diff options
| -rw-r--r-- | arch/x86/kernel/cpu/resctrl/monitor.c | 25 | ||||
| -rw-r--r-- | include/linux/resctrl.h | 23 |
2 files changed, 27 insertions, 21 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index fd060ef86f38..e8aeff6673ea 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -277,6 +277,8 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, u64 msr_val, chunks; int ret; + resctrl_arch_rmid_read_context_check(); + if (!cpumask_test_cpu(smp_processor_id(), &d->cpu_mask)) return -EINVAL; @@ -455,8 +457,6 @@ static void add_rmid_to_limbo(struct rmid_entry *entry) { struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl; struct rdt_domain *d; - int cpu, err; - u64 val = 0; u32 idx; lockdep_assert_held(&rdtgroup_mutex); @@ -464,17 +464,7 @@ static void add_rmid_to_limbo(struct rmid_entry *entry) idx = resctrl_arch_rmid_idx_encode(entry->closid, entry->rmid); entry->busy = 0; - cpu = get_cpu(); list_for_each_entry(d, &r->domains, list) { - if (cpumask_test_cpu(cpu, &d->cpu_mask)) { - err = resctrl_arch_rmid_read(r, d, entry->closid, - entry->rmid, - QOS_L3_OCCUP_EVENT_ID, - &val); - if (err || val <= resctrl_rmid_realloc_threshold) - continue; - } - /* * For the first limbo RMID in the domain, * setup up the limbo worker. @@ -484,15 +474,10 @@ static void add_rmid_to_limbo(struct rmid_entry *entry) set_bit(idx, d->rmid_busy_llc); entry->busy++; } - put_cpu(); - if (entry->busy) { - rmid_limbo_count++; - if (IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID)) - closid_num_dirty_rmid[entry->closid]++; - } else { - list_add_tail(&entry->list, &rmid_free_lru); - } + rmid_limbo_count++; + if (IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID)) + closid_num_dirty_rmid[entry->closid]++; } void free_rmid(u32 closid, u32 rmid) diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index bd4ec22b5a96..8649fc84aac2 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -236,7 +236,12 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d); * @eventid: eventid to read, e.g. L3 occupancy. * @val: result of the counter read in bytes. * - * Call from process context on a CPU that belongs to domain @d. + * Some architectures need to sleep when first programming some of the counters. + * (specifically: arm64's MPAM cache occupancy counters can return 'not ready' + * for a short period of time). Call from a non-migrateable process context on + * a CPU that belongs to domain @d. e.g. use smp_call_on_cpu() or + * schedule_work_on(). This function can be called with interrupts masked, + * e.g. using smp_call_function_any(), but may consistently return an error. * * Return: * 0 on success, or -EIO, -EINVAL etc on error. @@ -245,6 +250,22 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, u32 closid, u32 rmid, enum resctrl_event_id eventid, u64 *val); +/** + * resctrl_arch_rmid_read_context_check() - warn about invalid contexts + * + * When built with CONFIG_DEBUG_ATOMIC_SLEEP generate a warning when + * resctrl_arch_rmid_read() is called with preemption disabled. + * + * The contract with resctrl_arch_rmid_read() is that if interrupts + * are unmasked, it can sleep. This allows NOHZ_FULL systems to use an + * IPI, (and fail if the call needed to sleep), while most of the time + * the work is scheduled, allowing the call to sleep. + */ +static inline void resctrl_arch_rmid_read_context_check(void) +{ + if (!irqs_disabled()) + might_sleep(); +} /** * resctrl_arch_reset_rmid() - Reset any private state associated with rmid |