[PATCHv2] x86/intel_rdt: Add cpus_list rdtgroup file

[Jiri Olsa]

On Fri, Mar 31, 2017 at 05:55:12PM +0200, Jiri Olsa wrote:
> On Fri, Mar 31, 2017 at 11:15:22AM +0200, Thomas Gleixner wrote:
> > On Wed, 29 Mar 2017, Fenghua Yu wrote:
> > > >  static int rdtgroup_cpus_show(struct kernfs_open_file *of,
> > > > -                             struct seq_file *s, void *v)
> > > > +                             struct seq_file *s, void *v,
> > > > +                             unsigned long flags)
> > > >  {
> > > > +       const char *fmt = flags & RFTYPE_FLAGS_CPUS_LIST ? "%*pbl\n" : 
> > > > "%*pb\n";
> > > 
> > > Change to:
> > > + const char *fmt = strcmp(of->kn->priv, "cpus") ? "%*pbl\n" : "%*pb\n";
> > 
> > You couldn't come up with a more horrible hack, right?
> > 
> > Jiri was right with adding the flag to the base files, just the propagation
> > through the callbacks sucks. What's wrong with:
> > 
> >     struct rftype *rft = of->kn->priv;
> >     bool list = rtf->flags & RFTYPE_FLAGS_CPUS_LIST;
> 
> ok, I'll post the change

v2 attached

thanks,
jirka

---
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...@intel.com>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Mike Galbraith <efa...@gmx.de>
Cc: Shaohua Li <s...@fb.com>
Signed-off-by: Jiri Olsa <jo...@kernel.org>
---
 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