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@xxxxxxx> 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@xxxxxxxxxx> >>>> Signed-off-by: Babu Moger <babu.moger@xxxxxxx> >>>> --- >>>> 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@xxxxxxxxx/ >>>> >>>> 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@xxxxxxxxxxxxxx/ >>>> --- >>>> 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@xxxxxxxxx/ How did I miss that? My bad. Will take care of it next revision for sure. -- Thanks Babu Moger
