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x86/intel_rdt: Add cpus_list rdtgroup file 

The resource control filesystem provides only a bitmask based cpus file for
assigning CPUs to a resource group. That's cumbersome with large cpumasks
and non-intuitive when modifying the file from the command line.

Range based cpu lists are commonly used along with bitmask based cpu files
in various subsystems throughout the kernel.

Add 'cpus_list' file which is CPU range based.

  # 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

[ tglx: Massaged changelog and replaced "bitmask lists" by "CPU ranges" ]

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Shaohua Li <shli@fb.com>
Link: http://lkml.kernel.org/r/20170410145232.GF25354@krava
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Jiri Olsa 2017-04-10 16:52:32 +02:00 committed by Thomas Gleixner
parent 17f8ba1dca
commit 4ffa3c977b
3 changed files with 33 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
Documentation/x86/intel_rdt_ui.txt
View File

@ -59,6 +59,9 @@ There are three files associated with each group:
given to the default (root) group. You cannot remove CPUs
from the default group.
"cpus_list": One or more CPU ranges of logical CPUs assigned to this
group. Same rules apply like for the "cpus" file.
"schemata": A list of all the resources available to this group.
Each resource has its own line and format - see below for
details.

5
arch/x86/include/asm/intel_rdt.h
View File

@ -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;
@ -49,6 +52,7 @@ int __init rdtgroup_init(void);
* @name: File name
* @mode: Access mode
* @kf_ops: File operations
* @flags: File specific RFTYPE_FLAGS_* flags
* @seq_show: Show content of the file
* @write: Write to the file
*/
@ -56,6 +60,7 @@ 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);

27
arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
View File

@ -174,6 +174,13 @@ static struct kernfs_ops rdtgroup_kf_single_ops = {
.seq_show = rdtgroup_seqfile_show,
};
static bool is_cpu_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)
{
@ -182,10 +189,12 @@ 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_cpu_list(of) ? "%*pbl\n" : "%*pb\n",
cpumask_pr_args(&rdtgrp->cpu_mask));
} else {
ret = -ENOENT;
}
rdtgroup_kn_unlock(of->kn);
return ret;
@ -252,7 +261,11 @@ static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of,
goto unlock;
}
if (is_cpu_list(of))
ret = cpulist_parse(buf, newmask);
else
ret = cpumask_parse(buf, newmask);
if (ret)
goto unlock;
@ -472,6 +485,14 @@ static struct rftype rdtgroup_base_files[] = {
.write = rdtgroup_cpus_write,
.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,