The "mbm_event" counter assignment mode allows users to assign a hardware
counter to an RMID, event pair and monitor the bandwidth as long as it is
assigned.
Introduce a user-configurable option that determines if a counter will
automatically be assigned to an RMID, event pair when its associated
monitor group is created via mkdir.
Suggested-by: Peter Newman <peternewman@google.com>
Signed-off-by: Babu Moger <babu.moger@amd.com>
---
v15: Fixed the static checker warning in resctrl_mbm_assign_on_mkdir_write() reported in
https://lore.kernel.org/lkml/dd4a1021-b996-438e-941c-69dfcea5f22a@intel.com/
v14: Added rdtgroup_mutex in resctrl_mbm_assign_on_mkdir_show().
Updated resctrl.rst for clarity.
Fixed squashing of few previous changes.
Added more code documentation.
v13: Added Suggested-by tag.
Resolved conflicts caused by the recent FS/ARCH code restructure.
The rdtgroup.c/monitor.c file has now been split between the FS and ARCH directories.
v12: New patch. Added after the discussion on the list.
https://lore.kernel.org/lkml/CALPaoCh8siZKjL_3yvOYGL4cF_n_38KpUFgHVGbQ86nD+Q2_SA@mail.gmail.com/
---
Documentation/filesystems/resctrl.rst | 16 ++++++++++
fs/resctrl/monitor.c | 2 ++
fs/resctrl/rdtgroup.c | 43 +++++++++++++++++++++++++++
include/linux/resctrl.h | 3 ++
4 files changed, 64 insertions(+)
diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index 06c8c08d0341..f9e9a8a66cae 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -354,6 +354,22 @@ with the following files:
# cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_total_bytes/event_filter
local_reads,local_non_temporal_writes
+"mbm_assign_on_mkdir":
+ Determines if a counter will automatically be assigned to an RMID, event pair
+ when its associated monitor group is created via mkdir. It is enabled by default
+ on boot and users can disable by writing to the interface.
+
+ "0":
+ Auto assignment is disabled.
+ "1":
+ Auto assignment is enabled.
+
+ Example::
+
+ # echo 0 > /sys/fs/resctrl/info/L3_MON/mbm_assign_on_mkdir
+ # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_on_mkdir
+ 0
+
"max_threshold_occupancy":
Read/write file provides the largest value (in
bytes) at which a previously used LLC_occupancy
diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index 0722e72f6cb1..ccca2330eebd 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -984,6 +984,8 @@ int resctrl_mon_resource_init(void)
resctrl_file_fflags_init("available_mbm_cntrs",
RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
resctrl_file_fflags_init("event_filter", RFTYPE_ASSIGN_CONFIG);
+ resctrl_file_fflags_init("mbm_assign_on_mkdir", RFTYPE_MON_INFO |
+ RFTYPE_RES_CACHE);
}
return 0;
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 4889e7556cc7..b7289ce2b3a6 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1987,6 +1987,42 @@ static ssize_t event_filter_write(struct kernfs_open_file *of, char *buf,
return ret ?: nbytes;
}
+static int resctrl_mbm_assign_on_mkdir_show(struct kernfs_open_file *of,
+ struct seq_file *s, void *v)
+{
+ struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
+
+ mutex_lock(&rdtgroup_mutex);
+ rdt_last_cmd_clear();
+
+ seq_printf(s, "%u\n", r->mon.mbm_assign_on_mkdir);
+
+ mutex_unlock(&rdtgroup_mutex);
+
+ return 0;
+}
+
+static ssize_t resctrl_mbm_assign_on_mkdir_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
+ bool value;
+ int ret;
+
+ ret = kstrtobool(buf, &value);
+ if (ret)
+ return ret;
+
+ mutex_lock(&rdtgroup_mutex);
+ rdt_last_cmd_clear();
+
+ r->mon.mbm_assign_on_mkdir = value;
+
+ mutex_unlock(&rdtgroup_mutex);
+
+ return 0;
+}
+
/* rdtgroup information files for one cache resource. */
static struct rftype res_common_files[] = {
{
@@ -1996,6 +2032,13 @@ static struct rftype res_common_files[] = {
.seq_show = rdt_last_cmd_status_show,
.fflags = RFTYPE_TOP_INFO,
},
+ {
+ .name = "mbm_assign_on_mkdir",
+ .mode = 0644,
+ .kf_ops = &rdtgroup_kf_single_ops,
+ .seq_show = resctrl_mbm_assign_on_mkdir_show,
+ .write = resctrl_mbm_assign_on_mkdir_write,
+ },
{
.name = "num_closids",
.mode = 0444,
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 96679ad49d66..74a036067135 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -277,12 +277,15 @@ enum resctrl_schema_fmt {
* monitoring events can be configured.
