[v4] bitmap: introduce find_random_bit() and use in clocksource

[PATCH v4 0/3] bitmap: introduce find_random_bit() and use in clocksource

Posted by Yury Norov 3 months, 3 weeks ago

nodemasks implement node_random(), which may also be useful for other
subsystems. Generalize the function, and propagate to cpumask API.

v1: https://lore.kernel.org/all/20250604212125.25656-1-yury.norov@gmail.com/
v2: https://lore.kernel.org/all/20250608194536.28130-1-yury.norov@gmail.com/
v3: https://lore.kernel.org/all/20250617200854.60753-1-yury.norov@gmail.com/
v4: return NUMA_NO_NODES instead of MAX_NUMNODES in node_random() (Andrew)

Yury Norov [NVIDIA] (3):
  bitmap: generalize node_random()
  cpumask: introduce cpumask_random()
  clocksource: Improve randomness in clocksource_verify_choose_cpus()

 include/linux/cpumask.h   | 12 ++++++++++++
 include/linux/find.h      |  2 ++
 include/linux/nodemask.h  | 18 +++---------------
 kernel/time/clocksource.c |  5 +----
 lib/find_bit.c            | 24 ++++++++++++++++++++++++
 5 files changed, 42 insertions(+), 19 deletions(-)

-- 
2.43.0

Re: [PATCH v4 0/3] bitmap: introduce find_random_bit() and use in clocksource

Posted by Thomas Gleixner 3 months, 2 weeks ago

On Thu, Jun 19 2025 at 14:26, Yury Norov wrote:
> nodemasks implement node_random(), which may also be useful for other
> subsystems. Generalize the function, and propagate to cpumask API.
>
> v1: https://lore.kernel.org/all/20250604212125.25656-1-yury.norov@gmail.com/
> v2: https://lore.kernel.org/all/20250608194536.28130-1-yury.norov@gmail.com/
> v3: https://lore.kernel.org/all/20250617200854.60753-1-yury.norov@gmail.com/
> v4: return NUMA_NO_NODES instead of MAX_NUMNODES in node_random() (Andrew)
>
> Yury Norov [NVIDIA] (3):
>   bitmap: generalize node_random()
>   cpumask: introduce cpumask_random()
>   clocksource: Improve randomness in clocksource_verify_choose_cpus()

Assuming this goes through the bitmap tree, for the clocksource change:

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

Re: [PATCH v4 0/3] bitmap: introduce find_random_bit() and use in clocksource

Posted by Yury Norov 3 months, 2 weeks ago

On Fri, Jun 20, 2025 at 11:37:07PM +0200, Thomas Gleixner wrote:
> On Thu, Jun 19 2025 at 14:26, Yury Norov wrote:
> > nodemasks implement node_random(), which may also be useful for other
> > subsystems. Generalize the function, and propagate to cpumask API.
> >
> > v1: https://lore.kernel.org/all/20250604212125.25656-1-yury.norov@gmail.com/
> > v2: https://lore.kernel.org/all/20250608194536.28130-1-yury.norov@gmail.com/
> > v3: https://lore.kernel.org/all/20250617200854.60753-1-yury.norov@gmail.com/
> > v4: return NUMA_NO_NODES instead of MAX_NUMNODES in node_random() (Andrew)
> >
> > Yury Norov [NVIDIA] (3):
> >   bitmap: generalize node_random()
> >   cpumask: introduce cpumask_random()
> >   clocksource: Improve randomness in clocksource_verify_choose_cpus()
> 
> Assuming this goes through the bitmap tree, for the clocksource change:
> 
> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

Thanks, applying in bitmap-for-next for testing.