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Commit 12e0110c authored by Tony Luck's avatar Tony Luck Committed by Thomas Gleixner
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x86/intel_rdt: Add cpus file 



Now we populate each directory with a read/write (mode 0644) file
named "cpus". This is used to over-ride the resources available
to processes in the default resource group when running on specific
CPUs.  Each "cpus" file reads as a cpumask showing which CPUs belong
to this resource group. Initially all online CPUs are assigned to
the default group. They can be added to other groups by writing a
cpumask to the "cpus" file in the directory for the resource group
(which will remove them from the previous group to which they were
assigned). CPU online/offline operations will delete CPUs that go
offline from whatever group they are in and add new CPUs to the
default group.

If there are CPUs assigned to a group when the directory is removed,
they are returned to the default group.

Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Shaohua Li" <shli@fb.com>
Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: "Stephane Eranian" <eranian@google.com>
Cc: "Dave Hansen" <dave.hansen@intel.com>
Cc: "David Carrillo-Cisneros" <davidcc@google.com>
Cc: "Nilay Vaish" <nilayvaish@gmail.com>
Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com>
Cc: "Ingo Molnar" <mingo@elte.hu>
Cc: "Borislav Petkov" <bp@suse.de>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>
Link: http://lkml.kernel.org/r/1477692289-37412-7-git-send-email-fenghua.yu@intel.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 60cf5e10

arch/x86/include/asm/intel_rdt.h

+5 −0
Original line number Diff line number Diff line
@@ -14,13 +14,16 @@ 
 * @kn:				kernfs node

 * @rdtgroup_list:		linked list for all rdtgroups

 * @closid:			closid for this rdtgroup

 * @cpu_mask:			CPUs assigned to this rdtgroup

 * @flags:			status bits

 * @waitcount:			how many cpus expect to find this

 *				group when they acquire rdtgroup_mutex

 */

struct rdtgroup {

	struct kernfs_node	*kn;

	struct list_head	rdtgroup_list;

	int			closid;

	struct cpumask		cpu_mask;

	int			flags;

	atomic_t		waitcount;

};
@@ -162,6 +165,8 @@ union cpuid_0x10_1_edx { 
	unsigned int full;

};



DECLARE_PER_CPU_READ_MOSTLY(int, cpu_closid);



void rdt_cbm_update(void *arg);

struct rdtgroup *rdtgroup_kn_lock_live(struct kernfs_node *kn);

void rdtgroup_kn_unlock(struct kernfs_node *kn);

arch/x86/kernel/cpu/intel_rdt.c

+20 −3
Original line number Diff line number Diff line
@@ -36,6 +36,8 @@ 
/* Mutex to protect rdtgroup access. */

DEFINE_MUTEX(rdtgroup_mutex);



DEFINE_PER_CPU_READ_MOSTLY(int, cpu_closid);



#define domain_init(id) LIST_HEAD_INIT(rdt_resources_all[id].domains)



struct rdt_resource rdt_resources_all[] = {
@@ -331,16 +333,25 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r) 
	}

}



static int intel_rdt_online_cpu(unsigned int cpu)

static void clear_closid(int cpu)

{

	struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);



	per_cpu(cpu_closid, cpu) = 0;

	state->closid = 0;

	wrmsr(MSR_IA32_PQR_ASSOC, state->rmid, 0);

}



static int intel_rdt_online_cpu(unsigned int cpu)

{

	struct rdt_resource *r;



	mutex_lock(&rdtgroup_mutex);

	for_each_capable_rdt_resource(r)

		domain_add_cpu(cpu, r);

	state->closid = 0;

	wrmsr(MSR_IA32_PQR_ASSOC, state->rmid, 0);

	/* The cpu is set in default rdtgroup after online. */

	cpumask_set_cpu(cpu, &rdtgroup_default.cpu_mask);

	clear_closid(cpu);

	mutex_unlock(&rdtgroup_mutex);



	return 0;
@@ -348,11 +359,17 @@ static int intel_rdt_online_cpu(unsigned int cpu) 


static int intel_rdt_offline_cpu(unsigned int cpu)

{

	struct rdtgroup *rdtgrp;

	struct rdt_resource *r;



	mutex_lock(&rdtgroup_mutex);

	for_each_capable_rdt_resource(r)

		domain_remove_cpu(cpu, r);

	list_for_each_entry(rdtgrp, &rdt_all_groups, rdtgroup_list) {

		if (cpumask_test_and_clear_cpu(cpu, &rdtgrp->cpu_mask))

			break;

	}

	clear_closid(cpu);

	mutex_unlock(&rdtgroup_mutex);



	return 0;

arch/x86/kernel/cpu/intel_rdt_rdtgroup.c

+129 −2
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 


#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt



#include <linux/cpu.h>

#include <linux/fs.h>

#include <linux/sysfs.h>

#include <linux/kernfs.h>
@@ -172,6 +173,111 @@ static struct kernfs_ops rdtgroup_kf_single_ops = { 
	.seq_show		= rdtgroup_seqfile_show,