* @num_mbm_cntrs: Number of assignable counters.
* @mbm_cntr_assignable:Is system capable of supporting counter assignment?
+ * @mbm_assign_on_mkdir:True if counters should automatically be assigned to MBM
+ * events of monitor groups created via mkdir.
*/
struct resctrl_mon {
int num_rmid;
unsigned int mbm_cfg_mask;
int num_mbm_cntrs;
bool mbm_cntr_assignable;
+ bool mbm_assign_on_mkdir;
};
/**
--
2.34.1Hi Babu,
On Wed, Jul 9, 2025 at 12:22 AM Babu Moger <babu.moger@amd.com> wrote:
>
> The "mbm_event" counter assignment mode allows users to assign a hardware
> counter to an RMID, event pair and monitor the bandwidth as long as it is
> assigned.
>
> Introduce a user-configurable option that determines if a counter will
> automatically be assigned to an RMID, event pair when its associated
> monitor group is created via mkdir.
>
> Suggested-by: Peter Newman <peternewman@google.com>
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---
> v15: Fixed the static checker warning in resctrl_mbm_assign_on_mkdir_write() reported in
> https://lore.kernel.org/lkml/dd4a1021-b996-438e-941c-69dfcea5f22a@intel.com/
>
> v14: Added rdtgroup_mutex in resctrl_mbm_assign_on_mkdir_show().
> Updated resctrl.rst for clarity.
> Fixed squashing of few previous changes.
> Added more code documentation.
>
> v13: Added Suggested-by tag.
> Resolved conflicts caused by the recent FS/ARCH code restructure.
> The rdtgroup.c/monitor.c file has now been split between the FS and ARCH directories.
>
> v12: New patch. Added after the discussion on the list.
> https://lore.kernel.org/lkml/CALPaoCh8siZKjL_3yvOYGL4cF_n_38KpUFgHVGbQ86nD+Q2_SA@mail.gmail.com/
> ---
> Documentation/filesystems/resctrl.rst | 16 ++++++++++
> fs/resctrl/monitor.c | 2 ++
> fs/resctrl/rdtgroup.c | 43 +++++++++++++++++++++++++++
> include/linux/resctrl.h | 3 ++
> 4 files changed, 64 insertions(+)
>
> diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
> index 06c8c08d0341..f9e9a8a66cae 100644
> --- a/Documentation/filesystems/resctrl.rst
> +++ b/Documentation/filesystems/resctrl.rst
> @@ -354,6 +354,22 @@ with the following files:
> # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_total_bytes/event_filter
> local_reads,local_non_temporal_writes
>
> +"mbm_assign_on_mkdir":
> + Determines if a counter will automatically be assigned to an RMID, event pair
> + when its associated monitor group is created via mkdir. It is enabled by default
> + on boot and users can disable by writing to the interface.
> +
> + "0":
> + Auto assignment is disabled.
> + "1":
> + Auto assignment is enabled.
