[PATCH v6 17/22] x86/resctrl: Assign/unassign counters by default when ABMC is enabled

[Babu Moger <babu.moger@amd.com>]

Assign/unassign counters on resctrl group creation/deletion. Two counters
are required per group, one for total event and one for local event.

There are only limited number of counters for assignment. If the counters
are exhausted, report the warnings and continue. It is not required to
fail group creation for assignment failures. Users have the option to
modify the assignments later.

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
v6: Removed the redundant comments on all the calls of
    rdtgroup_assign_cntrs. Updated the commit message.
    Dropped printing error message on every call of rdtgroup_assign_cntrs.

v5: Removed the code to enable/disable ABMC during the mount.
    That will be another patch.
    Added arch callers to get the arch specific data.
    Renamed fuctions to match the other abmc function.
    Added code comments for assignment failures.

v4: Few name changes based on the upstream discussion.
    Commit message update.

v3: This is a new patch. Patch addresses the upstream comment to enable
    ABMC feature by default if the feature is available.
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 55 ++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 0c2215dbd497..d93c1d784b91 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2908,6 +2908,46 @@ static void schemata_list_destroy(void)
 	}
 }
 
+/*
+ * Called when new group is created. Assign the counters if ABMC is
+ * already enabled. Two counters are required per group, one for total
+ * event and one for local event. With limited number of counters,
+ * the assignments can fail in some cases. But, it is not required to
+ * fail the group creation. Users have the option to modify the
+ * assignments after the group creation.
+ */
+static int rdtgroup_assign_cntrs(struct rdtgroup *rdtgrp)
+{
+	int ret = 0;
+
+	if (!resctrl_arch_get_abmc_enabled())
+		return 0;
+
+	if (is_mbm_total_enabled())
+		ret = rdtgroup_assign_cntr(rdtgrp, QOS_L3_MBM_TOTAL_EVENT_ID);
+
+	if (!ret && is_mbm_local_enabled())
+		ret = rdtgroup_assign_cntr(rdtgrp, QOS_L3_MBM_LOCAL_EVENT_ID);
+
+	return ret;
+}
+
+static int rdtgroup_unassign_cntrs(struct rdtgroup *rdtgrp)
+{
+	int ret = 0;
+
+	if (!resctrl_arch_get_abmc_enabled())
+		return 0;
+
+	if (is_mbm_total_enabled())
+		ret = rdtgroup_unassign_cntr(rdtgrp, QOS_L3_MBM_TOTAL_EVENT_ID);
+
+	if (!ret && is_mbm_local_enabled())
+		ret = rdtgroup_unassign_cntr(rdtgrp, QOS_L3_MBM_LOCAL_EVENT_ID);
+
+	return ret;
+}
+
 static int rdt_get_tree(struct fs_context *fc)
 {
 	struct rdt_fs_context *ctx = rdt_fc2context(fc);
@@ -2969,6 +3009,8 @@ static int rdt_get_tree(struct fs_context *fc)
 		if (ret < 0)
 			goto out_mongrp;
 		rdtgroup_default.mon.mon_data_kn = kn_mondata;
+
+		rdtgroup_assign_cntrs(&rdtgroup_default);
 	}
 
 	ret = rdt_pseudo_lock_init();
@@ -2999,6 +3041,7 @@ static int rdt_get_tree(struct fs_context *fc)
 out_psl:
 	rdt_pseudo_lock_release();
 out_mondata:
+	rdtgroup_unassign_cntrs(&rdtgroup_default);
 	if (resctrl_arch_mon_capable())
 		kernfs_remove(kn_mondata);
 out_mongrp:
@@ -3258,6 +3301,8 @@ static void rdt_kill_sb(struct super_block *sb)
 		resctrl_arch_disable_alloc();
 	if (resctrl_arch_mon_capable())
 		resctrl_arch_disable_mon();
+
+	rdtgroup_unassign_cntrs(&rdtgroup_default);
 	resctrl_mounted = false;
 	kernfs_kill_sb(sb);
 	mutex_unlock(&rdtgroup_mutex);
@@ -3849,6 +3894,8 @@ static int rdtgroup_mkdir_mon(struct kernfs_node *parent_kn,
 		goto out_unlock;
 	}
 
+	rdtgroup_assign_cntrs(rdtgrp);
+
 	kernfs_activate(rdtgrp->kn);
 
 	/*
@@ -3893,6 +3940,8 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
 	if (ret)
 		goto out_closid_free;
 
+	rdtgroup_assign_cntrs(rdtgrp);
+
 	kernfs_activate(rdtgrp->kn);
 
 	ret = rdtgroup_init_alloc(rdtgrp);
@@ -3918,6 +3967,7 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
 out_del_list:
 	list_del(&rdtgrp->rdtgroup_list);
 out_rmid_free:
+	rdtgroup_unassign_cntrs(rdtgrp);
 	mkdir_rdt_prepare_rmid_free(rdtgrp);
 out_closid_free:
 	closid_free(closid);
@@ -3988,6 +4038,9 @@ 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);
 
 	/*
@@ -4034,6 +4087,8 @@ 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);
 
-- 
2.34.1