fs/resctrl: Support counter read/reset with mbm_event assignment mode

When "mbm_event" counter assignment mode is enabled, the architecture requires
a counter ID to read the event data.

Introduce an is_mbm_cntr field in struct rmid_read to indicate whether counter
assignment mode is in use.

Update the logic to call resctrl_arch_cntr_read() and resctrl_arch_reset_cntr()
when the assignment mode is active. Report 'Unassigned' in case the user attempts
to read an event without assigning a hardware counter.

Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
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/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index 446736dbd97f1943ead365a47ef85708a829145e..4c24c5f3f4c1960a2eb396fef2419fa63d1a59b6 100644 (file)
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -434,6 +434,12 @@ When monitoring is enabled all MON groups will also contain:
        for the L3 cache they occupy). These are named "mon_sub_L3_YY"
        where "YY" is the node number.
 
+       When the 'mbm_event' counter assignment mode is enabled, reading
+       an MBM event of a MON group returns 'Unassigned' if no hardware
+       counter is assigned to it. For CTRL_MON groups, 'Unassigned' is
+       returned if the MBM event does not have an assigned counter in the
+       CTRL_MON group nor in any of its associated MON groups.
+
 "mon_hw_id":
        Available only with debug option. The identifier used by hardware
        for the monitor group. On x86 this is the RMID.

diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index 42b281b3852ff838994a17af958541e6edb64e16..0d0ef54fc4de1fed2d38548c76dfd779ae1672c0 100644 (file)
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -563,10 +563,15 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
        rr->r = r;
        rr->d = d;
        rr->first = first;
-       rr->arch_mon_ctx = resctrl_arch_mon_ctx_alloc(r, evtid);
-       if (IS_ERR(rr->arch_mon_ctx)) {
-               rr->err = -EINVAL;
-               return;
+       if (resctrl_arch_mbm_cntr_assign_enabled(r) &&
+           resctrl_is_mbm_event(evtid)) {
+               rr->is_mbm_cntr = true;
+       } else {
+               rr->arch_mon_ctx = resctrl_arch_mon_ctx_alloc(r, evtid);
+               if (IS_ERR(rr->arch_mon_ctx)) {
+                       rr->err = -EINVAL;
+                       return;
+               }
        }
 
        cpu = cpumask_any_housekeeping(cpumask, RESCTRL_PICK_ANY_CPU);
@@ -582,7 +587,8 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
        else
                smp_call_on_cpu(cpu, smp_mon_event_count, rr, false);
 
-       resctrl_arch_mon_ctx_free(r, evtid, rr->arch_mon_ctx);
+       if (rr->arch_mon_ctx)
+               resctrl_arch_mon_ctx_free(r, evtid, rr->arch_mon_ctx);
 }
 
 int rdtgroup_mondata_show(struct seq_file *m, void *arg)
@@ -653,10 +659,16 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
 
 checkresult:
 
+       /*
+        * -ENOENT is a special case, set only when "mbm_event" counter assignment
+        * mode is enabled and no counter has been assigned.
+        */
        if (rr.err == -EIO)
                seq_puts(m, "Error\n");
        else if (rr.err == -EINVAL)
                seq_puts(m, "Unavailable\n");
+       else if (rr.err == -ENOENT)
+               seq_puts(m, "Unassigned\n");
        else
                seq_printf(m, "%llu\n", rr.val);
 

diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index c6b66d4a6a375fb4422e69f4072cf81da45d7092..2f1f2efe2f40f1f755e713e5c54d4ada0a001cd0 100644 (file)
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -111,6 +111,8 @@ struct mon_data {
  * @evtid: Which monitor event to read.
  * @first: Initialize MBM counter when true.
  * @ci:    Cacheinfo for L3. Only set when @d is NULL. Used when summing domains.
+ * @is_mbm_cntr: true if "mbm_event" counter assignment mode is enabled and it
+ *        is an MBM event.
  * @err:   Error encountered when reading counter.
  * @val:   Returned value of event counter. If @rgrp is a parent resource group,
  *        @val includes the sum of event counts from its child resource groups.
@@ -125,6 +127,7 @@ struct rmid_read {
        enum resctrl_event_id   evtid;
        bool                    first;
        struct cacheinfo        *ci;
+       bool                    is_mbm_cntr;
        int                     err;
        u64                     val;
        void                    *arch_mon_ctx;

diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index c815153cad074c7a909f9a38072ecc7d905eec94..55327056596ee2d28ffd2fea8a794866d28ccbe6 100644 (file)
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -419,12 +419,24 @@ static int __mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr)
        u32 closid = rdtgrp->closid;
        u32 rmid = rdtgrp->mon.rmid;
        struct rdt_mon_domain *d;
+       int cntr_id = -ENOENT;
        struct mbm_state *m;
        int err, ret;
        u64 tval = 0;
 
