From: Babu Moger Date: Fri, 5 Sep 2025 21:34:25 +0000 (-0500) Subject: fs/resctrl: Introduce mbm_assign_on_mkdir to enable assignments on mkdir X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ac1df9bb0ba3ae94137fb494cd9efc598f65d826;p=users%2Fhch%2Fmisc.git fs/resctrl: Introduce mbm_assign_on_mkdir to enable assignments on mkdir 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. Accessible when "mbm_event" counter assignment mode is enabled. Suggested-by: Peter Newman Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com --- diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst index 2e840ef26f68..1de815b3a07b 100644 --- a/Documentation/filesystems/resctrl.rst +++ b/Documentation/filesystems/resctrl.rst @@ -355,6 +355,26 @@ 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": + Exists when "mbm_event" counter assignment mode is supported. Accessible + only when "mbm_event" counter assignment mode is enabled. + + Determines if a counter will automatically be assigned to an RMID, MBM event + pair when its associated monitor group is created via mkdir. Enabled by default + on boot, also when switched from "default" mode to "mbm_event" counter assignment + mode. Users can disable this capability 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/internal.h b/fs/resctrl/internal.h index 90d3e4ab335b..66c677c1b858 100644 --- a/fs/resctrl/internal.h +++ b/fs/resctrl/internal.h @@ -410,6 +410,12 @@ int event_filter_show(struct kernfs_open_file *of, struct seq_file *seq, void *v ssize_t event_filter_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off); +int resctrl_mbm_assign_on_mkdir_show(struct kernfs_open_file *of, + struct seq_file *s, void *v); + +ssize_t resctrl_mbm_assign_on_mkdir_write(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off); + #ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp); diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c index ccb9726bba54..deca9535fbbb 100644 --- a/fs/resctrl/monitor.c +++ b/fs/resctrl/monitor.c @@ -1027,6 +1027,57 @@ out_unlock: return ret; } +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); + int ret = 0; + + mutex_lock(&rdtgroup_mutex); + rdt_last_cmd_clear(); + + if (!resctrl_arch_mbm_cntr_assign_enabled(r)) { + rdt_last_cmd_puts("mbm_event counter assignment mode is not enabled\n"); + ret = -EINVAL; + goto out_unlock; + } + + seq_printf(s, "%u\n", r->mon.mbm_assign_on_mkdir); + +out_unlock: + mutex_unlock(&rdtgroup_mutex); + + return ret; +} + +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(); + + if (!resctrl_arch_mbm_cntr_assign_enabled(r)) { + rdt_last_cmd_puts("mbm_event counter assignment mode is not enabled\n"); + ret = -EINVAL; + goto out_unlock; + } + + r->mon.mbm_assign_on_mkdir = value; + +out_unlock: + mutex_unlock(&rdtgroup_mutex); + + return ret ?: nbytes; +} + /* * rdtgroup_assign_cntr() - Assign/unassign the counter ID for the event, RMID * pair in the domain. @@ -1457,6 +1508,8 @@ 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 e90bc808fe53..c7ea42c2a3c2 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -1808,6 +1808,13 @@ 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 04152654827d..a7d92718b653 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; }; /**