linux-kernel - [PATCH v2 0/4] cpumask: add missing API and simplify cpumask_any

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Message-ID: <20250427185242.221974-1-yury.norov@gmail.com>
Date: Sun, 27 Apr 2025 14:52:27 -0400
From: Yury Norov <yury.norov@...il.com>
To: Reinette Chatre <reinette.chatre@...el.com>,
	James Morse <james.morse@....com>
Cc: "Yury Norov [NVIDIA]" <yury.norov@...il.com>,
	Tony Luck <tony.luck@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 0/4] cpumask: add missing API and simplify cpumask_any_housekeeping()

From: Yury Norov [NVIDIA] <yury.norov@...il.com>

cpumask library missed some flavors of cpumask_any_but(), which makes
users to workaround it by using less efficient cpumask_nth() functions

This series adds missing cpumask_any_andnot_but() and makes
cpumask_any_but() understanding the RESCTRL_PICK_ANY_CPU hint.
This simplifies cpumask_any_housekeeping() significantly.

v1: https://lore.kernel.org/all/20250407153856.133093-1-yury.norov@gmail.com/
v2:
 - switch cpumask_any_but() functions to signed type for CPU (Reinette);
 - change name for the new function to cpumask_any_andnot_but() (James);
 - drop O(n*log(n)) comment. cpumask_nth() is slower, but still linear.

Yury Norov [NVIDIA] (4):
  cpumask: relax cpumask_any_but()
  find: add find_first_andnot_bit()
  cpumask: add cpumask_{first,next}_andnot() API
  x86/resctrl: optimize cpumask_any_housekeeping()

 arch/x86/kernel/cpu/resctrl/internal.h | 28 +++-------
 include/linux/cpumask.h                | 75 ++++++++++++++++++++++++--
 include/linux/find.h                   | 25 +++++++++
 lib/find_bit.c                         | 11 ++++
 4 files changed, 114 insertions(+), 25 deletions(-)

-- 
2.43.0