4 files changed, 122 insertions, 29 deletions

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 03eb90d00af0..89049b343c7a 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -618,7 +618,7 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
 		if (static_branch_unlikely(&rdt_mon_enable_key))
 			rmdir_mondata_subdir_allrdtgrp(r, d->id);
 		list_del(&d->list);
-		if (is_mbm_enabled())
+		if (r->mon_capable && is_mbm_enabled())
 			cancel_delayed_work(&d->mbm_over);
 		if (is_llc_occupancy_enabled() &&  has_busy_rmid(r, d)) {
 			/*
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index e49b77283924..181c992f448c 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -57,6 +57,7 @@ static inline struct rdt_fs_context *rdt_fc2context(struct fs_context *fc)
 }
 
 DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
+DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
 
 /**
  * struct mon_evt - Entry in the event list of a resource
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 397206f23d14..773124b0e18a 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -514,7 +514,7 @@ void mbm_handle_overflow(struct work_struct *work)
 
 	mutex_lock(&rdtgroup_mutex);
 
-	if (!static_branch_likely(&rdt_enable_key))
+	if (!static_branch_likely(&rdt_mon_enable_key))
 		goto out_unlock;
 
 	d = get_domain_from_cpu(cpu, &rdt_resources_all[RDT_RESOURCE_L3]);
@@ -543,7 +543,7 @@ void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms)
 	unsigned long delay = msecs_to_jiffies(delay_ms);
 	int cpu;
 
-	if (!static_branch_likely(&rdt_enable_key))
+	if (!static_branch_likely(&rdt_mon_enable_key))
 		return;
 	cpu = cpumask_any(&dom->cpu_mask);
 	dom->mbm_work_cpu = cpu;
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 2e3b06d6bbc6..8ca5e510f3ce 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -532,11 +532,15 @@ static void move_myself(struct callback_head *head)
 		kfree(rdtgrp);
 	}
 
+	if (unlikely(current->flags & PF_EXITING))
+		goto out;
+
 	preempt_disable();
 	/* update PQR_ASSOC MSR to make resource group go into effect */
 	resctrl_sched_in();
 	preempt_enable();
 
+out:
 	kfree(callback);
 }
 
@@ -725,6 +729,92 @@ static int rdtgroup_tasks_show(struct kernfs_open_file *of,
 	return ret;
 }
 
+#ifdef CONFIG_PROC_CPU_RESCTRL
+
+/*
+ * A task can only be part of one resctrl control group and of one monitor
+ * group which is associated to that control group.
+ *
+ * 1)   res:
+ *      mon:
+ *
+ *    resctrl is not available.
+ *
+ * 2)   res:/
+ *      mon:
+ *
+ *    Task is part of the root resctrl control group, and it is not associated
+ *    to any monitor group.
+ *
+ * 3)  res:/
+ *     mon:mon0
+ *
+ *    Task is part of the root resctrl control group and monitor group mon0.
+ *
+ * 4)  res:group0
+ *     mon:
+ *
+ *    Task is part of resctrl control group group0, and it is not associated
+ *    to any monitor group.
+ *
+ * 5) res:group0
+ *    mon:mon1
+ *
+ *    Task is part of resctrl control group group0 and monitor group mon1.
+ */
+int proc_resctrl_show(struct seq_file *s, struct pid_namespace *ns,
+		      struct pid *pid, struct task_struct *tsk)
+{
+	struct rdtgroup *rdtg;
+	int ret = 0;
+
+	mutex_lock(&rdtgroup_mutex);
+
+	/* Return empty if resctrl has not been mounted. */
+	if (!static_branch_unlikely(&rdt_enable_key)) {
+		seq_puts(s, "res:\nmon:\n");
+		goto unlock;
+	}
+
+	list_for_each_entry(rdtg, &rdt_all_groups, rdtgroup_list) {
+		struct rdtgroup *crg;
+
+		/*
+		 * Task information is only relevant for shareable
+		 * and exclusive groups.
+		 */
+		if (rdtg->mode != RDT_MODE_SHAREABLE &&
+		    rdtg->mode != RDT_MODE_EXCLUSIVE)
+			continue;
+
+		if (rdtg->closid != tsk->closid)
+			continue;
+
+		seq_printf(s, "res:%s%s\n", (rdtg == &rdtgroup_default) ? "/" : "",
+			   rdtg->kn->name);
+		seq_puts(s, "mon:");
+		list_for_each_entry(crg, &rdtg->mon.crdtgrp_list,
+				    mon.crdtgrp_list) {
+			if (tsk->rmid != crg->mon.rmid)
+				continue;
+			seq_printf(s, "%s", crg->kn->name);
+			break;
+		}
+		seq_putc(s, '\n');
+		goto unlock;
+	}
+	/*
+	 * The above search should succeed. Otherwise return
+	 * with an error.
+	 */
+	ret = -ENOENT;
+unlock:
+	mutex_unlock(&rdtgroup_mutex);
+
+	return ret;
+}
+#endif
+
 static int rdt_last_cmd_status_show(struct kernfs_open_file *of,
 				    struct seq_file *seq, void *v)
 {
@@ -1741,9 +1831,6 @@ static int set_cache_qos_cfg(int level, bool enable)
 	struct rdt_domain *d;
 	int cpu;
 
