[PATCHv3] x86/intel_rdt: Add cpus_list rdtgroup file

From: Jiri Olsa
Date: Mon Apr 10 2017 - 03:40:22 EST


While playing with the resctrl interface I found it much
easier to deal with cpumask list rather than just regular
cpumask.

Adding cpus_list file to provide cpumask list interface
to define group's cpus.

# cd /sys/fs/resctrl/
# echo 1-10 > krava/cpus_list
# cat krava/cpus_list
1-10
# cat krava/cpus
0007fe
# cat cpus
fffff9
# cat cpus_list
0,3-23

Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Shaohua Li <shli@xxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
arch/x86/include/asm/intel_rdt.h | 4 ++++
arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 28 ++++++++++++++++++++++++----
2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/intel_rdt.h b/arch/x86/include/asm/intel_rdt.h
index 3f313991c0b3..a1a6681738a5 100644
--- a/arch/x86/include/asm/intel_rdt.h
+++ b/arch/x86/include/asm/intel_rdt.h
@@ -37,6 +37,9 @@ struct rdtgroup {
/* rdtgroup.flags */
#define RDT_DELETED 1

+/* rftype.flags */
+#define RFTYPE_FLAGS_CPUS_LIST 1
+
/* List of all resource groups */
extern struct list_head rdt_all_groups;

@@ -56,6 +59,7 @@ struct rftype {
char *name;
umode_t mode;
struct kernfs_ops *kf_ops;
+ unsigned long flags;

int (*seq_show)(struct kernfs_open_file *of,
struct seq_file *sf, void *v);
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 9ac2a5cdd9c2..b089d2452f1e 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -174,6 +174,13 @@ static ssize_t rdtgroup_file_write(struct kernfs_open_file *of, char *buf,
.seq_show = rdtgroup_seqfile_show,
};

+static bool is_list(struct kernfs_open_file *of)
+{
+ struct rftype *rft = of->kn->priv;
+
+ return rft->flags & RFTYPE_FLAGS_CPUS_LIST;
+}
+
static int rdtgroup_cpus_show(struct kernfs_open_file *of,
struct seq_file *s, void *v)
{
@@ -182,9 +189,10 @@ static int rdtgroup_cpus_show(struct kernfs_open_file *of,

rdtgrp = rdtgroup_kn_lock_live(of->kn);

- if (rdtgrp)
- seq_printf(s, "%*pb\n", cpumask_pr_args(&rdtgrp->cpu_mask));
- else
+ if (rdtgrp) {
+ seq_printf(s, is_list(of) ? "%*pbl\n" : "%*pb\n",
+ cpumask_pr_args(&rdtgrp->cpu_mask));
+ } else
ret = -ENOENT;
rdtgroup_kn_unlock(of->kn);

@@ -252,7 +260,11 @@ static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of,
goto unlock;
}

- ret = cpumask_parse(buf, newmask);
+ if (is_list(of))
+ ret = cpulist_parse(buf, newmask);
+ else
+ ret = cpumask_parse(buf, newmask);
+
if (ret)
goto unlock;

@@ -473,6 +485,14 @@ static int rdtgroup_tasks_show(struct kernfs_open_file *of,
.seq_show = rdtgroup_cpus_show,
},
{
+ .name = "cpus_list",
+ .mode = 0644,
+ .kf_ops = &rdtgroup_kf_single_ops,
+ .write = rdtgroup_cpus_write,
+ .seq_show = rdtgroup_cpus_show,
+ .flags = RFTYPE_FLAGS_CPUS_LIST,
+ },
+ {
.name = "tasks",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
--
1.8.3.1