fs/resctrl: Auto assign counters on mkdir and clean up on group removal

Resctrl provides a user-configurable option mbm_assign_on_mkdir that
determines if a counter will automatically be assigned to an RMID, event pair
when its associated monitor group is created via mkdir.

Enable mbm_assign_on_mkdir by default to automatically assign counters to
the two default events (MBM total and MBM local) of a new monitoring group
created via mkdir. This maintains backward compatibility with original
resctrl support for these two events.

Unassign and free counters belonging to a monitoring group when the group
is deleted.

Monitor group creation does not fail if a counter cannot be assigned to one or
both events. There may be limited counters and users have the flexibility to
modify counter assignments at a later time. Log the error message "Failed to
allocate counter for <event> in domain <id>" in
/sys/fs/resctrl/info/last_cmd_status when a new monitoring group is created
but counter assignment failed.

Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com

diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index deca9535fbbb8ef07dfdc7e6968c85fece1b6b5a..9cb334136d210ac77f6e0aa0351663b2c641f67d 100644 (file)
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -1231,7 +1231,8 @@ void rdtgroup_unassign_cntrs(struct rdtgroup *rdtgrp)
 {
        struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
 
-       if (!r->mon_capable || !resctrl_arch_mbm_cntr_assign_enabled(r))
+       if (!r->mon_capable || !resctrl_arch_mbm_cntr_assign_enabled(r) ||
+           !r->mon.mbm_assign_on_mkdir)
                return;
 
        if (resctrl_is_mon_event_enabled(QOS_L3_MBM_TOTAL_EVENT_ID))
@@ -1503,6 +1504,7 @@ int resctrl_mon_resource_init(void)
                                                                   (READS_TO_LOCAL_MEM |
                                                                    READS_TO_LOCAL_S_MEM |
                                                                    NON_TEMP_WRITE_TO_LOCAL_MEM);
+               r->mon.mbm_assign_on_mkdir = true;
                resctrl_file_fflags_init("num_mbm_cntrs",
                                         RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
                resctrl_file_fflags_init("available_mbm_cntrs",

diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index c7ea42c2a3c24ec44e03dde5b225d9848b36e355..48f98146c09962d716664d07dc642a014ef39458 100644 (file)
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -2713,6 +2713,8 @@ static int rdt_get_tree(struct fs_context *fc)
                if (ret < 0)
                        goto out_info;
 
+               rdtgroup_assign_cntrs(&rdtgroup_default);
+
                ret = mkdir_mondata_all(rdtgroup_default.kn,
                                        &rdtgroup_default, &kn_mondata);
                if (ret < 0)
@@ -2751,8 +2753,10 @@ out_mondata:
        if (resctrl_arch_mon_capable())
                kernfs_remove(kn_mondata);
 out_mongrp:
-       if (resctrl_arch_mon_capable())
+       if (resctrl_arch_mon_capable()) {
+               rdtgroup_unassign_cntrs(&rdtgroup_default);
                kernfs_remove(kn_mongrp);
+       }
 out_info:
        kernfs_remove(kn_info);
 out_closid_exit:
@@ -2897,6 +2901,7 @@ static void free_all_child_rdtgrp(struct rdtgroup *rdtgrp)
 
        head = &rdtgrp->mon.crdtgrp_list;
        list_for_each_entry_safe(sentry, stmp, head, mon.crdtgrp_list) {
+               rdtgroup_unassign_cntrs(sentry);
                free_rmid(sentry->closid, sentry->mon.rmid);
                list_del(&sentry->mon.crdtgrp_list);
 
@@ -2937,6 +2942,8 @@ static void rmdir_all_sub(void)
                cpumask_or(&rdtgroup_default.cpu_mask,
                           &rdtgroup_default.cpu_mask, &rdtgrp->cpu_mask);
 
+               rdtgroup_unassign_cntrs(rdtgrp);
+
                free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
 
                kernfs_remove(rdtgrp->kn);
@@ -3021,6 +3028,7 @@ static void resctrl_fs_teardown(void)
                return;
 
        rmdir_all_sub();
+       rdtgroup_unassign_cntrs(&rdtgroup_default);
        mon_put_kn_priv();
        rdt_pseudo_lock_release();
        rdtgroup_default.mode = RDT_MODE_SHAREABLE;
@@ -3501,9 +3509,12 @@ static int mkdir_rdt_prepare_rmid_alloc(struct rdtgroup *rdtgrp)
        }
        rdtgrp->mon.rmid = ret;
 
+       rdtgroup_assign_cntrs(rdtgrp);
+
        ret = mkdir_mondata_all(rdtgrp->kn, rdtgrp, &rdtgrp->mon.mon_data_kn);
        if (ret) {
                rdt_last_cmd_puts("kernfs subdir error\n");
+               rdtgroup_unassign_cntrs(rdtgrp);
                free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
                return ret;
        }
@@ -3513,8 +3524,10 @@ static int mkdir_rdt_prepare_rmid_alloc(struct rdtgroup *rdtgrp)
 
 static void mkdir_rdt_prepare_rmid_free(struct rdtgroup *rgrp)
 {
-       if (resctrl_arch_mon_capable())
+       if (resctrl_arch_mon_capable()) {
+               rdtgroup_unassign_cntrs(rgrp);
                free_rmid(rgrp->closid, rgrp->mon.rmid);
+       }
 }
 
 /*
@@ -3790,6 +3803,9 @@ static int rdtgroup_rmdir_mon(struct rdtgroup *rdtgrp, cpumask_var_t tmpmask)
        update_closid_rmid(tmpmask, NULL);
 
        rdtgrp->flags = RDT_DELETED;
+
+       rdtgroup_unassign_cntrs(rdtgrp);
+
        free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
 
        /*
@@ -3837,6 +3853,8 @@ static int rdtgroup_rmdir_ctrl(struct rdtgroup *rdtgrp, cpumask_var_t tmpmask)
        cpumask_or(tmpmask, tmpmask, &rdtgrp->cpu_mask);
        update_closid_rmid(tmpmask, NULL);
 
+       rdtgroup_unassign_cntrs(rdtgrp);
+
        free_rmid(rdtgrp->closid, rdtgrp->mon.rmid);
        closid_free(rdtgrp->closid);