-	if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
-		return -ENOMEM;
-
 	if (level == RDT_RESOURCE_L3)
 		update = l3_qos_cfg_update;
 	else if (level == RDT_RESOURCE_L2)
@@ -1751,6 +1838,9 @@ static int set_cache_qos_cfg(int level, bool enable)
 	else
 		return -EINVAL;
 
+	if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
+		return -ENOMEM;
+
 	r_l = &rdt_resources_all[level];
 	list_for_each_entry(d, &r_l->domains, list) {
 		/* Pick one CPU from each domain instance to update MSR */
@@ -1970,7 +2060,7 @@ static int rdt_get_tree(struct fs_context *fc)
 
 	if (rdt_mon_capable) {
 		ret = mongroup_create_dir(rdtgroup_default.kn,
-					  NULL, "mon_groups",
+					  &rdtgroup_default, "mon_groups",
 					  &kn_mongrp);
 		if (ret < 0)
 			goto out_info;
@@ -2205,7 +2295,11 @@ static void free_all_child_rdtgrp(struct rdtgroup *rdtgrp)
 	list_for_each_entry_safe(sentry, stmp, head, mon.crdtgrp_list) {
 		free_rmid(sentry->mon.rmid);
 		list_del(&sentry->mon.crdtgrp_list);
-		kfree(sentry);
+
+		if (atomic_read(&sentry->waitcount) != 0)
+			sentry->flags = RDT_DELETED;
+		else
+			kfree(sentry);
 	}
 }
 
@@ -2243,7 +2337,11 @@ static void rmdir_all_sub(void)
 
 		kernfs_remove(rdtgrp->kn);
 		list_del(&rdtgrp->rdtgroup_list);
-		kfree(rdtgrp);
+
+		if (atomic_read(&rdtgrp->waitcount) != 0)
+			rdtgrp->flags = RDT_DELETED;
+		else
+			kfree(rdtgrp);
 	}
 	/* Notify online CPUs to update per cpu storage and PQR_ASSOC MSR */
 	update_closid_rmid(cpu_online_mask, &rdtgroup_default);
@@ -2446,7 +2544,7 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
 	/*
 	 * Create the mon_data directory first.
 	 */
-	ret = mongroup_create_dir(parent_kn, NULL, "mon_data", &kn);
+	ret = mongroup_create_dir(parent_kn, prgrp, "mon_data", &kn);
 	if (ret)
 		return ret;
 
@@ -2636,7 +2734,6 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
 }
 
 static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
-			     struct kernfs_node *prgrp_kn,
 			     const char *name, umode_t mode,
 			     enum rdt_group_type rtype, struct rdtgroup **r)
 {
@@ -2645,7 +2742,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
 	uint files = 0;
 	int ret;
 
-	prdtgrp = rdtgroup_kn_lock_live(prgrp_kn);
+	prdtgrp = rdtgroup_kn_lock_live(parent_kn);
 	if (!prdtgrp) {
 		ret = -ENODEV;
 		goto out_unlock;
@@ -2718,7 +2815,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
 	kernfs_activate(kn);
 
 	/*
-	 * The caller unlocks the prgrp_kn upon success.
+	 * The caller unlocks the parent_kn upon success.
 	 */
 	return 0;
 
