Commit fe2a20ea authored by Babu Moger's avatar Babu Moger Committed by Borislav Petkov (AMD)
Browse files

x86/resctrl: Add multiple tasks to the resctrl group at once 



The resctrl task assignment for monitor or control group needs to be
done one at a time. For example:

  $mount -t resctrl resctrl /sys/fs/resctrl/
  $mkdir /sys/fs/resctrl/ctrl_grp1
  $echo 123 > /sys/fs/resctrl/ctrl_grp1/tasks
  $echo 456 > /sys/fs/resctrl/ctrl_grp1/tasks
  $echo 789 > /sys/fs/resctrl/ctrl_grp1/tasks

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

Support multiple task assignment in one command with tasks ids separated
by commas. For example:

  $echo 123,456,789 > /sys/fs/resctrl/ctrl_grp1/tasks

Signed-off-by: default avatarBabu Moger <babu.moger@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarPeter Newman <peternewman@google.com>
Reviewed-by: default avatarTan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Reviewed-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: default avatarPeter Newman <peternewman@google.com>
Tested-by: default avatarTan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-2-babu.moger@amd.com
parent aaa5fa35

Documentation/arch/x86/resctrl.rst

+8 −1
Original line number Diff line number Diff line
@@ -306,7 +306,14 @@ 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

	group. Multiple tasks can be added by separating the task ids

	with commas. Tasks will be assigned sequentially. Multiple

	failures are not supported. A single failure encountered while

	attempting to assign a task will cause the operation to abort and

	already added tasks before the failure will remain in the group.

	Failures will be logged to /sys/fs/resctrl/info/last_cmd_status.



	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

arch/x86/kernel/cpu/resctrl/rdtgroup.c

+22 −3
Original line number Diff line number Diff line
@@ -696,11 +696,10 @@ 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)

		return -EINVAL;

	rdtgrp = rdtgroup_kn_lock_live(of->kn);

	if (!rdtgrp) {

		rdtgroup_kn_unlock(of->kn);
@@ -715,7 +714,27 @@ static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of, 
		goto unlock;

	}



	while (buf && buf[0] != '\0' && buf[0] != '\n') {

		pid_str = strim(strsep(&buf, ","));



		if (kstrtoint(pid_str, 0, &pid)) {

			rdt_last_cmd_printf("Task list parsing error pid %s\n", pid_str);

			ret = -EINVAL;

			break;

		}



		if (pid < 0) {

			rdt_last_cmd_printf("Invalid pid %d\n", pid);

			ret = -EINVAL;

			break;

		}



		ret = rdtgroup_move_task(pid, rdtgrp, of);

		if (ret) {

			rdt_last_cmd_printf("Error while processing task %d\n", pid);

			break;

		}

	}



unlock:

	rdtgroup_kn_unlock(of->kn);