Subsystem housekeeping masks are currently static and can only be set via boot-time parameters (isolcpus, nohz_full, etc.). There is no userspace interface to reconfigure these boundaries at runtime.
Implement the DHEI sysfs interface under /sys/kernel/housekeeping. This enables userspace to independently reconfigure different kernel services' affinities without a reboot. Signed-off-by: Qiliang Yuan <[email protected]> --- kernel/sched/isolation.c | 89 ++++++++++++++++++++++++------------------------ 1 file changed, 45 insertions(+), 44 deletions(-) diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index 685cc0df1bd9f..1c867784d155b 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -8,7 +8,12 @@ * */ #include <linux/sched/isolation.h> +#include <linux/capability.h> #include <linux/mutex.h> +#include <linux/kobject.h> +#include <linux/sysfs.h> +#include <linux/slab.h> +#include <linux/ctype.h> #include <linux/notifier.h> #include <linux/topology.h> #include "sched.h" @@ -16,9 +21,17 @@ enum hk_flags { HK_FLAG_DOMAIN = BIT(HK_TYPE_DOMAIN), HK_FLAG_MANAGED_IRQ = BIT(HK_TYPE_MANAGED_IRQ), - HK_FLAG_KERNEL_NOISE = BIT(HK_TYPE_KERNEL_NOISE), + HK_FLAG_TICK = BIT(HK_TYPE_TICK), + HK_FLAG_TIMER = BIT(HK_TYPE_TIMER), + HK_FLAG_RCU = BIT(HK_TYPE_RCU), + HK_FLAG_MISC = BIT(HK_TYPE_MISC), + HK_FLAG_WQ = BIT(HK_TYPE_WQ), + HK_FLAG_KTHREAD = BIT(HK_TYPE_KTHREAD), }; +#define HK_FLAG_KERNEL_NOISE (HK_FLAG_TICK | HK_FLAG_TIMER | HK_FLAG_RCU | \ + HK_FLAG_MISC | HK_FLAG_WQ | HK_FLAG_KTHREAD) + static DEFINE_MUTEX(housekeeping_mutex); static BLOCKING_NOTIFIER_HEAD(housekeeping_notifier_list); DEFINE_STATIC_KEY_FALSE(housekeeping_overridden); @@ -44,6 +57,9 @@ static ssize_t smt_aware_store(struct kobject *kobj, { bool val; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (kstrtobool(buf, &val)) return -EINVAL; @@ -53,7 +69,7 @@ static ssize_t smt_aware_store(struct kobject *kobj, } static struct kobj_attribute smt_aware_attr = - __ATTR(smt_aware_mode, 0644, smt_aware_show, smt_aware_store); + __ATTR(smt_aware_mode, 0600, smt_aware_show, smt_aware_store); bool housekeeping_enabled(enum hk_type type) { @@ -171,6 +187,9 @@ static ssize_t housekeeping_store(struct kobject *kobject, cpumask_var_t new_mask; int err; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) return -ENOMEM; @@ -178,42 +197,26 @@ static ssize_t housekeeping_store(struct kobject *kobject, if (err) goto out_free; - /* Safety check: must have at least one online CPU for housekeeping */ - if (!cpumask_intersects(new_mask, cpu_online_mask)) { + if (cpumask_empty(new_mask) || + !cpumask_intersects(new_mask, cpu_online_mask)) { err = -EINVAL; goto out_free; } - if (housekeeping_smt_aware) { - int cpu, sibling; - cpumask_var_t tmp_mask; + mutex_lock(&housekeeping_mutex); - if (!alloc_cpumask_var(&tmp_mask, GFP_KERNEL)) { - err = -ENOMEM; - goto out_free; - } + if (housekeeping_smt_aware) { + int cpu; - cpumask_copy(tmp_mask, new_mask); - for_each_cpu(cpu, tmp_mask) { - for_each_cpu(sibling, topology_sibling_cpumask(cpu)) { - if (!cpumask_test_cpu(sibling, tmp_mask)) { - /* SMT sibling should stay grouped */ - cpumask_clear_cpu(cpu, new_mask); - break; - } + for_each_cpu(cpu, new_mask) { + if (!cpumask_subset(topology_sibling_cpumask(cpu), + new_mask)) { + err = -EINVAL; + goto out_unlock; } } - free_cpumask_var(tmp_mask); - - /* Re-check after SMT sync */ - if (!cpumask_intersects(new_mask, cpu_online_mask)) { - err = -EINVAL; - goto out_free; - } } - mutex_lock(&housekeeping_mutex); - if (!housekeeping.cpumasks[type]) { if (!alloc_cpumask_var(&housekeeping.cpumasks[type], GFP_KERNEL)) { err = -ENOMEM; @@ -242,7 +245,7 @@ static ssize_t housekeeping_store(struct kobject *kobject, } static struct hk_attribute housekeeping_attrs[HK_TYPE_MAX]; -static struct attribute *housekeeping_attr_ptr[HK_TYPE_MAX + 1]; +static struct attribute *housekeeping_attr_ptr[HK_TYPE_MAX + 2]; static const struct attribute_group housekeeping_attr_group = { .attrs = housekeeping_attr_ptr, @@ -265,28 +268,22 @@ static int __init housekeeping_sysfs_init(void) housekeeping_attrs[i].type = i; sysfs_attr_init(&housekeeping_attrs[i].kattr.attr); housekeeping_attrs[i].kattr.attr.name = hk_type_names[i]; - housekeeping_attrs[i].kattr.attr.mode = 0644; + housekeeping_attrs[i].kattr.attr.mode = 0600; housekeeping_attrs[i].kattr.show = housekeeping_show; housekeeping_attrs[i].kattr.store = housekeeping_store; housekeeping_attr_ptr[j++] = &housekeeping_attrs[i].kattr.attr; } + + housekeeping_attr_ptr[j++] = &smt_aware_attr.attr; housekeeping_attr_ptr[j] = NULL; ret = sysfs_create_group(housekeeping_kobj, &housekeeping_attr_group); - if (ret) - goto err_group; - - ret = sysfs_create_file(housekeeping_kobj, &smt_aware_attr.attr); - if (ret) - goto err_file; + if (ret) { + kobject_put(housekeeping_kobj); + return ret; + } return 0; - -err_file: - sysfs_remove_group(housekeeping_kobj, &housekeeping_attr_group); -err_group: - kobject_put(housekeeping_kobj); - return ret; } late_initcall(housekeeping_sysfs_init); @@ -313,8 +310,12 @@ static void __init housekeeping_setup_type(enum hk_type type, if (!slab_is_available()) gfp = GFP_NOWAIT; - if (!housekeeping.cpumasks[type]) - alloc_cpumask_var(&housekeeping.cpumasks[type], gfp); + if (!housekeeping.cpumasks[type]) { + if (!alloc_cpumask_var(&housekeeping.cpumasks[type], gfp)) { + pr_err("housekeeping: failed to allocate cpumask for type %d\n", type); + return; + } + } cpumask_copy(housekeeping.cpumasks[type], housekeeping_staging); -- 2.43.0