@@ -2729,7 +2826,7 @@ out_destroy:
 out_free_rgrp:
 	kfree(rdtgrp);
 out_unlock:
-	rdtgroup_kn_unlock(prgrp_kn);
+	rdtgroup_kn_unlock(parent_kn);
 	return ret;
 }
 
@@ -2746,15 +2843,12 @@ static void mkdir_rdt_prepare_clean(struct rdtgroup *rgrp)
  * to monitor a subset of tasks and cpus in its parent ctrl_mon group.
  */
 static int rdtgroup_mkdir_mon(struct kernfs_node *parent_kn,
-			      struct kernfs_node *prgrp_kn,
-			      const char *name,
-			      umode_t mode)
+			      const char *name, umode_t mode)
 {
 	struct rdtgroup *rdtgrp, *prgrp;
 	int ret;
 
-	ret = mkdir_rdt_prepare(parent_kn, prgrp_kn, name, mode, RDTMON_GROUP,
-				&rdtgrp);
+	ret = mkdir_rdt_prepare(parent_kn, name, mode, RDTMON_GROUP, &rdtgrp);
 	if (ret)
 		return ret;
 
@@ -2767,7 +2861,7 @@ static int rdtgroup_mkdir_mon(struct kernfs_node *parent_kn,
 	 */
 	list_add_tail(&rdtgrp->mon.crdtgrp_list, &prgrp->mon.crdtgrp_list);
 
-	rdtgroup_kn_unlock(prgrp_kn);
+	rdtgroup_kn_unlock(parent_kn);
 	return ret;
 }
 
@@ -2776,7 +2870,6 @@ static int rdtgroup_mkdir_mon(struct kernfs_node *parent_kn,
  * to allocate and monitor resources.
  */
 static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
-				   struct kernfs_node *prgrp_kn,
 				   const char *name, umode_t mode)
 {
 	struct rdtgroup *rdtgrp;
@@ -2784,8 +2877,7 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
 	u32 closid;
 	int ret;
 
-	ret = mkdir_rdt_prepare(parent_kn, prgrp_kn, name, mode, RDTCTRL_GROUP,
-				&rdtgrp);
+	ret = mkdir_rdt_prepare(parent_kn, name, mode, RDTCTRL_GROUP, &rdtgrp);
 	if (ret)
 		return ret;
 
@@ -2810,7 +2902,7 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
 		 * Create an empty mon_groups directory to hold the subset
 		 * of tasks and cpus to monitor.
 		 */
-		ret = mongroup_create_dir(kn, NULL, "mon_groups", NULL);
+		ret = mongroup_create_dir(kn, rdtgrp, "mon_groups", NULL);
 		if (ret) {
 			rdt_last_cmd_puts("kernfs subdir error\n");
 			goto out_del_list;
@@ -2826,7 +2918,7 @@ out_id_free:
 out_common_fail:
 	mkdir_rdt_prepare_clean(rdtgrp);
 out_unlock:
-	rdtgroup_kn_unlock(prgrp_kn);
+	rdtgroup_kn_unlock(parent_kn);
 	return ret;
 }
 
@@ -2859,14 +2951,14 @@ static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
 	 * subdirectory
 	 */
 	if (rdt_alloc_capable && parent_kn == rdtgroup_default.kn)
-		return rdtgroup_mkdir_ctrl_mon(parent_kn, parent_kn, name, mode);
+		return rdtgroup_mkdir_ctrl_mon(parent_kn, name, mode);
 
 	/*
 	 * If RDT monitoring is supported and the parent directory is a valid
 	 * "mon_groups" directory, add a monitoring subdirectory.
 	 */
 	if (rdt_mon_capable && is_mon_groups(parent_kn, name))
-		return rdtgroup_mkdir_mon(parent_kn, parent_kn->parent, name, mode);
+		return rdtgroup_mkdir_mon(parent_kn, name, mode);
 
 	return -EPERM;
 }
@@ -2952,13 +3044,13 @@ static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp,
 	closid_free(rdtgrp->closid);
 	free_rmid(rdtgrp->mon.rmid);
 
+	rdtgroup_ctrl_remove(kn, rdtgrp);
+
 	/*
 	 * Free all the child monitor group rmids.
 	 */
 	free_all_child_rdtgrp(rdtgrp);
 
-	rdtgroup_ctrl_remove(kn, rdtgrp);
-
 	return 0;
 }