sim.c | 2 +-
drivers/watchdog/watchdog_dev.c | 2 +-
fs/erofs/zdata.c | 2 +-
include/linux/cpuhotplug.h | 1 +
include/linux/kthread.h | 56 +++++-
kernel/kallsyms_selftest.c | 4 +-
kernel/kthread.c | 162 +++++++++++++++---
kernel/rcu/tree.c | 94 ++--------
kernel/rcu/tree_plugin.h | 11 +-
kernel/workqueue.c | 2 +-
lib/test_objpool.c | 19 +-
mm/compaction.c | 43 +----
mm/vmscan.c | 8 +-
net/core/pktgen.c | 7 +-
net/dsa/tag_ksz.c | 2 +-
net/dsa/tag_ocelot_8021q.c | 2 +-
net/dsa/tag_sja1105.c | 2 +-
46 files changed, 284 insertions(+), 258 deletions(-)
--
2.45.2