> +
> + Example::
> +
> + # echo 0 > /sys/fs/resctrl/info/L3_MON/mbm_assign_on_mkdir
> + # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_on_mkdir
> + 0
> +
> "max_threshold_occupancy":
> Read/write file provides the largest value (in
> bytes) at which a previously used LLC_occupancy
> diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
> index 0722e72f6cb1..ccca2330eebd 100644
> --- a/fs/resctrl/monitor.c
> +++ b/fs/resctrl/monitor.c
> @@ -984,6 +984,8 @@ int resctrl_mon_resource_init(void)
> resctrl_file_fflags_init("available_mbm_cntrs",
> RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
> resctrl_file_fflags_init("event_filter", RFTYPE_ASSIGN_CONFIG);
> + resctrl_file_fflags_init("mbm_assign_on_mkdir", RFTYPE_MON_INFO |
> + RFTYPE_RES_CACHE);
> }
>
> return 0;
> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
> index 4889e7556cc7..b7289ce2b3a6 100644
> --- a/fs/resctrl/rdtgroup.c
> +++ b/fs/resctrl/rdtgroup.c
> @@ -1987,6 +1987,42 @@ static ssize_t event_filter_write(struct kernfs_open_file *of, char *buf,
> return ret ?: nbytes;
> }
>
> +static int resctrl_mbm_assign_on_mkdir_show(struct kernfs_open_file *of,
> + struct seq_file *s, void *v)
> +{
> + struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
> +
> + mutex_lock(&rdtgroup_mutex);
> + rdt_last_cmd_clear();
> +
> + seq_printf(s, "%u\n", r->mon.mbm_assign_on_mkdir);
> +
> + mutex_unlock(&rdtgroup_mutex);
> +
> + return 0;
> +}
> +
> +static ssize_t resctrl_mbm_assign_on_mkdir_write(struct kernfs_open_file *of,
> + char *buf, size_t nbytes, loff_t off)
> +{
> + struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
> + bool value;
> + int ret;
> +
> + ret = kstrtobool(buf, &value);
> + if (ret)
> + return ret;
> +
> + mutex_lock(&rdtgroup_mutex);
> + rdt_last_cmd_clear();
> +
> + r->mon.mbm_assign_on_mkdir = value;
> +
> + mutex_unlock(&rdtgroup_mutex);
> +
> + return 0;
I noticed that "echo 0 > mbm_assign_on_mkdir" never completes. This
should return nbytes.
Thanks,
-Peter
Hi Peter,
On 7/15/25 08:53, Peter Newman wrote:
> Hi Babu,
>
> On Wed, Jul 9, 2025 at 12:22 AM Babu Moger <babu.moger@amd.com> wrote:
>>
>> The "mbm_event" counter assignment mode allows users to assign a hardware
>> counter to an RMID, event pair and monitor the bandwidth as long as it is
>> assigned.
>>
>> Introduce a user-configurable option that determines if a counter will
>> automatically be assigned to an RMID, event pair when its associated
>> monitor group is created via mkdir.
>>
>> Suggested-by: Peter Newman <peternewman@google.com>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>> v15: Fixed the static checker warning in resctrl_mbm_assign_on_mkdir_write() reported in
>> https://lore.kernel.org/lkml/dd4a1021-b996-438e-941c-69dfcea5f22a@intel.com/
>>
>> v14: Added rdtgroup_mutex in resctrl_mbm_assign_on_mkdir_show().
>> Updated resctrl.rst for clarity.
>> Fixed squashing of few previous changes.
>> Added more code documentation.
>>
>> v13: Added Suggested-by tag.
>> Resolved conflicts caused by the recent FS/ARCH code restructure.
>> The rdtgroup.c/monitor.c file has now been split between the FS and ARCH directories.
>>
>> v12: New patch. Added after the discussion on the list.
