Hi, Babu,
On 10/29/24 16:21, Babu Moger wrote:
The mbm_cntr_assign mode offers several hardware counters that can be
assigned to an RMID, event pair and monitor the bandwidth as long as it
is assigned.
Counters are managed at two levels. The global assignment is tracked
using the mbm_cntr_free_map field in the struct resctrl_mon, while
domain-specific assignments are tracked using the mbm_cntr_map field
in the struct rdt_mon_domain. Allocation begins at the global level
and is then applied individually to each domain.
Introduce an interface to allocate these counters and update the
corresponding domains accordingly.
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v9: Introduced new function resctrl_config_cntr to assign the counter, update
the bitmap and reset the architectural state.
Taken care of error handling(freeing the counter) when assignment fails.
Moved mbm_cntr_assigned_to_domain here as it used in this patch.
Minor text changes.
v8: Renamed rdtgroup_assign_cntr() to rdtgroup_assign_cntr_event().
Added the code to return the error if rdtgroup_assign_cntr_event fails.
Moved definition of MBM_EVENT_ARRAY_INDEX to resctrl/internal.h.
Updated typo in the comments.
v7: New patch. Moved all the FS code here.
Merged rdtgroup_assign_cntr and rdtgroup_alloc_cntr.
Adde new #define MBM_EVENT_ARRAY_INDEX.
---
arch/x86/kernel/cpu/resctrl/internal.h | 2 +
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 87 ++++++++++++++++++++++++++
2 files changed, 89 insertions(+)
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 00f7bf60e16a..cb496bd97007 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -717,6 +717,8 @@ unsigned int mon_event_config_index_get(u32 evtid);
int resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
enum resctrl_event_id evtid, u32 rmid, u32 closid,
u32 cntr_id, bool assign);
+int rdtgroup_assign_cntr_event(struct rdt_resource *r, struct rdtgroup *rdtgrp,
+ struct rdt_mon_domain *d, enum resctrl_event_id evtid);
void rdt_staged_configs_clear(void);
bool closid_allocated(unsigned int closid);
int resctrl_find_cleanest_closid(void);
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 1b5529c212f5..bc3752967c44 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1924,6 +1924,93 @@ int resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
return 0;
}
+/*
+ * Configure the counter for the event, RMID pair for the domain.
+ * Update the bitmap and reset the architectural state.
+ */
+static int resctrl_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
+ enum resctrl_event_id evtid, u32 rmid, u32 closid,
+ u32 cntr_id, bool assign)
+{
+ int ret;
+
+ ret = resctrl_arch_config_cntr(r, d, evtid, rmid, closid, cntr_id, assign);
+ if (ret)
+ return ret;
+
+ if (assign)
+ __set_bit(cntr_id, d->mbm_cntr_map);
+ else
+ __clear_bit(cntr_id, d->mbm_cntr_map);
+
+ /*
+ * Reset the architectural state so that reading of hardware
+ * counter is not considered as an overflow in next update.
+ */
+ resctrl_arch_reset_rmid(r, d, closid, rmid, evtid);
+
+ return ret;
+}
+
+static bool mbm_cntr_assigned_to_domain(struct rdt_resource *r, u32 cntr_id)
+{
+ struct rdt_mon_domain *d;
+
+ list_for_each_entry(d, &r->mon_domains, hdr.list)
+ if (test_bit(cntr_id, d->mbm_cntr_map))
+ return 1;
+
+ return 0;
+}
+
+/*
+ * Assign a hardware counter to event @evtid of group @rdtgrp.
+ * Counter will be assigned to all the domains if rdt_mon_domain is NULL
+ * else the counter will be assigned to specific domain.
+ */
+int rdtgroup_assign_cntr_event(struct rdt_resource *r, struct rdtgroup *rdtgrp,
+ struct rdt_mon_domain *d, enum resctrl_event_id evtid)
+{
+ int index = MBM_EVENT_ARRAY_INDEX(evtid);
+ int cntr_id = rdtgrp->mon.cntr_id[index];
+ int ret;
+
+ /*
+ * Allocate a new counter id to the event if the counter is not
+ * assigned already.
+ */
+ if (cntr_id == MON_CNTR_UNSET) {
+ cntr_id = mbm_cntr_alloc(r);
+ if (cntr_id < 0) {
+ rdt_last_cmd_puts("Out of MBM assignable counters\n");
+ return -ENOSPC;
+ }
+ rdtgrp->mon.cntr_id[index] = cntr_id;
+ }
+
+ if (!d) {
Should assert cpus are locked here?
/* Walking r->domains, ensure it can't race with cpuhp */
lockdep_assert_cpus_held();
Please see more comments on patch #20.
+ list_for_each_entry(d, &r->mon_domains, hdr.list) {
+ ret = resctrl_config_cntr(r, d, evtid, rdtgrp->mon.rmid,
+ rdtgrp->closid, cntr_id, true);
+ if (ret)
+ goto out_done_assign;
+ }
+ } else {
+ ret = resctrl_config_cntr(r, d, evtid, rdtgrp->mon.rmid,
+ rdtgrp->closid, cntr_id, true);
+ if (ret)
+ goto out_done_assign;
+ }
+
+out_done_assign:
+ if (ret && !mbm_cntr_assigned_to_domain(r, cntr_id)) {
+ mbm_cntr_free(r, cntr_id);
+ rdtgroup_cntr_id_init(rdtgrp, evtid);
+ }
+
+ return ret;
+}
+
/* rdtgroup information files for one cache resource. */
static struct rftype res_common_files[] = {
{
Thanks.
-Fenghua
