x86/resctrl: Optimize cpumask_any_housekeeping()

With the lack of cpumask_any_andnot_but(), cpumask_any_housekeeping()
has to abuse cpumask_nth() functions.

Update cpumask_any_housekeeping() to use the new cpumask_any_but()
and cpumask_any_andnot_but(). These two functions understand
RESCTRL_PICK_ANY_CPU, which simplifies cpumask_any_housekeeping()
significantly.

Signed-off-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: James Morse <james.morse@arm.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/20250515165855.31452-5-james.morse@arm.com

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index eaae99602b617527f54da94dd363bb0a1a323a6f..25b61e466715727affb30076b5548e1d453aee11 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -47,30 +47,16 @@
 static inline unsigned int
 cpumask_any_housekeeping(const struct cpumask *mask, int exclude_cpu)
 {
-       unsigned int cpu, hk_cpu;
-
-       if (exclude_cpu == RESCTRL_PICK_ANY_CPU)
-               cpu = cpumask_any(mask);
-       else
-               cpu = cpumask_any_but(mask, exclude_cpu);
-
-       /* Only continue if tick_nohz_full_mask has been initialized. */
-       if (!tick_nohz_full_enabled())
-               return cpu;
-
-       /* If the CPU picked isn't marked nohz_full nothing more needs doing. */
-       if (cpu < nr_cpu_ids && !tick_nohz_full_cpu(cpu))
-               return cpu;
+       unsigned int cpu;
 
        /* Try to find a CPU that isn't nohz_full to use in preference */
-       hk_cpu = cpumask_nth_andnot(0, mask, tick_nohz_full_mask);
-       if (hk_cpu == exclude_cpu)
-               hk_cpu = cpumask_nth_andnot(1, mask, tick_nohz_full_mask);
-
-       if (hk_cpu < nr_cpu_ids)
-               cpu = hk_cpu;
+       if (tick_nohz_full_enabled()) {
+               cpu = cpumask_any_andnot_but(mask, tick_nohz_full_mask, exclude_cpu);
+               if (cpu < nr_cpu_ids)
+                       return cpu;
+       }
 
-       return cpu;
+       return cpumask_any_but(mask, exclude_cpu);
 }
 
 struct rdt_fs_context {