>> https://lore.kernel.org/lkml/CALPaoCh8siZKjL_3yvOYGL4cF_n_38KpUFgHVGbQ86nD+Q2_SA@mail.gmail.com/
>> ---
>> Documentation/filesystems/resctrl.rst | 16 ++++++++++
>> fs/resctrl/monitor.c | 2 ++
>> fs/resctrl/rdtgroup.c | 43 +++++++++++++++++++++++++++
>> include/linux/resctrl.h | 3 ++
>> 4 files changed, 64 insertions(+)
>>
>> diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
>> index 06c8c08d0341..f9e9a8a66cae 100644
>> --- a/Documentation/filesystems/resctrl.rst
>> +++ b/Documentation/filesystems/resctrl.rst
>> @@ -354,6 +354,22 @@ with the following files:
>> # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_total_bytes/event_filter
>> local_reads,local_non_temporal_writes
>>
>> +"mbm_assign_on_mkdir":
>> + Determines if a counter will automatically be assigned to an RMID, event pair
>> + when its associated monitor group is created via mkdir. It is enabled by default
>> + on boot and users can disable by writing to the interface.
>> +
>> + "0":
>> + Auto assignment is disabled.
>> + "1":
>> + Auto assignment is enabled.
>> +
>> + Example::
>> +
>> + # echo 0 > /sys/fs/resctrl/info/L3_MON/mbm_assign_on_mkdir
>> + # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_on_mkdir
>> + 0
>> +
>> "max_threshold_occupancy":
>> Read/write file provides the largest value (in
>> bytes) at which a previously used LLC_occupancy
>> diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
>> index 0722e72f6cb1..ccca2330eebd 100644
>> --- a/fs/resctrl/monitor.c
>> +++ b/fs/resctrl/monitor.c
>> @@ -984,6 +984,8 @@ int resctrl_mon_resource_init(void)
>> resctrl_file_fflags_init("available_mbm_cntrs",
>> RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
>> resctrl_file_fflags_init("event_filter", RFTYPE_ASSIGN_CONFIG);
>> + resctrl_file_fflags_init("mbm_assign_on_mkdir", RFTYPE_MON_INFO |
>> + RFTYPE_RES_CACHE);
>> }
>>
>> return 0;
>> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
>> index 4889e7556cc7..b7289ce2b3a6 100644
>> --- a/fs/resctrl/rdtgroup.c
>> +++ b/fs/resctrl/rdtgroup.c
>> @@ -1987,6 +1987,42 @@ static ssize_t event_filter_write(struct kernfs_open_file *of, char *buf,
>> return ret ?: nbytes;
>> }
>>
>> +static int resctrl_mbm_assign_on_mkdir_show(struct kernfs_open_file *of,
>> + struct seq_file *s, void *v)
>> +{
>> + struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
>> +
>> + mutex_lock(&rdtgroup_mutex);
>> + rdt_last_cmd_clear();
>> +
>> + seq_printf(s, "%u\n", r->mon.mbm_assign_on_mkdir);
>> +
>> + mutex_unlock(&rdtgroup_mutex);
>> +
>> + return 0;
>> +}
>> +
>> +static ssize_t resctrl_mbm_assign_on_mkdir_write(struct kernfs_open_file *of,
>> + char *buf, size_t nbytes, loff_t off)
>> +{
>> + struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
>> + bool value;
>> + int ret;
>> +
>> + ret = kstrtobool(buf, &value);
>> + if (ret)
>> + return ret;
>> +
>> + mutex_lock(&rdtgroup_mutex);
>> + rdt_last_cmd_clear();
>> +
>> + r->mon.mbm_assign_on_mkdir = value;
>> +
>> + mutex_unlock(&rdtgroup_mutex);
>> +
>> + return 0;
>
> I noticed that "echo 0 > mbm_assign_on_mkdir" never completes. This
> should return nbytes.
>
Agree. Thanks for pointing it out.
