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Commit a9fcf862 authored by Vikas Shivappa's avatar Vikas Shivappa Committed by Thomas Gleixner
Browse files

x86/intel_rdt/cqm: Add cpus file support 



The cpus file is extended to support resource monitoring. This is used
to over-ride the RMID of the default group when running on specific
CPUs. It works similar to the resource control. The "cpus" and
"cpus_list" file is present in default group, ctrl_mon groups and
monitor groups.

Each "cpus" file or cpu_list file reads a cpumask or list showing which
CPUs belong to the resource group. By default all online cpus belong to
the default root group. A CPU can be present in one "ctrl_mon" and one
"monitor" group simultaneously. They can be added to a resource group by
writing the CPU to the file. When a CPU is added to a ctrl_mon group it
is automatically removed from the previous ctrl_mon group. A CPU can be
added to a monitor group only if it is present in the parent ctrl_mon
group and when a CPU is added to a monitor group, it is automatically
removed from the previous monitor group. When CPUs go offline, they are
automatically removed from the ctrl_mon and monitor groups.

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/1501017287-28083-18-git-send-email-vikas.shivappa@linux.intel.com
parent b09d981b

arch/x86/kernel/cpu/intel_rdt_rdtgroup.c

+93 −17
Original line number Diff line number Diff line
@@ -181,15 +181,17 @@ static int rdtgroup_cpus_show(struct kernfs_open_file *of, 
/*

 * This is safe against intel_rdt_sched_in() called from __switch_to()

 * because __switch_to() is executed with interrupts disabled. A local call

 * from update_closid() is proteced against __switch_to() because

 * from update_closid_rmid() is proteced against __switch_to() because

 * preemption is disabled.

 */

static void update_cpu_closid(void *info)

static void update_cpu_closid_rmid(void *info)

{

	struct rdtgroup *r = info;



	if (r)

	if (r) {

		this_cpu_write(rdt_cpu_default.closid, r->closid);

		this_cpu_write(rdt_cpu_default.rmid, r->mon.rmid);

	}



	/*

	 * We cannot unconditionally write the MSR because the current
@@ -205,20 +207,72 @@ static void update_cpu_closid(void *info) 
 * Per task closids/rmids must have been set up before calling this function.

 */

static void

update_closid(const struct cpumask *cpu_mask, struct rdtgroup *r)

update_closid_rmid(const struct cpumask *cpu_mask, struct rdtgroup *r)

{

	int cpu = get_cpu();



	if (cpumask_test_cpu(cpu, cpu_mask))

		update_cpu_closid(r);

	smp_call_function_many(cpu_mask, update_cpu_closid, r, 1);

		update_cpu_closid_rmid(r);

	smp_call_function_many(cpu_mask, update_cpu_closid_rmid, r, 1);

	put_cpu();

}



static int cpus_ctrl_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask,

static int cpus_mon_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask,

			  cpumask_var_t tmpmask)

{

	struct rdtgroup *r;

	struct rdtgroup *prgrp = rdtgrp->mon.parent, *crgrp;

	struct list_head *head;



	/* Check whether cpus belong to parent ctrl group */

	cpumask_andnot(tmpmask, newmask, &prgrp->cpu_mask);

	if (cpumask_weight(tmpmask))

		return -EINVAL;



	/* Check whether cpus are dropped from this group */

	cpumask_andnot(tmpmask, &rdtgrp->cpu_mask, newmask);

	if (cpumask_weight(tmpmask)) {

		/* Give any dropped cpus to parent rdtgroup */

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

		update_closid_rmid(tmpmask, prgrp);

	}



	/*

	 * If we added cpus, remove them from previous group that owned them

	 * and update per-cpu rmid

	 */

	cpumask_andnot(tmpmask, newmask, &rdtgrp->cpu_mask);

	if (cpumask_weight(tmpmask)) {

		head = &prgrp->mon.crdtgrp_list;

		list_for_each_entry(crgrp, head, mon.crdtgrp_list) {

			if (crgrp == rdtgrp)

				continue;

			cpumask_andnot(&crgrp->cpu_mask, &crgrp->cpu_mask,

				       tmpmask);

		}

		update_closid_rmid(tmpmask, rdtgrp);

	}



	/* Done pushing/pulling - update this group with new mask */

	cpumask_copy(&rdtgrp->cpu_mask, newmask);



	return 0;

}



static void cpumask_rdtgrp_clear(struct rdtgroup *r, struct cpumask *m)

{

	struct rdtgroup *crgrp;



	cpumask_andnot(&r->cpu_mask, &r->cpu_mask, m);

