From 9219565aa89033a9cfdae788c1940473a1253d6c Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Thu, 11 Apr 2019 13:34:47 +1000 Subject: [PATCH] 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: Nicholas Piggin Signed-off-by: Peter Zijlstra (Intel) Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rafael J . Wysocki Cc: Thomas Gleixner Cc: linuxppc-dev@lists.ozlabs.org Link: https://lkml.kernel.org/r/20190411033448.20842-5-npiggin@gmail.com Signed-off-by: Ingo Molnar --- kernel/sched/isolation.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index b02d148e7672..687302051a27 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -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_set_cpu(smp_processor_id(), 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)) { + 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_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)) {