--
Thanks
Babu Moger
On 7/15/25 7:18 AM, Moger, Babu wrote:
> Hi Peter,
>
> On 7/15/25 08:53, Peter Newman wrote:
>> Hi Babu,
>>
>> On Wed, Jul 9, 2025 at 12:22 AM Babu Moger <babu.moger@amd.com> wrote:
>>>
>>> The "mbm_event" counter assignment mode allows users to assign a hardware
>>> counter to an RMID, event pair and monitor the bandwidth as long as it is
>>> assigned.
>>>
>>> Introduce a user-configurable option that determines if a counter will
>>> automatically be assigned to an RMID, event pair when its associated
>>> monitor group is created via mkdir.
>>>
>>> Suggested-by: Peter Newman <peternewman@google.com>
>>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>>> ---
>>> v15: Fixed the static checker warning in resctrl_mbm_assign_on_mkdir_write() reported in
>>> https://lore.kernel.org/lkml/dd4a1021-b996-438e-941c-69dfcea5f22a@intel.com/
>>>
>>> v14: Added rdtgroup_mutex in resctrl_mbm_assign_on_mkdir_show().
>>> Updated resctrl.rst for clarity.
>>> Fixed squashing of few previous changes.
>>> Added more code documentation.
>>>
>>> v13: Added Suggested-by tag.
>>> Resolved conflicts caused by the recent FS/ARCH code restructure.
>>> The rdtgroup.c/monitor.c file has now been split between the FS and ARCH directories.
>>>
>>> v12: New patch. Added after the discussion on the list.
>>> https://lore.kernel.org/lkml/CALPaoCh8siZKjL_3yvOYGL4cF_n_38KpUFgHVGbQ86nD+Q2_SA@mail.gmail.com/
>>> ---
>>> Documentation/filesystems/resctrl.rst | 16 ++++++++++
>>> fs/resctrl/monitor.c | 2 ++
>>> fs/resctrl/rdtgroup.c | 43 +++++++++++++++++++++++++++
>>> include/linux/resctrl.h | 3 ++
>>> 4 files changed, 64 insertions(+)
>>>
>>> diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
>>> index 06c8c08d0341..f9e9a8a66cae 100644
>>> --- a/Documentation/filesystems/resctrl.rst
>>> +++ b/Documentation/filesystems/resctrl.rst
>>> @@ -354,6 +354,22 @@ with the following files:
>>> # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_total_bytes/event_filter
>>> local_reads,local_non_temporal_writes
>>>
>>> +"mbm_assign_on_mkdir":
>>> + Determines if a counter will automatically be assigned to an RMID, event pair
>>> + when its associated monitor group is created via mkdir. It is enabled by default
>>> + on boot and users can disable by writing to the interface.
>>> +
>>> + "0":
>>> + Auto assignment is disabled.
>>> + "1":
>>> + Auto assignment is enabled.
>>> +
>>> + Example::
>>> +
>>> + # echo 0 > /sys/fs/resctrl/info/L3_MON/mbm_assign_on_mkdir
>>> + # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_on_mkdir
>>> + 0
>>> +
>>> "max_threshold_occupancy":
>>> Read/write file provides the largest value (in
>>> bytes) at which a previously used LLC_occupancy
>>> diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
>>> index 0722e72f6cb1..ccca2330eebd 100644
>>> --- a/fs/resctrl/monitor.c
>>> +++ b/fs/resctrl/monitor.c
>>> @@ -984,6 +984,8 @@ int resctrl_mon_resource_init(void)
>>> resctrl_file_fflags_init("available_mbm_cntrs",
>>> RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
>>> resctrl_file_fflags_init("event_filter", RFTYPE_ASSIGN_CONFIG);
>>> + resctrl_file_fflags_init("mbm_assign_on_mkdir", RFTYPE_MON_INFO |
>>> + RFTYPE_RES_CACHE);
>>> }
>>>
>>> return 0;
>>> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
>>> index 4889e7556cc7..b7289ce2b3a6 100644
>>> --- a/fs/resctrl/rdtgroup.c
>>> +++ b/fs/resctrl/rdtgroup.c
>>> @@ -1987,6 +1987,42 @@ static ssize_t event_filter_write(struct kernfs_open_file *of, char *buf,
>>> return ret ?: nbytes;
>>> }
>>>
