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Subject[PATCH v3 00/54] lib/bitmap: optimize bitmap_weight() usage
Date
In many cases people use bitmap_weight()-based functions to compare
the result against a number of expression:

if (cpumask_weight(mask) > 1)
do_something();

This may take considerable amount of time on many-cpus machines because
cpumask_weight() will traverse every word of underlying cpumask
unconditionally.

We can significantly improve on it for many real cases if stop traversing
the mask as soon as we count cpus to any number greater than 1:

if (cpumask_weight_gt(mask, 1))
do_something();

The first part of series converts cpumask_weight() to cpumask_empty()
if the number to compare with is 0. Ditto for bitmap_weigth() and
nodes_weight().

In the 2nd part of the series bitmap_weight_cmp() is added together with
bitmap_weight_{eq,gt,ge,lt,le} wrappers on top of it. Corresponding
wrappers for cpumask and nodemask are added as well.

v1: https://lkml.org/lkml/2021/11/27/339
v2: https://lkml.org/lkml/2021/12/18/241
v3:
- drop subseries for possible, present and active cpumasks. Will
submit it separately if needed;
- split patches per subsystems as requested by Greg and Michał;
- trim the recipient list. Add drivers and arch maintainers to
corresponding patches only.

Yury Norov (54):
net/dsa: don't use bitmap_weight() in b53_arl_read()
net/ethernet: don't use bitmap_weight() in bcm_sysport_rule_set()
thermal/intel: don't use bitmap_weight() in end_power_clamp()
net: mellanox: fix open-coded for_each_set_bit()
nds32: perf: replace bitmap_weight with bitmap_empty where appropriate
x86/kvm: replace bitmap_weight with bitmap_empty where appropriate
gpu: drm: replace bitmap_weight with bitmap_empty where appropriate
net: ethernet: replace bitmap_weight with bitmap_empty for intel
net: ethernet: replace bitmap_weight with bitmap_empty for Marvell
net: ethernet: replace bitmap_weight with bitmap_empty for qlogic
perf: replace bitmap_weight with bitmap_empty where appropriate
tools/perf: replace bitmap_weight with bitmap_empty where appropriate
arch/alpha: replace cpumask_weight with cpumask_empty where
appropriate
arch/ia64: replace cpumask_weight with cpumask_empty where appropriate
arch/x86: replace cpumask_weight with cpumask_empty where appropriate
cpufreq: replace cpumask_weight with cpumask_empty where appropriate
gpu: drm: replace cpumask_weight with cpumask_empty where appropriate
drivers/infiniband: replace cpumask_weight with cpumask_empty where
appropriate
drivers/irqchip: replace cpumask_weight with cpumask_empty where
appropriate
kernel/irq: replace cpumask_weight with cpumask_empty where
appropriate
kernel: replace cpumask_weight with cpumask_empty in padata.c
rcu: replace cpumask_weight with cpumask_empty where appropriate
sched: replace cpumask_weight with cpumask_empty where appropriate
time: replace cpumask_weight with cpumask_empty in clocksource.c
mm/vmstat: replace cpumask_weight with cpumask_empty where appropriate
arch/x86: replace nodes_weight with nodes_empty where appropriate
lib/bitmap: add bitmap_weight_{cmp, eq, gt, ge, lt, le} functions
arch/x86: replace bitmap_weight with bitmap_weight_{eq,gt,ge,lt,le}
where appropriate
drivers/iio: replace bitmap_weight() with bitmap_weight_{eq,gt} where
appropriate
drivers/memstick: replace bitmap_weight with bitmap_weight_eq where
appropriate
net: ethernet: replace bitmap_weight with bitmap_weight_eq for intel
net: ethernet: replace bitmap_weight with bitmap_weight_{eq,gt} for
OcteonTX2
net: ethernet: replace bitmap_weight with
bitmap_weight_{eq,gt,ge,lt,le} for mellanox
perf: replace bitmap_weight with bitmap_weight_eq for ThunderX2
drivers/staging: replace bitmap_weight with bitmap_weight_le for
tegra-video
lib/cpumask: add cpumask_weight_{eq,gt,ge,lt,le}
arch/ia64: replace cpumask_weight with cpumask_weight_eq in mm/tlb.c
arch/mips: replace cpumask_weight with cpumask_weight_{eq, ...} where
appropriate
arch/powerpc: replace cpumask_weight with cpumask_weight_{eq, ...}
where appropriate
arch/s390: replace cpumask_weight with cpumask_weight_eq where
appropriate
arch/x86: replace cpumask_weight with cpumask_weight_eq where
appropriate
firmware: pcsi: replace cpumask_weight with cpumask_weight_eq
drivers/hv: replace cpumask_weight with cpumask_weight_eq
infiniband: replace cpumask_weight with cpumask_weight_{eq, ...} where
appropriate
scsi: replace cpumask_weight with cpumask_weight_gt
soc: replace cpumask_weight with cpumask_weight_lt
sched: replace cpumask_weight with cpumask_weight_eq where appropriate
kernel/time: replace cpumask_weight with cpumask_weight_eq where
appropriate
lib/nodemask: add nodemask_weight_{eq,gt,ge,lt,le}
acpi: replace nodes__weight with nodes_weight_ge for numa
mm: replace nodes_weight with nodes_weight_eq in mempolicy
lib/nodemask: add num_node_state_eq()
tools/bitmap: sync bitmap_weight
MAINTAINERS: add cpumask and nodemask files to BITMAP_API

