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Commit f3cbeaca authored by Vikas Shivappa's avatar Vikas Shivappa Committed by Thomas Gleixner
Browse files

x86/intel_rdt/cqm: Add rmdir support 



Resource groups (ctrl_mon and monitor groups) are represented by
directories in resctrl fs. Add support to remove the directories.

When a ctrl_mon directory is removed all the cpus and tasks are assigned
back to the root rdtgroup. When a monitor group is removed the cpus and
tasks are returned to the parent control group.

Signed-off-by: default avatarVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-22-git-send-email-vikas.shivappa@linux.intel.com
parent f9049547

arch/x86/kernel/cpu/intel_rdt_rdtgroup.c

+86 −4
Original line number Diff line number Diff line
@@ -1130,6 +1130,18 @@ static int reset_all_ctrls(struct rdt_resource *r) 
	return 0;

}



static bool is_closid_match(struct task_struct *t, struct rdtgroup *r)

{

	return (rdt_alloc_capable &&

		(r->type == RDTCTRL_GROUP) && (t->closid == r->closid));

}



static bool is_rmid_match(struct task_struct *t, struct rdtgroup *r)

{

	return (rdt_mon_capable &&

		(r->type == RDTMON_GROUP) && (t->rmid == r->mon.rmid));

}



/*

 * Move tasks from one to the other group. If @from is NULL, then all tasks

 * in the systems are moved unconditionally (used for teardown).
@@ -1145,8 +1157,11 @@ static void rdt_move_group_tasks(struct rdtgroup *from, struct rdtgroup *to, 


	read_lock(&tasklist_lock);

	for_each_process_thread(p, t) {

		if (!from || t->closid == from->closid) {

		if (!from || is_closid_match(t, from) ||

		    is_rmid_match(t, from)) {

			t->closid = to->closid;

			t->rmid = to->mon.rmid;



#ifdef CONFIG_SMP

			/*

			 * This is safe on x86 w/o barriers as the ordering
@@ -1165,6 +1180,19 @@ static void rdt_move_group_tasks(struct rdtgroup *from, struct rdtgroup *to, 
	read_unlock(&tasklist_lock);

}



static void free_all_child_rdtgrp(struct rdtgroup *rdtgrp)

{

	struct rdtgroup *sentry, *stmp;

	struct list_head *head;



	head = &rdtgrp->mon.crdtgrp_list;

	list_for_each_entry_safe(sentry, stmp, head, mon.crdtgrp_list) {

		free_rmid(sentry->mon.rmid);

		list_del(&sentry->mon.crdtgrp_list);

		kfree(sentry);

	}

}



/*

 * Forcibly remove all of subdirectories under root.

 */
@@ -1565,6 +1593,44 @@ static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name, 
	return -EPERM;

}



static int rdtgroup_rmdir_mon(struct kernfs_node *kn, struct rdtgroup *rdtgrp,

			      cpumask_var_t tmpmask)

{

	struct rdtgroup *prdtgrp = rdtgrp->mon.parent;

	int cpu;



	/* Give any tasks back to the parent group */

	rdt_move_group_tasks(rdtgrp, prdtgrp, tmpmask);



	/* Update per cpu rmid of the moved CPUs first */

	for_each_cpu(cpu, &rdtgrp->cpu_mask)

		per_cpu(rdt_cpu_default.rmid, cpu) = prdtgrp->mon.rmid;

	/*

	 * Update the MSR on moved CPUs and CPUs which have moved

	 * task running on them.

	 */

	cpumask_or(tmpmask, tmpmask, &rdtgrp->cpu_mask);

	update_closid_rmid(tmpmask, NULL);



	rdtgrp->flags = RDT_DELETED;

	free_rmid(rdtgrp->mon.rmid);



	/*

	 * Remove the rdtgrp from the parent ctrl_mon group's list

	 */

	WARN_ON(list_empty(&prdtgrp->mon.crdtgrp_list));

	list_del(&rdtgrp->mon.crdtgrp_list);



	/*

	 * one extra hold on this, will drop when we kfree(rdtgrp)

	 * in rdtgroup_kn_unlock()

	 */

	kernfs_get(kn);

	kernfs_remove(rdtgrp->kn);



	return 0;

}



static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp,

			       cpumask_var_t tmpmask)

{
@@ -1577,9 +1643,12 @@ static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp, 
	cpumask_or(&rdtgroup_default.cpu_mask,

		   &rdtgroup_default.cpu_mask, &rdtgrp->cpu_mask);



	/* Update per cpu closid of the moved CPUs first */

	for_each_cpu(cpu, &rdtgrp->cpu_mask)

	/* Update per cpu closid and rmid of the moved CPUs first */

	for_each_cpu(cpu, &rdtgrp->cpu_mask) {

		per_cpu(rdt_cpu_default.closid, cpu) = rdtgroup_default.closid;

		per_cpu(rdt_cpu_default.rmid, cpu) = rdtgroup_default.mon.rmid;

	}



	/*

	 * Update the MSR on moved CPUs and CPUs which have moved

	 * task running on them.
@@ -1589,6 +1658,13 @@ static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp, 


	rdtgrp->flags = RDT_DELETED;

	closid_free(rdtgrp->closid);

	free_rmid(rdtgrp->mon.rmid);



	/*

	 * Free all the child monitor group rmids.

	 */

	free_all_child_rdtgrp(rdtgrp);



	list_del(&rdtgrp->rdtgroup_list);



	/*
@@ -1619,10 +1695,16 @@ static int rdtgroup_rmdir(struct kernfs_node *kn) 


	/*

	 * If the rdtgroup is a ctrl_mon group and parent directory

	 * is the root directory, remove the ctrl group.

	 * is the root directory, remove the ctrl_mon group.

	 *

	 * If the rdtgroup is a mon group and parent directory

	 * is a valid "mon_groups" directory, remove the mon group.

	 */

	if (rdtgrp->type == RDTCTRL_GROUP && parent_kn == rdtgroup_default.kn)

		ret = rdtgroup_rmdir_ctrl(kn, rdtgrp, tmpmask);

	else if (rdtgrp->type == RDTMON_GROUP &&

		 is_mon_groups(parent_kn, kn->name))

		ret = rdtgroup_rmdir_mon(kn, rdtgrp, tmpmask);

	else

		ret = -EPERM;