	/* update the child mon group masks as well*/

	list_for_each_entry(crgrp, &r->mon.crdtgrp_list, mon.crdtgrp_list)

		cpumask_and(&crgrp->cpu_mask, &r->cpu_mask, &crgrp->cpu_mask);

}



static int cpus_ctrl_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask,

			   cpumask_var_t tmpmask, cpumask_var_t tmpmask1)

{

	struct rdtgroup *r, *crgrp;

	struct list_head *head;



	/* Check whether cpus are dropped from this group */

	cpumask_andnot(tmpmask, &rdtgrp->cpu_mask, newmask);
@@ -230,33 +284,47 @@ static int cpus_ctrl_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask, 
		/* Give any dropped cpus to rdtgroup_default */

		cpumask_or(&rdtgroup_default.cpu_mask,

			   &rdtgroup_default.cpu_mask, tmpmask);

		update_closid(tmpmask, &rdtgroup_default);

		update_closid_rmid(tmpmask, &rdtgroup_default);

	}



	/*

	 * If we added cpus, remove them from previous group that owned them

	 * and update per-cpu closid

	 * If we added cpus, remove them from previous group and

	 * the prev group's child groups that owned them

	 * and update per-cpu closid/rmid.

	 */

	cpumask_andnot(tmpmask, newmask, &rdtgrp->cpu_mask);

	if (cpumask_weight(tmpmask)) {

		list_for_each_entry(r, &rdt_all_groups, rdtgroup_list) {

			if (r == rdtgrp)

				continue;

			cpumask_andnot(&r->cpu_mask, &r->cpu_mask, tmpmask);

			cpumask_and(tmpmask1, &r->cpu_mask, tmpmask);

			if (cpumask_weight(tmpmask1))

				cpumask_rdtgrp_clear(r, tmpmask1);

		}

		update_closid(tmpmask, rdtgrp);

		update_closid_rmid(tmpmask, rdtgrp);

	}



	/* Done pushing/pulling - update this group with new mask */

	cpumask_copy(&rdtgrp->cpu_mask, newmask);



	/*

	 * Clear child mon group masks since there is a new parent mask

	 * now and update the rmid for the cpus the child lost.

	 */

	head = &rdtgrp->mon.crdtgrp_list;

	list_for_each_entry(crgrp, head, mon.crdtgrp_list) {

		cpumask_and(tmpmask, &rdtgrp->cpu_mask, &crgrp->cpu_mask);

		update_closid_rmid(tmpmask, rdtgrp);

		cpumask_clear(&crgrp->cpu_mask);

	}



	return 0;

}



static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of,

				   char *buf, size_t nbytes, loff_t off)

{

	cpumask_var_t tmpmask, newmask;

	cpumask_var_t tmpmask, newmask, tmpmask1;

	struct rdtgroup *rdtgrp;

	int ret;
@@ -269,6 +337,11 @@ static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of, 
		free_cpumask_var(tmpmask);

		return -ENOMEM;

	}

	if (!zalloc_cpumask_var(&tmpmask1, GFP_KERNEL)) {

		free_cpumask_var(tmpmask);

		free_cpumask_var(newmask);

		return -ENOMEM;

	}



	rdtgrp = rdtgroup_kn_lock_live(of->kn);

	if (!rdtgrp) {
@@ -292,7 +365,9 @@ static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of, 
	}



	if (rdtgrp->type == RDTCTRL_GROUP)

		ret = cpus_ctrl_write(rdtgrp, newmask, tmpmask);

		ret = cpus_ctrl_write(rdtgrp, newmask, tmpmask, tmpmask1);

	else if (rdtgrp->type == RDTMON_GROUP)

		ret = cpus_mon_write(rdtgrp, newmask, tmpmask);

	else

		ret = -EINVAL;
@@ -300,6 +375,7 @@ static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of, 
	rdtgroup_kn_unlock(of->kn);

	free_cpumask_var(tmpmask);

	free_cpumask_var(newmask);

	free_cpumask_var(tmpmask1);



	return ret ?: nbytes;

}
@@ -1113,7 +1189,7 @@ static void rmdir_all_sub(void) 
	}

	/* Notify online CPUs to update per cpu storage and PQR_ASSOC MSR */

	get_online_cpus();

	update_closid(cpu_online_mask, &rdtgroup_default);

	update_closid_rmid(cpu_online_mask, &rdtgroup_default);

	put_online_cpus();



	kernfs_remove(kn_info);
@@ -1374,7 +1450,7 @@ static int rdtgroup_rmdir(struct kernfs_node *kn) 
	 * task running on them.

	 */

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

	update_closid(tmpmask, NULL);

	update_closid_rmid(tmpmask, NULL);



	rdtgrp->flags = RDT_DELETED;

	closid_free(rdtgrp->closid);