>>> +static int resctrl_mbm_assign_on_mkdir_show(struct kernfs_open_file *of,
>>> + struct seq_file *s, void *v)
>>> +{
>>> + struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
>>> +
>>> + mutex_lock(&rdtgroup_mutex);
>>> + rdt_last_cmd_clear();
>>> +
>>> + seq_printf(s, "%u\n", r->mon.mbm_assign_on_mkdir);
>>> +
>>> + mutex_unlock(&rdtgroup_mutex);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static ssize_t resctrl_mbm_assign_on_mkdir_write(struct kernfs_open_file *of,
>>> + char *buf, size_t nbytes, loff_t off)
>>> +{
>>> + struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
>>> + bool value;
>>> + int ret;
>>> +
>>> + ret = kstrtobool(buf, &value);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + mutex_lock(&rdtgroup_mutex);
>>> + rdt_last_cmd_clear();
>>> +
>>> + r->mon.mbm_assign_on_mkdir = value;
>>> +
>>> + mutex_unlock(&rdtgroup_mutex);
>>> +
>>> + return 0;
>>
>> I noticed that "echo 0 > mbm_assign_on_mkdir" never completes. This
>> should return nbytes.
>>
>
> Agree. Thanks for pointing it out.
Not the first time:
https://lore.kernel.org/lkml/7fcdb142-b188-4f8d-ab26-391e0b9cec8e@intel.com/
Reinette
Hi Reinette,
On 7/15/25 09:27, Reinette Chatre wrote:
>
>
> On 7/15/25 7:18 AM, Moger, Babu wrote:
>> Hi Peter,
>>
>> On 7/15/25 08:53, Peter Newman wrote:
>>> Hi Babu,
>>>
>>> On Wed, Jul 9, 2025 at 12:22 AM Babu Moger <babu.moger@amd.com> wrote:
>>>>
>>>> The "mbm_event" counter assignment mode allows users to assign a hardware
>>>> counter to an RMID, event pair and monitor the bandwidth as long as it is
>>>> assigned.
>>>>
>>>> Introduce a user-configurable option that determines if a counter will
>>>> automatically be assigned to an RMID, event pair when its associated
>>>> monitor group is created via mkdir.
>>>>
>>>> Suggested-by: Peter Newman <peternewman@google.com>
>>>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>>>> ---
>>>> v15: Fixed the static checker warning in resctrl_mbm_assign_on_mkdir_write() reported in
>>>> https://lore.kernel.org/lkml/dd4a1021-b996-438e-941c-69dfcea5f22a@intel.com/
>>>>
>>>> v14: Added rdtgroup_mutex in resctrl_mbm_assign_on_mkdir_show().
>>>> Updated resctrl.rst for clarity.
>>>> Fixed squashing of few previous changes.
>>>> Added more code documentation.
>>>>
>>>> v13: Added Suggested-by tag.
>>>> Resolved conflicts caused by the recent FS/ARCH code restructure.
>>>> The rdtgroup.c/monitor.c file has now been split between the FS and ARCH directories.
>>>>
>>>> v12: New patch. Added after the discussion on the list.
>>>> https://lore.kernel.org/lkml/CALPaoCh8siZKjL_3yvOYGL4cF_n_38KpUFgHVGbQ86nD+Q2_SA@mail.gmail.com/
>>>> ---
>>>> Documentation/filesystems/resctrl.rst | 16 ++++++++++
>>>> fs/resctrl/monitor.c | 2 ++
>>>> fs/resctrl/rdtgroup.c | 43 +++++++++++++++++++++++++++
>>>> include/linux/resctrl.h | 3 ++
>>>> 4 files changed, 64 insertions(+)
>>>>
>>>> diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
>>>> index 06c8c08d0341..f9e9a8a66cae 100644
>>>> --- a/Documentation/filesystems/resctrl.rst
>>>> +++ b/Documentation/filesystems/resctrl.rst
>>>> @@ -354,6 +354,22 @@ with the following files:
>>>> # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_total_bytes/event_filter
>>>> local_reads,local_non_temporal_writes
>>>>
>>>> +"mbm_assign_on_mkdir":
>>>> + Determines if a counter will automatically be assigned to an RMID, event pair
>>>> + when its associated monitor group is created via mkdir. It is enabled by default
>>>> + on boot and users can disable by writing to the interface.