};



static int rdtgroup_cpus_show(struct kernfs_open_file *of,

			      struct seq_file *s, void *v)

{

	struct rdtgroup *rdtgrp;

	int ret = 0;



	rdtgrp = rdtgroup_kn_lock_live(of->kn);



	if (rdtgrp)

		seq_printf(s, "%*pb\n", cpumask_pr_args(&rdtgrp->cpu_mask));

	else

		ret = -ENOENT;

	rdtgroup_kn_unlock(of->kn);



	return ret;

}



static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of,

				   char *buf, size_t nbytes, loff_t off)

{

	cpumask_var_t tmpmask, newmask;

	struct rdtgroup *rdtgrp, *r;

	int ret, cpu;



	if (!buf)

		return -EINVAL;



	if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))

		return -ENOMEM;

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

		free_cpumask_var(tmpmask);

		return -ENOMEM;

	}

	rdtgrp = rdtgroup_kn_lock_live(of->kn);

	if (!rdtgrp) {

		ret = -ENOENT;

		goto unlock;

	}



	ret = cpumask_parse(buf, newmask);

	if (ret)

		goto unlock;



	get_online_cpus();

	/* check that user didn't specify any offline cpus */

	cpumask_andnot(tmpmask, newmask, cpu_online_mask);

	if (cpumask_weight(tmpmask)) {

		ret = -EINVAL;

		goto end;

	}



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

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

	if (cpumask_weight(tmpmask)) {

		/* Can't drop from default group */

		if (rdtgrp == &rdtgroup_default) {

			ret = -EINVAL;

			goto end;

		}

		/* Give any dropped cpus to rdtgroup_default */

		cpumask_or(&rdtgroup_default.cpu_mask,

			   &rdtgroup_default.cpu_mask, tmpmask);

		for_each_cpu(cpu, tmpmask)

			per_cpu(cpu_closid, cpu) = 0;

	}



	/*

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

	 * and update per-cpu closid

	 */

	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);

		}

		for_each_cpu(cpu, tmpmask)

			per_cpu(cpu_closid, cpu) = rdtgrp->closid;

	}



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

	cpumask_copy(&rdtgrp->cpu_mask, newmask);



end:

	put_online_cpus();

unlock:

	rdtgroup_kn_unlock(of->kn);

	free_cpumask_var(tmpmask);

	free_cpumask_var(newmask);



	return ret ?: nbytes;

}



/* Files in each rdtgroup */

static struct rftype rdtgroup_base_files[] = {

	{

		.name		= "cpus",

		.mode		= 0644,

		.kf_ops		= &rdtgroup_kf_single_ops,

		.write		= rdtgroup_cpus_write,

		.seq_show	= rdtgroup_cpus_show,

	},

};



static int rdt_num_closids_show(struct kernfs_open_file *of,

				struct seq_file *seq, void *v)

{
@@ -582,6 +688,11 @@ static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name, 
	if (ret)

		goto out_destroy;



	ret = rdtgroup_add_files(kn, rdtgroup_base_files,

				 ARRAY_SIZE(rdtgroup_base_files));

	if (ret)

		goto out_destroy;



	kernfs_activate(kn);



	ret = 0;
@@ -602,7 +713,7 @@ static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name, 
static int rdtgroup_rmdir(struct kernfs_node *kn)

{

	struct rdtgroup *rdtgrp;

	int ret = 0;

	int cpu, ret = 0;



	rdtgrp = rdtgroup_kn_lock_live(kn);

	if (!rdtgrp) {
@@ -610,6 +721,12 @@ static int rdtgroup_rmdir(struct kernfs_node *kn) 
		return -ENOENT;

	}



	/* Give any CPUs back to the default group */

	cpumask_or(&rdtgroup_default.cpu_mask,

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

	for_each_cpu(cpu, &rdtgrp->cpu_mask)

		per_cpu(cpu_closid, cpu) = 0;



	rdtgrp->flags = RDT_DELETED;

	closid_free(rdtgrp->closid);

	list_del(&rdtgrp->rdtgroup_list);
@@ -633,6 +750,8 @@ static struct kernfs_syscall_ops rdtgroup_kf_syscall_ops = { 


static int __init rdtgroup_setup_root(void)

{

	int ret;



	rdt_root = kernfs_create_root(&rdtgroup_kf_syscall_ops,

				      KERNFS_ROOT_CREATE_DEACTIVATED,

				      &rdtgroup_default);
@@ -644,12 +763,20 @@ static int __init rdtgroup_setup_root(void) 
	rdtgroup_default.closid = 0;

	list_add(&rdtgroup_default.rdtgroup_list, &rdt_all_groups);



	ret = rdtgroup_add_files(rdt_root->kn, rdtgroup_base_files,

				 ARRAY_SIZE(rdtgroup_base_files));

	if (ret) {

		kernfs_destroy_root(rdt_root);

		goto out;

	}



	rdtgroup_default.kn = rdt_root->kn;

	kernfs_activate(rdtgroup_default.kn);



out:

	mutex_unlock(&rdtgroup_mutex);



	return 0;

	return ret;

}



/*