Revert "lib: Restrict cpumask_local_spread to houskeeping CPUs"

This reverts commit 1abdfe706a579a702799fce465bceb9fb01d407c.

This change is broken and not solving any problem it claims to solve.

Revert "lib: Restrict cpumask_local_spread to houskeeping CPUs"

This reverts commit 1abdfe706a579a702799fce465bceb9fb01d407c.

This change is broken and not solving any problem it claims to solve.

Robin reported that cpumask_local_spread() now returns any cpu out of
cpu_possible_mask in case that NOHZ_FULL is disabled (runtime or compile
time). It can also return any offline or not-present CPU in the
housekeeping mask. Before that it was returning a CPU out of
online_cpu_mask.

While the function is racy against CPU hotplug if the caller does not
protect against it, the actual use cases are not caring much about it as
they use it mostly as hint for:

- the user space affinity hint which is unused by the kernel
- memory node selection which is just suboptimal
- network queue affinity which might fail but is handled gracefully

But the occasional fail vs. hotplug is very different from returning
anything from possible_cpu_mask which can have a large amount of offline
CPUs obviously.

The changelog of the commit claims:

"The current implementation of cpumask_local_spread() does not respect
the isolated CPUs, i.e., even if a CPU has been isolated for Real-Time
task, it will return it to the caller for pinning of its IRQ
threads. Having these unwanted IRQ threads on an isolated CPU adds up
to a latency overhead."

The only correct part of this changelog is:

"The current implementation of cpumask_local_spread() does not respect
the isolated CPUs."

Everything else is just disjunct from reality.

Reported-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Nitesh Narayan Lal <nitesh@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: abelits@marvell.com
Cc: davem@davemloft.net
Link: https://lore.kernel.org/r/87y2g26tnt.fsf@nanos.tec.linutronix.de

show more ...

Merge tag 'amba-make-remove-return-void' of https://git.pengutronix.de/git/ukl/linux into devel-stable

Tag for adaptions to struct amba_driver::remove changing prototype

Merge branch 'cpuidle-fix' into fixes

Merge drm/drm-next into drm-intel-gt-next

Backmerging to get a common base for merging topic branches between
drm-intel-next and drm-intel-gt-next.

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@l

Merge drm/drm-next into drm-intel-gt-next

Backmerging to get a common base for merging topic branches between
drm-intel-next and drm-intel-gt-next.

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

show more ...

Merge drm/drm-next into drm-intel-next

sync-up to not fall too much behind.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Merge branch 'for-linus' into for-next

Back-merge of 5.11-devel branch for syncing the result changes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

Merge tag 'asoc-fix-v5.11-rc2' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v5.11

A collection of mostly driver specific fixes, plus a maintainers

Merge tag 'asoc-fix-v5.11-rc2' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v5.11

A collection of mostly driver specific fixes, plus a maintainership
update for TI and a fix for DAPM driver removal paths.

show more ...

Merge drm/drm-next into drm-misc-next

Staying in sync to drm-next, and to be able to pull ttm fixes.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

Merge tag 'v5.11-rc1' into spi-5.11

Linux 5.11-rc1

Merge tag 'v5.11-rc1' into regulator-5.11

Linux 5.11-rc1

Merge tag 'v5.11-rc1' into asoc-5.11

Linux 5.11-rc1

Merge remote-tracking branch 'torvalds/master' into perf/core

To pick up fixes and check what UAPI headers need to be synched.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Merge tag 'sched-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Thomas Gleixner:

- migrate_disable/enable() support which originates from the

Merge tag 'sched-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Thomas Gleixner:

- migrate_disable/enable() support which originates from the RT tree
and is now a prerequisite for the new preemptible kmap_local() API
which aims to replace kmap_atomic().

- A fair amount of topology and NUMA related improvements

- Improvements for the frequency invariant calculations

- Enhanced robustness for the global CPU priority tracking and decision
making

- The usual small fixes and enhancements all over the place

* tag 'sched-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits)
sched/fair: Trivial correction of the newidle_balance() comment
sched/fair: Clear SMT siblings after determining the core is not idle
sched: Fix kernel-doc markup
x86: Print ratio freq_max/freq_base used in frequency invariance calculations
x86, sched: Use midpoint of max_boost and max_P for frequency invariance on AMD EPYC
x86, sched: Calculate frequency invariance for AMD systems
irq_work: Optimize irq_work_single()
smp: Cleanup smp_call_function*()
irq_work: Cleanup
sched: Limit the amount of NUMA imbalance that can exist at fork time
sched/numa: Allow a floating imbalance between NUMA nodes
sched: Avoid unnecessary calculation of load imbalance at clone time
sched/numa: Rename nr_running and break out the magic number
sched: Make migrate_disable/enable() independent of RT
sched/topology: Condition EAS enablement on FIE support
arm64: Rebuild sched domains on invariance status changes
sched/topology,schedutil: Wrap sched domains rebuild
sched/uclamp: Allow to reset a task uclamp constraint value
sched/core: Fix typos in comments
Documentation: scheduler: fix information on arch SD flags, sched_domain and sched_debug
...

show more ...

Merge branch 'next' into for-linus

Prepare input updates for 5.11 merge window.

Merge branch 'sched/core' into core/mm

Pull the migrate disable mechanics which is a prerequisite for preemptible
kmap_local().

Merge tag 'v5.9' into next

Sync up with mainline to bring in the latest DTS files.

Merge branch 'sched/migrate-disable'

sched,rt: Use cpumask_any*_distribute()

Replace a bunch of cpumask_any*() instances with
cpumask_any*_distribute(), by injecting this little bit of random in
cpu selection, we reduce the chance two

sched,rt: Use cpumask_any*_distribute()

Replace a bunch of cpumask_any*() instances with
cpumask_any*_distribute(), by injecting this little bit of random in
cpu selection, we reduce the chance two competing balance operations
working off the same lowest_mask pick the same CPU.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102347.190759694@infradead.org

show more ...

Merge drm/drm-next into drm-intel-next-queued

Sync drm-intel-gt-next here so we can have an unified fixes flow.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Merge branch 'for-linus' into for-next

Back-merge to apply the tasklet conversion patches that are based
on the already applied tasklet API changes on 5.9-rc4.

Signed-off-by: Takashi Iwai <tiwai@su

Merge branch 'for-linus' into for-next

Back-merge to apply the tasklet conversion patches that are based
on the already applied tasklet API changes on 5.9-rc4.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

Merge branch 'topic/tasklet-convert' into for-linus

Pull tasklet API conversions.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

Merge branch 'master' into for-next

Sync with Linus' branch in order to be able to apply fixups
of more recent patches.

Merge tag 'v5.9-rc2' into regulator-5.9

Linux 5.9-rc2

Merge tag 'v5.9-rc2' into asoc-5.9

Linux 5.9-rc2

Merge tag 'v5.9-rc2' into drm-misc-fixes

Backmerge requested by Tomi for a fix to omap inconsistent
locking state issue, and because we need at least v5.9-rc2 now.

Signed-off-by: Maarten Lankhorst

Merge tag 'v5.9-rc2' into drm-misc-fixes

Backmerge requested by Tomi for a fix to omap inconsistent
locking state issue, and because we need at least v5.9-rc2 now.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

show more ...