156 lines
4.0 KiB
C
156 lines
4.0 KiB
C
/*
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* Housekeeping management. Manage the targets for routine code that can run on
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* any CPU: unbound workqueues, timers, kthreads and any offloadable work.
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*
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* Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker
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*
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*/
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#include <linux/sched/isolation.h>
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#include <linux/tick.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/static_key.h>
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#include <linux/ctype.h>
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DEFINE_STATIC_KEY_FALSE(housekeeping_overriden);
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EXPORT_SYMBOL_GPL(housekeeping_overriden);
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static cpumask_var_t housekeeping_mask;
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static unsigned int housekeeping_flags;
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int housekeeping_any_cpu(enum hk_flags flags)
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{
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if (static_branch_unlikely(&housekeeping_overriden))
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if (housekeeping_flags & flags)
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return cpumask_any_and(housekeeping_mask, cpu_online_mask);
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return smp_processor_id();
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}
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EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
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const struct cpumask *housekeeping_cpumask(enum hk_flags flags)
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{
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if (static_branch_unlikely(&housekeeping_overriden))
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if (housekeeping_flags & flags)
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return housekeeping_mask;
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return cpu_possible_mask;
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}
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EXPORT_SYMBOL_GPL(housekeeping_cpumask);
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void housekeeping_affine(struct task_struct *t, enum hk_flags flags)
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{
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if (static_branch_unlikely(&housekeeping_overriden))
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if (housekeeping_flags & flags)
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set_cpus_allowed_ptr(t, housekeeping_mask);
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}
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EXPORT_SYMBOL_GPL(housekeeping_affine);
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bool housekeeping_test_cpu(int cpu, enum hk_flags flags)
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{
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if (static_branch_unlikely(&housekeeping_overriden))
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if (housekeeping_flags & flags)
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return cpumask_test_cpu(cpu, housekeeping_mask);
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return true;
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}
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EXPORT_SYMBOL_GPL(housekeeping_test_cpu);
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void __init housekeeping_init(void)
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{
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if (!housekeeping_flags)
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return;
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static_branch_enable(&housekeeping_overriden);
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/* We need at least one CPU to handle housekeeping work */
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WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
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}
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static int __init housekeeping_setup(char *str, enum hk_flags flags)
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{
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cpumask_var_t non_housekeeping_mask;
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int err;
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alloc_bootmem_cpumask_var(&non_housekeeping_mask);
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err = cpulist_parse(str, non_housekeeping_mask);
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if (err < 0 || cpumask_last(non_housekeeping_mask) >= nr_cpu_ids) {
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pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n");
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free_bootmem_cpumask_var(non_housekeeping_mask);
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return 0;
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}
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if (!housekeeping_flags) {
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alloc_bootmem_cpumask_var(&housekeeping_mask);
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cpumask_andnot(housekeeping_mask,
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cpu_possible_mask, non_housekeeping_mask);
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if (cpumask_empty(housekeeping_mask))
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cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
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} else {
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cpumask_var_t tmp;
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alloc_bootmem_cpumask_var(&tmp);
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cpumask_andnot(tmp, cpu_possible_mask, non_housekeeping_mask);
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if (!cpumask_equal(tmp, housekeeping_mask)) {
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pr_warn("Housekeeping: nohz_full= must match isolcpus=\n");
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free_bootmem_cpumask_var(tmp);
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free_bootmem_cpumask_var(non_housekeeping_mask);
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return 0;
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}
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free_bootmem_cpumask_var(tmp);
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}
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if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK)) {
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if (IS_ENABLED(CONFIG_NO_HZ_FULL)) {
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tick_nohz_full_setup(non_housekeeping_mask);
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} else {
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pr_warn("Housekeeping: nohz unsupported."
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" Build with CONFIG_NO_HZ_FULL\n");
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free_bootmem_cpumask_var(non_housekeeping_mask);
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return 0;
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}
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}
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housekeeping_flags |= flags;
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free_bootmem_cpumask_var(non_housekeeping_mask);
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return 1;
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}
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static int __init housekeeping_nohz_full_setup(char *str)
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{
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unsigned int flags;
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flags = HK_FLAG_TICK | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC;
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return housekeeping_setup(str, flags);
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}
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__setup("nohz_full=", housekeeping_nohz_full_setup);
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static int __init housekeeping_isolcpus_setup(char *str)
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{
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unsigned int flags = 0;
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while (isalpha(*str)) {
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if (!strncmp(str, "nohz,", 5)) {
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str += 5;
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flags |= HK_FLAG_TICK;
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continue;
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}
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if (!strncmp(str, "domain,", 7)) {
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str += 7;
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flags |= HK_FLAG_DOMAIN;
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continue;
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}
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pr_warn("isolcpus: Error, unknown flag\n");
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return 0;
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}
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/* Default behaviour for isolcpus without flags */
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if (!flags)
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flags |= HK_FLAG_DOMAIN;
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return housekeeping_setup(str, flags);
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}
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__setup("isolcpus=", housekeeping_isolcpus_setup);
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