From: Tony Luck <tony.l...@intel.com>
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: Tony Luck <tony.l...@intel.com>
Signed-off-by: Fenghua Yu <fenghua...@intel.com>
---
arch/x86/include/asm/intel_rdt.h | 5 ++
arch/x86/kernel/cpu/intel_rdt.c | 23 +++++-
arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 131 ++++++++++++++++++++++++++++++-
3 files changed, 154 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/intel_rdt.h b/arch/x86/include/asm/intel_rdt.h
index a6c7d94..3e8450f 100644
--- a/arch/x86/include/asm/intel_rdt.h
+++ b/arch/x86/include/asm/intel_rdt.h
@@ -12,13 +12,16 @@
* @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;
};
@@ -160,6 +163,8 @@ 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);
diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index 63a0045..9e1f901 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -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;
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 6ff35786..931b406 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -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)
{
@@ -579,6 +685,11 @@ 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;
@@ -599,7 +710,7 @@ 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) {
@@ -607,6 +718,12 @@ 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);
@@ -630,6 +747,8 @@ 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);
@@ -641,12 +760,20 @@ 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;
}
/*
--
2.5.0