+       if (rr->is_mbm_cntr) {
+               cntr_id = mbm_cntr_get(rr->r, rr->d, rdtgrp, rr->evtid);
+               if (cntr_id < 0) {
+                       rr->err = -ENOENT;
+                       return -EINVAL;
+               }
+       }
+
        if (rr->first) {
-               resctrl_arch_reset_rmid(rr->r, rr->d, closid, rmid, rr->evtid);
+               if (rr->is_mbm_cntr)
+                       resctrl_arch_reset_cntr(rr->r, rr->d, closid, rmid, cntr_id, rr->evtid);
+               else
+                       resctrl_arch_reset_rmid(rr->r, rr->d, closid, rmid, rr->evtid);
                m = get_mbm_state(rr->d, closid, rmid, rr->evtid);
                if (m)
                        memset(m, 0, sizeof(struct mbm_state));
@@ -435,8 +447,12 @@ static int __mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr)
                /* Reading a single domain, must be on a CPU in that domain. */
                if (!cpumask_test_cpu(cpu, &rr->d->hdr.cpu_mask))
                        return -EINVAL;
-               rr->err = resctrl_arch_rmid_read(rr->r, rr->d, closid, rmid,
-                                                rr->evtid, &tval, rr->arch_mon_ctx);
+               if (rr->is_mbm_cntr)
+                       rr->err = resctrl_arch_cntr_read(rr->r, rr->d, closid, rmid, cntr_id,
+                                                        rr->evtid, &tval);
+               else
+                       rr->err = resctrl_arch_rmid_read(rr->r, rr->d, closid, rmid,
+                                                        rr->evtid, &tval, rr->arch_mon_ctx);
                if (rr->err)
                        return rr->err;
 
@@ -460,8 +476,12 @@ static int __mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr)
        list_for_each_entry(d, &rr->r->mon_domains, hdr.list) {
                if (d->ci_id != rr->ci->id)
                        continue;
-               err = resctrl_arch_rmid_read(rr->r, d, closid, rmid,
-                                            rr->evtid, &tval, rr->arch_mon_ctx);
+               if (rr->is_mbm_cntr)
+                       err = resctrl_arch_cntr_read(rr->r, d, closid, rmid, cntr_id,
+                                                    rr->evtid, &tval);
+               else
+                       err = resctrl_arch_rmid_read(rr->r, d, closid, rmid,
+                                                    rr->evtid, &tval, rr->arch_mon_ctx);
                if (!err) {
                        rr->val += tval;
                        ret = 0;
@@ -668,11 +688,15 @@ static void mbm_update_one_event(struct rdt_resource *r, struct rdt_mon_domain *
        rr.r = r;
        rr.d = d;
        rr.evtid = evtid;
-       rr.arch_mon_ctx = resctrl_arch_mon_ctx_alloc(rr.r, rr.evtid);
-       if (IS_ERR(rr.arch_mon_ctx)) {
-               pr_warn_ratelimited("Failed to allocate monitor context: %ld",
-                                   PTR_ERR(rr.arch_mon_ctx));
-               return;
+       if (resctrl_arch_mbm_cntr_assign_enabled(r)) {
+               rr.is_mbm_cntr = true;
+       } else {
+               rr.arch_mon_ctx = resctrl_arch_mon_ctx_alloc(rr.r, rr.evtid);
+               if (IS_ERR(rr.arch_mon_ctx)) {
+                       pr_warn_ratelimited("Failed to allocate monitor context: %ld",
+                                           PTR_ERR(rr.arch_mon_ctx));
+                       return;
+               }
        }
 
        __mon_event_count(rdtgrp, &rr);
@@ -684,7 +708,8 @@ static void mbm_update_one_event(struct rdt_resource *r, struct rdt_mon_domain *
        if (is_mba_sc(NULL))
                mbm_bw_count(rdtgrp, &rr);
 
-       resctrl_arch_mon_ctx_free(rr.r, rr.evtid, rr.arch_mon_ctx);
+       if (rr.arch_mon_ctx)
+               resctrl_arch_mon_ctx_free(rr.r, rr.evtid, rr.arch_mon_ctx);
 }
 
 static void mbm_update(struct rdt_resource *r, struct rdt_mon_domain *d,