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Commit 9219565a authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Ingo Molnar
Browse files

sched/isolation: Require a present CPU in housekeeping mask 



During housekeeping mask setup, currently a possible CPU is required.
That does not guarantee the CPU would be available at boot time, so
check to ensure that at least one present CPU is in the mask.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lkml.kernel.org/r/20190411033448.20842-5-npiggin@gmail.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 9ca12ac0

kernel/sched/isolation.c

+13 −5
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ void __init housekeeping_init(void) 
static int __init housekeeping_setup(char *str, enum hk_flags flags)

{

	cpumask_var_t non_housekeeping_mask;

	cpumask_var_t tmp;

	int err;



	alloc_bootmem_cpumask_var(&non_housekeeping_mask);
@@ -75,16 +76,23 @@ static int __init housekeeping_setup(char *str, enum hk_flags flags) 
		return 0;

	}



	alloc_bootmem_cpumask_var(&tmp);

	if (!housekeeping_flags) {

		alloc_bootmem_cpumask_var(&housekeeping_mask);

		cpumask_andnot(housekeeping_mask,

			       cpu_possible_mask, non_housekeeping_mask);

		if (cpumask_empty(housekeeping_mask))



		cpumask_andnot(tmp, cpu_present_mask, non_housekeeping_mask);

		if (cpumask_empty(tmp)) {

			pr_warn("Housekeeping: must include one present CPU, "

				"using boot CPU:%d\n", smp_processor_id());

			__cpumask_set_cpu(smp_processor_id(), housekeeping_mask);

			__cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);

		}

	} else {

		cpumask_var_t tmp;



		alloc_bootmem_cpumask_var(&tmp);

		cpumask_andnot(tmp, cpu_present_mask, non_housekeeping_mask);

		if (cpumask_empty(tmp))

			__cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);

		cpumask_andnot(tmp, cpu_possible_mask, non_housekeeping_mask);

		if (!cpumask_equal(tmp, housekeeping_mask)) {

			pr_warn("Housekeeping: nohz_full= must match isolcpus=\n");
@@ -92,8 +100,8 @@ static int __init housekeeping_setup(char *str, enum hk_flags flags) 
			free_bootmem_cpumask_var(non_housekeeping_mask);

			return 0;

		}

		free_bootmem_cpumask_var(tmp);

	}

	free_bootmem_cpumask_var(tmp);



	if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK)) {

		if (IS_ENABLED(CONFIG_NO_HZ_FULL)) {