MAINTAINERS | 4 +
arch/alpha/kernel/process.c | 2 +-
arch/ia64/kernel/setup.c | 2 +-
arch/ia64/mm/tlb.c | 2 +-
arch/mips/cavium-octeon/octeon-irq.c | 4 +-
arch/mips/kernel/crash.c | 2 +-
arch/nds32/kernel/perf_event_cpu.c | 2 +-
arch/powerpc/kernel/smp.c | 2 +-
arch/powerpc/kernel/watchdog.c | 2 +-
arch/powerpc/xmon/xmon.c | 4 +-
arch/s390/kernel/perf_cpum_cf.c | 2 +-
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 16 ++--
arch/x86/kernel/smpboot.c | 4 +-
arch/x86/kvm/hyperv.c | 8 +-
arch/x86/mm/amdtopology.c | 2 +-
arch/x86/mm/mmio-mod.c | 2 +-
arch/x86/mm/numa_emulation.c | 4 +-
arch/x86/platform/uv/uv_nmi.c | 2 +-
drivers/acpi/numa/srat.c | 2 +-
drivers/cpufreq/qcom-cpufreq-hw.c | 2 +-
drivers/cpufreq/scmi-cpufreq.c | 2 +-
drivers/firmware/psci/psci_checker.c | 2 +-
drivers/gpu/drm/i915/i915_pmu.c | 2 +-
drivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c | 2 +-
drivers/hv/channel_mgmt.c | 4 +-
drivers/iio/dummy/iio_simple_dummy_buffer.c | 4 +-
drivers/iio/industrialio-trigger.c | 2 +-
drivers/infiniband/hw/hfi1/affinity.c | 13 ++-
drivers/infiniband/hw/qib/qib_file_ops.c | 2 +-
drivers/infiniband/hw/qib/qib_iba7322.c | 2 +-
drivers/irqchip/irq-bcm6345-l1.c | 2 +-
drivers/memstick/core/ms_block.c | 4 +-
drivers/net/dsa/b53/b53_common.c | 6 +-
drivers/net/ethernet/broadcom/bcmsysport.c | 6 +-
.../net/ethernet/intel/ice/ice_virtchnl_pf.c | 4 +-
.../net/ethernet/intel/ixgbe/ixgbe_sriov.c | 2 +-
.../marvell/octeontx2/nic/otx2_ethtool.c | 2 +-
.../marvell/octeontx2/nic/otx2_flows.c | 8 +-
.../ethernet/marvell/octeontx2/nic/otx2_pf.c | 2 +-
drivers/net/ethernet/mellanox/mlx4/cmd.c | 33 +++-----
drivers/net/ethernet/mellanox/mlx4/eq.c | 4 +-
drivers/net/ethernet/mellanox/mlx4/fw.c | 4 +-
drivers/net/ethernet/mellanox/mlx4/main.c | 2 +-
drivers/net/ethernet/qlogic/qed/qed_rdma.c | 4 +-
drivers/net/ethernet/qlogic/qed/qed_roce.c | 2 +-
drivers/perf/arm-cci.c | 2 +-
drivers/perf/arm_pmu.c | 4 +-
drivers/perf/hisilicon/hisi_uncore_pmu.c | 2 +-
drivers/perf/thunderx2_pmu.c | 4 +-
drivers/perf/xgene_pmu.c | 2 +-
drivers/scsi/lpfc/lpfc_init.c | 2 +-
drivers/soc/fsl/qbman/qman_test_stash.c | 2 +-
drivers/staging/media/tegra-video/vi.c | 2 +-
drivers/thermal/intel/intel_powerclamp.c | 9 +--
include/linux/bitmap.h | 80 +++++++++++++++++++
include/linux/cpumask.h | 50 ++++++++++++
include/linux/nodemask.h | 40 ++++++++++
kernel/irq/affinity.c | 2 +-
kernel/padata.c | 2 +-
kernel/rcu/tree_nocb.h | 4 +-
kernel/rcu/tree_plugin.h | 2 +-
kernel/sched/core.c | 10 +--
kernel/sched/topology.c | 4 +-
kernel/time/clockevents.c | 2 +-
kernel/time/clocksource.c | 2 +-
lib/bitmap.c | 21 +++++
mm/mempolicy.c | 2 +-
mm/page_alloc.c | 2 +-
mm/vmstat.c | 4 +-
tools/include/linux/bitmap.h | 44 ++++++++++
tools/lib/bitmap.c | 20 +++++
tools/perf/builtin-c2c.c | 4 +-
tools/perf/util/pmu.c | 2 +-
73 files changed, 374 insertions(+), 142 deletions(-)

--
2.30.2

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