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YuryNorovbp3tk0v
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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
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arch/x86/kernel/cpu/resctrl/internal.h

Lines changed: 7 additions & 21 deletions
Original file line numberDiff line numberDiff line change
@@ -47,30 +47,16 @@
4747
static inline unsigned int
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cpumask_any_housekeeping(const struct cpumask *mask, int exclude_cpu)
4949
{
50-
unsigned int cpu, hk_cpu;
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52-
if (exclude_cpu == RESCTRL_PICK_ANY_CPU)
53-
cpu = cpumask_any(mask);
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else
55-
cpu = cpumask_any_but(mask, exclude_cpu);
56-
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/* Only continue if tick_nohz_full_mask has been initialized. */
58-
if (!tick_nohz_full_enabled())
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return cpu;
60-
61-
/* If the CPU picked isn't marked nohz_full nothing more needs doing. */
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if (cpu < nr_cpu_ids && !tick_nohz_full_cpu(cpu))
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return cpu;
50+
unsigned int cpu;
6451

6552
/* Try to find a CPU that isn't nohz_full to use in preference */
66-
hk_cpu = cpumask_nth_andnot(0, mask, tick_nohz_full_mask);
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if (hk_cpu == exclude_cpu)
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hk_cpu = cpumask_nth_andnot(1, mask, tick_nohz_full_mask);
69-
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if (hk_cpu < nr_cpu_ids)
71-
cpu = hk_cpu;
53+
if (tick_nohz_full_enabled()) {
54+
cpu = cpumask_any_andnot_but(mask, tick_nohz_full_mask, exclude_cpu);
55+
if (cpu < nr_cpu_ids)
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return cpu;
57+
}
7258

73-
return cpu;
59+
return cpumask_any_but(mask, exclude_cpu);
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}
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7662
struct rdt_fs_context {

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