mbox series

[0/3,v3] hrtimer: Fix timers queued locally from offline CPUs

Message ID 20241231170712.149394-1-frederic@kernel.org (mailing list archive)
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Series hrtimer: Fix timers queued locally from offline CPUs | expand

Message

Frederic Weisbecker Dec. 31, 2024, 5:07 p.m. UTC 
5c0930ccaad5 ("hrtimers: Push pending hrtimers away from outgoing CPU earlier")
was introduced to fix stalls with scheduler bandwidth timers getting
migrated while some kthreads handling CPU hotplug rely on bandwidth.

However this has introduced several other issues which used to be
confined to RCU. But not anymore as it is spreading to hotplug code
itself (https://lore.kernel.org/all/20241213203739.1519801-1-usamaarif642@gmail.com/)

Instead of introducing yet another new hackery, fix the problem in
hrtimers for everyone.

Changes since v2:

* Fix and add some tags
* Fix extra newlines

Frederic Weisbecker (3):
  hrtimers: Force migrate away hrtimers queued after
    CPUHP_AP_HRTIMERS_DYING
  rcu: Remove swake_up_one_online() bandaid
  Revert "rcu/nocb: Fix rcuog wake-up from offline softirq"

 include/linux/hrtimer_defs.h |  1 +
 kernel/rcu/tree.c            | 34 +----------------------
 kernel/rcu/tree_exp.h        |  2 +-
 kernel/rcu/tree_nocb.h       | 10 ++-----
 kernel/time/hrtimer.c        | 53 +++++++++++++++++++++++++++++++++---
 5 files changed, 54 insertions(+), 46 deletions(-)