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// SPDX-License-Identifier: GPL-2.0-only
/*
* Housekeeping management. Manage the targets for routine code that can run on
* any CPU: unbound workqueues, timers, kthreads and any offloadable work.
*
* Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker
* Copyright (C) 2017-2018 SUSE, Frederic Weisbecker
*
*/
#include "sched.h"
enum hk_flags {
HK_FLAG_TIMER = BIT(HK_TYPE_TIMER),
HK_FLAG_RCU = BIT(HK_TYPE_RCU),
HK_FLAG_MISC = BIT(HK_TYPE_MISC),
HK_FLAG_SCHED = BIT(HK_TYPE_SCHED),
HK_FLAG_TICK = BIT(HK_TYPE_TICK),
HK_FLAG_DOMAIN = BIT(HK_TYPE_DOMAIN),
HK_FLAG_WQ = BIT(HK_TYPE_WQ),
HK_FLAG_MANAGED_IRQ = BIT(HK_TYPE_MANAGED_IRQ),
HK_FLAG_KTHREAD = BIT(HK_TYPE_KTHREAD),
};
DEFINE_STATIC_KEY_FALSE(housekeeping_overridden);
EXPORT_SYMBOL_GPL(housekeeping_overridden);
static cpumask_var_t housekeeping_mask;
static unsigned int housekeeping_flags;
bool housekeeping_enabled(enum hk_type type)
{
return !!(housekeeping_flags & BIT(type));
}
EXPORT_SYMBOL_GPL(housekeeping_enabled);
int housekeeping_any_cpu(enum hk_type type)
{
int cpu;
if (static_branch_unlikely(&housekeeping_overridden)) {
if (housekeeping_flags & BIT(type)) {
cpu = sched_numa_find_closest(housekeeping_mask, smp_processor_id());
if (cpu < nr_cpu_ids)
return cpu;
return cpumask_any_and(housekeeping_mask, cpu_online_mask);
}
}
return smp_processor_id();
}
EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
const struct cpumask *housekeeping_cpumask(enum hk_type type)
{
if (static_branch_unlikely(&housekeeping_overridden))
if (housekeeping_flags & BIT(type))
return housekeeping_mask;
return cpu_possible_mask;
}
EXPORT_SYMBOL_GPL(housekeeping_cpumask);
void housekeeping_affine(struct task_struct *t, enum hk_type type)
{
if (static_branch_unlikely(&housekeeping_overridden))
if (housekeeping_flags & BIT(type))
set_cpus_allowed_ptr(t, housekeeping_mask);
}
EXPORT_SYMBOL_GPL(housekeeping_affine);
bool housekeeping_test_cpu(int cpu, enum hk_type type)
{
if (static_branch_unlikely(&housekeeping_overridden))
if (housekeeping_flags & BIT(type))
return cpumask_test_cpu(cpu, housekeeping_mask);
return true;
}
EXPORT_SYMBOL_GPL(housekeeping_test_cpu);
void __init housekeeping_init(void)
{
if (!housekeeping_flags)
return;
static_branch_enable(&housekeeping_overridden);
if (housekeeping_flags & HK_FLAG_TICK)
sched_tick_offload_init();
/* We need at least one CPU to handle housekeeping work */
WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
}
static int __init housekeeping_setup(char *str, enum hk_flags flags)
{
cpumask_var_t non_housekeeping_mask;
cpumask_var_t tmp;
alloc_bootmem_cpumask_var(&non_housekeeping_mask);
if (cpulist_parse(str, non_housekeeping_mask) < 0) {
pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n");
free_bootmem_cpumask_var(non_housekeeping_mask);
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);
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");
free_bootmem_cpumask_var(tmp);
free_bootmem_cpumask_var(non_housekeeping_mask);
return 0;
}
}
free_bootmem_cpumask_var(tmp);
if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK)) {
if (IS_ENABLED(CONFIG_NO_HZ_FULL)) {
tick_nohz_full_setup(non_housekeeping_mask);
} else {
pr_warn("Housekeeping: nohz unsupported."
" Build with CONFIG_NO_HZ_FULL\n");
free_bootmem_cpumask_var(non_housekeeping_mask);
return 0;
}
}
housekeeping_flags |= flags;
free_bootmem_cpumask_var(non_housekeeping_mask);
return 1;
}
static int __init housekeeping_nohz_full_setup(char *str)
{
unsigned int flags;
flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU |
HK_FLAG_MISC | HK_FLAG_KTHREAD;
return housekeeping_setup(str, flags);
}
__setup("nohz_full=", housekeeping_nohz_full_setup);
static int __init housekeeping_isolcpus_setup(char *str)
{
unsigned int flags = 0;
bool illegal = false;
char *par;
int len;
while (isalpha(*str)) {
if (!strncmp(str, "nohz,", 5)) {
str += 5;
flags |= HK_FLAG_TICK;
continue;
}
if (!strncmp(str, "domain,", 7)) {
str += 7;
flags |= HK_FLAG_DOMAIN;
continue;
}
if (!strncmp(str, "managed_irq,", 12)) {
str += 12;
flags |= HK_FLAG_MANAGED_IRQ;
continue;
}
/*
* Skip unknown sub-parameter and validate that it is not
* containing an invalid character.
*/
for (par = str, len = 0; *str && *str != ','; str++, len++) {
if (!isalpha(*str) && *str != '_')
illegal = true;
}
if (illegal) {
pr_warn("isolcpus: Invalid flag %.*s\n", len, par);
return 0;
}
pr_info("isolcpus: Skipped unknown flag %.*s\n", len, par);
str++;
}
/* Default behaviour for isolcpus without flags */
if (!flags)
flags |= HK_FLAG_DOMAIN;
return housekeeping_setup(str, flags);
}
__setup("isolcpus=", housekeeping_isolcpus_setup);
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