Messages in this thread |  | | From | Frederic Weisbecker <> | | Subject | [PATCH 00/20] kthread: Introduce preferred affinity | | Date | Fri, 26 Jul 2024 23:56:36 +0200 |
| |
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
|  |