lkml.org 
[lkml]   [2023]   [Jan]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[RFC PATCH 1/3] x86/resctrl: Add multiple tasks to the resctrl group at once
From
Date
Right now, the resctrl task assignment for the MONITOR or CONTROL group
needs to be one at a time. For example:
$mount -t resctrl resctrl /sys/fs/resctrl/
$mkdir /sys/fs/resctrl/clos1
$echo 123 > /sys/fs/resctrl/clos1/tasks
$echo 456 > /sys/fs/resctrl/clos1/tasks
$echo 789 > /sys/fs/resctrl/clos1/tasks

This is not user-friendly when dealing with hundreds of tasks.

Improve the user experience by supporting the multiple task assignment
in one command with tasks separated by commas. For example:
$echo 123,456,789 > /sys/fs/resctrl/clos1/tasks

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
Documentation/x86/resctrl.rst | 13 ++++++------
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 35 ++++++++++++++++++++++++++------
2 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
index 71a531061e4e..f26e16412bcb 100644
--- a/Documentation/x86/resctrl.rst
+++ b/Documentation/x86/resctrl.rst
@@ -208,12 +208,13 @@ All groups contain the following files:
"tasks":
Reading this file shows the list of all tasks that belong to
this group. Writing a task id to the file will add a task to the
- group. If the group is a CTRL_MON group the task is removed from
- whichever previous CTRL_MON group owned the task and also from
- any MON group that owned the task. If the group is a MON group,
- then the task must already belong to the CTRL_MON parent of this
- group. The task is removed from any previous MON group.
-
+ group. Multiple tasks can be assigned at once with each task
+ separated by commas. If the group is a CTRL_MON group the task
+ is removed from whichever previous CTRL_MON group owned the task
+ and also from any MON group that owned the task. If the group is
+ a MON group, then the task must already belong to the CTRL_MON
+ parent of this group. The task is removed from any previous MON
+ group.

"cpus":
Reading this file shows a bitmask of the logical CPUs owned by
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index e5a48f05e787..344607853f4c 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -686,28 +686,49 @@ static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct rdtgroup *rdtgrp;
+ char *pid_str;
int ret = 0;
pid_t pid;

- if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
+ /* Valid input requires a trailing newline */
+ if (nbytes == 0 || buf[nbytes - 1] != '\n')
return -EINVAL;
+
+ buf[nbytes - 1] = '\0';
+
+ cpus_read_lock();
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (!rdtgrp) {
- rdtgroup_kn_unlock(of->kn);
- return -ENOENT;
+ ret = -ENOENT;
+ goto exit;
+ }
+
+next:
+ if (!buf || buf[0] == '\0')
+ goto exit;
+
+ pid_str = strim(strsep(&buf, ","));
+
+ if (kstrtoint(pid_str, 0, &pid) || pid < 0) {
+ ret = -EINVAL;
+ goto exit;
}
+
rdt_last_cmd_clear();

if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED ||
- rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
- ret = -EINVAL;
+ rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
rdt_last_cmd_puts("Pseudo-locking in progress\n");
- goto unlock;
+ ret = -EINVAL;
+ goto exit;
}

ret = rdtgroup_move_task(pid, rdtgrp, of);

-unlock:
+ goto next;
+
+exit:
+ cpus_read_unlock();
rdtgroup_kn_unlock(of->kn);

return ret ?: nbytes;

\
 
 \ /
  Last update: 2023-03-26 23:26    [W:1.082 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site