From d0891647fbc6e931f27517364cbc4ee1811d76db Mon Sep 17 00:00:00 2001 From: Tony Luck Date: Wed, 17 Dec 2025 09:21:15 -0800 Subject: [PATCH] fs/resctrl: Move RMID initialization to first mount L3 monitor features are enumerated during resctrl initialization and rmid_ptrs[] that tracks all RMIDs and depends on the number of supported RMIDs is allocated during this time. Telemetry monitor features are enumerated during first resctrl mount and may support a different number of RMIDs compared to L3 monitor features. Delay allocation and initialization of rmid_ptrs[] until first mount. Since the number of RMIDs cannot change on later mounts, keep the same set of rmid_ptrs[] until resctrl_exit(). This is required because the limbo handler keeps running after resctrl is unmounted and needs to access rmid_ptrs[] as it keeps tracking busy RMIDs after unmount. Rename routines to match what they now do: dom_data_init() -> setup_rmid_lru_list() dom_data_exit() -> free_rmid_lru_list() Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com --- fs/resctrl/internal.h | 4 ++++ fs/resctrl/monitor.c | 54 ++++++++++++++++++++----------------------- fs/resctrl/rdtgroup.c | 5 ++++ 3 files changed, 34 insertions(+), 29 deletions(-) diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h index 399f625be67d3..1a9b29119f88f 100644 --- a/fs/resctrl/internal.h +++ b/fs/resctrl/internal.h @@ -369,6 +369,10 @@ int closids_supported(void); void closid_free(int closid); +int setup_rmid_lru_list(void); + +void free_rmid_lru_list(void); + int alloc_rmid(u32 closid); void free_rmid(u32 closid, u32 rmid); diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c index bbf8c9037887b..0cd5476a483a0 100644 --- a/fs/resctrl/monitor.c +++ b/fs/resctrl/monitor.c @@ -903,20 +903,29 @@ void mbm_setup_overflow_handler(struct rdt_l3_mon_domain *dom, unsigned long del schedule_delayed_work_on(cpu, &dom->mbm_over, delay); } -static int dom_data_init(struct rdt_resource *r) +int setup_rmid_lru_list(void) { - u32 idx_limit = resctrl_arch_system_num_rmid_idx(); struct rmid_entry *entry = NULL; - int err = 0, i; + u32 idx_limit; u32 idx; + int i; - mutex_lock(&rdtgroup_mutex); + if (!resctrl_arch_mon_capable()) + return 0; + /* + * Called on every mount, but the number of RMIDs cannot change + * after the first mount, so keep using the same set of rmid_ptrs[] + * until resctrl_exit(). Note that the limbo handler continues to + * access rmid_ptrs[] after resctrl is unmounted. + */ + if (rmid_ptrs) + return 0; + + idx_limit = resctrl_arch_system_num_rmid_idx(); rmid_ptrs = kcalloc(idx_limit, sizeof(struct rmid_entry), GFP_KERNEL); - if (!rmid_ptrs) { - err = -ENOMEM; - goto out_unlock; - } + if (!rmid_ptrs) + return -ENOMEM; for (i = 0; i < idx_limit; i++) { entry = &rmid_ptrs[i]; @@ -929,30 +938,24 @@ static int dom_data_init(struct rdt_resource *r) /* * RESCTRL_RESERVED_CLOSID and RESCTRL_RESERVED_RMID are special and * are always allocated. These are used for the rdtgroup_default - * control group, which will be setup later in resctrl_init(). + * control group, which was setup earlier in rdtgroup_setup_default(). */ idx = resctrl_arch_rmid_idx_encode(RESCTRL_RESERVED_CLOSID, RESCTRL_RESERVED_RMID); entry = __rmid_entry(idx); list_del(&entry->list); -out_unlock: - mutex_unlock(&rdtgroup_mutex); - - return err; + return 0; } -static void dom_data_exit(struct rdt_resource *r) +void free_rmid_lru_list(void) { - mutex_lock(&rdtgroup_mutex); - - if (!r->mon_capable) - goto out_unlock; + if (!resctrl_arch_mon_capable()) + return; + mutex_lock(&rdtgroup_mutex); kfree(rmid_ptrs); rmid_ptrs = NULL; - -out_unlock: mutex_unlock(&rdtgroup_mutex); } @@ -1830,7 +1833,8 @@ static void closid_num_dirty_rmid_free(void) * resctrl_l3_mon_resource_init() - Initialise global monitoring structures. * * Allocate and initialise global monitor resources that do not belong to a - * specific domain. i.e. the rmid_ptrs[] used for the limbo and free lists. + * specific domain. i.e. the closid_num_dirty_rmid[] used to find the CLOSID + * with the cleanest set of RMIDs. * Called once during boot after the struct rdt_resource's have been configured * but before the filesystem is mounted. * Resctrl's cpuhp callbacks may be called before this point to bring a domain @@ -1850,12 +1854,6 @@ int resctrl_l3_mon_resource_init(void) if (ret) return ret; - ret = dom_data_init(r); - if (ret) { - closid_num_dirty_rmid_free(); - return ret; - } - if (resctrl_arch_is_evt_configurable(QOS_L3_MBM_TOTAL_EVENT_ID)) { mon_event_all[QOS_L3_MBM_TOTAL_EVENT_ID].configurable = true; resctrl_file_fflags_init("mbm_total_bytes_config", @@ -1902,6 +1900,4 @@ void resctrl_l3_mon_resource_exit(void) return; closid_num_dirty_rmid_free(); - - dom_data_exit(r); } diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c index 666cac7661cef..ba8d503551cd1 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -2800,6 +2800,10 @@ static int rdt_get_tree(struct fs_context *fc) goto out; } + ret = setup_rmid_lru_list(); + if (ret) + goto out; + ret = rdtgroup_setup_root(ctx); if (ret) goto out; @@ -4655,4 +4659,5 @@ void resctrl_exit(void) */ resctrl_l3_mon_resource_exit(); + free_rmid_lru_list(); } -- 2.47.3