>>>> +
>>>> + "0":
>>>> + Auto assignment is disabled.
>>>> + "1":
>>>> + Auto assignment is enabled.
>>>> +
>>>> + Example::
>>>> +
>>>> + # echo 0 > /sys/fs/resctrl/info/L3_MON/mbm_assign_on_mkdir
>>>> + # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_on_mkdir
>>>> + 0
>>>> +
>>>> "max_threshold_occupancy":
>>>> Read/write file provides the largest value (in
>>>> bytes) at which a previously used LLC_occupancy
>>>> diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
>>>> index 0722e72f6cb1..ccca2330eebd 100644
>>>> --- a/fs/resctrl/monitor.c
>>>> +++ b/fs/resctrl/monitor.c
>>>> @@ -984,6 +984,8 @@ int resctrl_mon_resource_init(void)
>>>> resctrl_file_fflags_init("available_mbm_cntrs",
>>>> RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
>>>> resctrl_file_fflags_init("event_filter", RFTYPE_ASSIGN_CONFIG);
>>>> + resctrl_file_fflags_init("mbm_assign_on_mkdir", RFTYPE_MON_INFO |
>>>> + RFTYPE_RES_CACHE);
>>>> }
>>>>
>>>> return 0;
>>>> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
>>>> index 4889e7556cc7..b7289ce2b3a6 100644
>>>> --- a/fs/resctrl/rdtgroup.c
>>>> +++ b/fs/resctrl/rdtgroup.c
>>>> @@ -1987,6 +1987,42 @@ static ssize_t event_filter_write(struct kernfs_open_file *of, char *buf,
>>>> return ret ?: nbytes;
>>>> }
>>>>
>>>> +static int resctrl_mbm_assign_on_mkdir_show(struct kernfs_open_file *of,
>>>> + struct seq_file *s, void *v)
>>>> +{
>>>> + struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
>>>> +
>>>> + mutex_lock(&rdtgroup_mutex);
>>>> + rdt_last_cmd_clear();
>>>> +
>>>> + seq_printf(s, "%u\n", r->mon.mbm_assign_on_mkdir);
>>>> +
>>>> + mutex_unlock(&rdtgroup_mutex);
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static ssize_t resctrl_mbm_assign_on_mkdir_write(struct kernfs_open_file *of,
>>>> + char *buf, size_t nbytes, loff_t off)
>>>> +{
>>>> + struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
>>>> + bool value;
>>>> + int ret;
>>>> +
>>>> + ret = kstrtobool(buf, &value);
>>>> + if (ret)
>>>> + return ret;
>>>> +
>>>> + mutex_lock(&rdtgroup_mutex);
>>>> + rdt_last_cmd_clear();
>>>> +
>>>> + r->mon.mbm_assign_on_mkdir = value;
>>>> +
>>>> + mutex_unlock(&rdtgroup_mutex);
>>>> +
>>>> + return 0;
>>>
>>> I noticed that "echo 0 > mbm_assign_on_mkdir" never completes. This
>>> should return nbytes.
>>>
>>
>> Agree. Thanks for pointing it out.
>
> Not the first time:
> https://lore.kernel.org/lkml/7fcdb142-b188-4f8d-ab26-391e0b9cec8e@intel.com/
How did I miss that? My bad. Will take care of it next revision for sure.
--
Thanks
Babu Moger
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