[v5] x86/resctrl: Miscellaneous resctrl features

[PATCH v5 1/8] x86/resctrl: Add multiple tasks to the resctrl group at once

Posted by Babu Moger 2 years, 8 months ago

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: Babu Moger <babu.moger@amd.com>
---
 Documentation/arch/x86/resctrl.rst     |    8 +++++++-
 arch/x86/kernel/cpu/resctrl/rdtgroup.c |   30 ++++++++++++++++++++----------
 2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index 387ccbcb558f..290f01aa3002 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -292,7 +292,13 @@ 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
+	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.
+	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
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 6ad33f355861..504137a5d31f 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -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);
@@ -708,16 +707,27 @@ static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of,
 	}
 	rdt_last_cmd_clear();
 
-	if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED ||
-	    rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
-		ret = -EINVAL;
-		rdt_last_cmd_puts("Pseudo-locking in progress\n");
-		goto unlock;
-	}
+	while (buf && buf[0] != '\0') {
+		pid_str = strim(strsep(&buf, ","));
 
-	ret = rdtgroup_move_task(pid, rdtgrp, of);
+		if (kstrtoint(pid_str, 0, &pid)) {
+			rdt_last_cmd_puts("Task list parsing error\n");
+			ret = -EINVAL;
+			break;
+		}
 
-unlock:
+		if (pid < 0) {
+			rdt_last_cmd_printf("Invalid pid %d value\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;
+		}
+	}
 	rdtgroup_kn_unlock(of->kn);
 
 	return ret ?: nbytes;

Re: [PATCH v5 1/8] x86/resctrl: Add multiple tasks to the resctrl group at once

Posted by Reinette Chatre 2 years, 7 months ago

Hi Babu,

On 6/1/2023 12:00 PM, Babu Moger wrote:
> 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: Babu Moger <babu.moger@amd.com>
> ---
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 6ad33f355861..504137a5d31f 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -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);
> @@ -708,16 +707,27 @@ static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of,
>  	}
>  	rdt_last_cmd_clear();
>  
> -	if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED ||
> -	    rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
> -		ret = -EINVAL;
> -		rdt_last_cmd_puts("Pseudo-locking in progress\n");
> -		goto unlock;
> -	}

Please do not drop this snippet. I think there may have been misunderstanding
during previous comments - this snippet is required, it just does not need
to be run for every pid the user provides since it depends on the resource
group, not the pid.

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

I think it may help to add a check for '\n' here also. It looks to me
that a user (shell) that provides "pid,", which is "pid,\n" would encounter
error and this may not actually be an error.

> +		pid_str = strim(strsep(&buf, ","));
>  
> -	ret = rdtgroup_move_task(pid, rdtgrp, of);
> +		if (kstrtoint(pid_str, 0, &pid)) {
> +			rdt_last_cmd_puts("Task list parsing error\n");
> +			ret = -EINVAL;
> +			break;
> +		}
>  
> -unlock:
> +		if (pid < 0) {
> +			rdt_last_cmd_printf("Invalid pid %d value\n", pid);
> +			ret = -EINVAL;
> +			break;
> +		}

I'm trying to image a possible error and it does not look right. For example,
the above could be "Invalid pid 123 value". How about just "Invalid pid %d".

> +
> +		ret = rdtgroup_move_task(pid, rdtgrp, of);
> +		if (ret) {
> +			rdt_last_cmd_printf("Error while processing task %d\n", pid);
> +			break;
> +		}
> +	}
>  	rdtgroup_kn_unlock(of->kn);
>  
>  	return ret ?: nbytes;
> 
> 

Reinette

Re: [PATCH v5 1/8] x86/resctrl: Add multiple tasks to the resctrl group at once

Posted by Moger, Babu 2 years, 7 months ago

Hi Reinette,

On 7/7/23 16:38, Reinette Chatre wrote:
> Hi Babu,
> 
> On 6/1/2023 12:00 PM, Babu Moger wrote:
>> 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: Babu Moger <babu.moger@amd.com>
>> ---
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 6ad33f355861..504137a5d31f 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -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);
>> @@ -708,16 +707,27 @@ static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of,
>>  	}
>>  	rdt_last_cmd_clear();
>>  
>> -	if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED ||
>> -	    rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
>> -		ret = -EINVAL;
>> -		rdt_last_cmd_puts("Pseudo-locking in progress\n");
>> -		goto unlock;
>> -	}
> 
> Please do not drop this snippet. I think there may have been misunderstanding
> during previous comments - this snippet is required, it just does not need
> to be run for every pid the user provides since it depends on the resource
> group, not the pid.

Ok. Got it.

> 
>> +	while (buf && buf[0] != '\0') {
> 
> I think it may help to add a check for '\n' here also. It looks to me
> that a user (shell) that provides "pid,", which is "pid,\n" would encounter
> error and this may not actually be an error.

Ok Sounds good. I have verified it. New check will look like this below.

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

> 
>> +		pid_str = strim(strsep(&buf, ","));
>>  
>> -	ret = rdtgroup_move_task(pid, rdtgrp, of);
>> +		if (kstrtoint(pid_str, 0, &pid)) {
>> +			rdt_last_cmd_puts("Task list parsing error\n");
>> +			ret = -EINVAL;
>> +			break;
>> +		}
>>  
>> -unlock:
>> +		if (pid < 0) {
>> +			rdt_last_cmd_printf("Invalid pid %d value\n", pid);
>> +			ret = -EINVAL;
>> +			break;
>> +		}
> 
> I'm trying to image a possible error and it does not look right. For example,
> the above could be "Invalid pid 123 value". How about just "Invalid pid %d".

Sure.

Thanks
Babu

[PATCH v5 1/8] x86/resctrl: Add multiple tasks to the resctrl group at once
[PATCH v5 2/8] x86/resctrl: Simplify rftype flag definitions
[PATCH v5 3/8] x86/resctrl: Rename rftype flags for consistency
[PATCH v5 4/8] x86/resctrl: Add comments on RFTYPE flags hierarchy
[PATCH v5 5/8] x86/resctrl: Introduce "-o debug" mount option
[PATCH v5 6/8] x86/resctrl: Display CLOSID and RMID for the resctrl groups
[PATCH v5 7/8] x86/resctrl: Move default control group creation during mount
[PATCH v5 8/8] x86/resctrl: Introduce RFTYPE_DEBUG flag