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. -- Thanks Babu Moger
