In considering changes to a resource group it becomes necessary to know whether tasks have been assigned to the resource group in question.
Introduce a new utility that can be used to check if any tasks have been assigned to a particular resource group. Signed-off-by: Reinette Chatre <reinette.cha...@intel.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: fenghua...@intel.com Cc: tony.l...@intel.com Cc: vikas.shiva...@linux.intel.com Cc: gavin.hind...@intel.com Cc: jithu.jos...@intel.com Cc: dave.han...@intel.com Cc: h...@zytor.com Link: https://lkml.kernel.org/r/9149005d01de4b197bae13a45e6efdb536383ca1.1527593970.git.reinette.cha...@intel.com --- arch/x86/kernel/cpu/intel_rdt.h | 1 + arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 26 ++++++++++++++++++++++++ 2 files changed, 27 insertions(+) diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h index bda87f5ef7bc..10a1539cbec6 100644 --- a/arch/x86/kernel/cpu/intel_rdt.h +++ b/arch/x86/kernel/cpu/intel_rdt.h @@ -480,6 +480,7 @@ bool rdtgroup_cbm_overlaps(struct rdt_resource *r, struct rdt_domain *d, unsigned int rdtgroup_cbm_to_size(struct rdt_resource *r, struct rdt_domain *d, u32 cbm); enum rdtgrp_mode rdtgroup_mode_by_closid(int closid); +int rdtgroup_tasks_assigned(struct rdtgroup *r); struct rdt_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r); int update_domains(struct rdt_resource *r, int closid); void closid_free(int closid); diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index 352475a6cf43..5a2a34d68722 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -564,6 +564,32 @@ static int __rdtgroup_move_task(struct task_struct *tsk, return ret; } +/** + * rdtgroup_tasks_assigned - Test if tasks have been assigned to resource group + * @r: Resource group + * + * Return: 1 if tasks have been assigned to @r, 0 otherwise + */ +int rdtgroup_tasks_assigned(struct rdtgroup *r) +{ + struct task_struct *p, *t; + int ret = 0; + + lockdep_assert_held(&rdtgroup_mutex); + + rcu_read_lock(); + for_each_process_thread(p, t) { + if ((r->type == RDTCTRL_GROUP && t->closid == r->closid) || + (r->type == RDTMON_GROUP && t->rmid == r->mon.rmid)) { + ret = 1; + break; + } + } + rcu_read_unlock(); + + return ret; +} + static int rdtgroup_task_write_permission(struct task_struct *task, struct kernfs_open_file *of) { -- 2.17.0