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 _prefer_ to be affine to a specific NUMA node.
4) Similar to the previous point but kthreads have a _preferred_ affinity
different than a node. 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 patterns (3 and 4) have at least 4
identified users, with more or less success when it comes to handle
CPU-hotplug operations and CPU isolation.
This is a infrastructure proposal to handle this (after cleanups from 01
to 10).
Changes since v2:
_ Fix a misplaced wake up after kswapd creation
_ Add various acks
Thanks.
Frederic Weisbecker (19):
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: Default affine kthread to its preferred NUMA node
mm: Create/affine kcompactd to its preferred node
mm: Create/affine kswapd to its preferred node
kthread: Implement preferred affinity
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 | 214 ++++++++++++++++--
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, 335 insertions(+), 259 deletions(-)
--
2.46.0