When supported "mbm_event" mode offers "num_mbm_cntrs" number of counters
that can be assigned to RMID, event pairs and monitor bandwidth usage as
long as it is assigned.
Add the functionality to allocate and assign a counter ID to an RMID, event
pair in the domain.
If all the counters are in use, kernel will log the error message "Unable
to allocate counter in domain" in /sys/fs/resctrl/info/last_cmd_status
when a new assignment is requested. Exit on the first failure when
assigning counters across all the domains.
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v14: Updated the changelog little bit.
Updated the code documentation for mbm_cntr_alloc() and mbm_cntr_get().
Passed struct mon_evt to resctrl_assign_cntr_event() that way to avoid
back and forth calls to get event details.
Updated the code documentation about the failure when counters are exhasted.
Changed subject line to fs/resctrl.
v13: Updated changelog.
Changed resctrl_arch_config_cntr() to return void instead of int.
Just passing evtid is to resctrl_alloc_config_cntr() and
resctrl_assign_cntr_event(). Event configuration value can be easily
obtained from mon_evt list.
Introduced new function mbm_get_mon_event() to get event configuration value.
Added prototype descriptions to mbm_cntr_get() and mbm_cntr_alloc().
Resolved conflicts caused by the recent FS/ARCH code restructure.
The files monitor.c/rdtgroup.c have been split between FS and ARCH directories.
v12: Fixed typo in the subjest line.
Replaced several counters with "num_mbm_cntrs" counters.
Changed the check in resctrl_alloc_config_cntr() to reduce the indentation.
Fixed the handling error on first failure.
Added domain id and event id on failure.
Fixed the return error override.
Added new parameter event configuration (evt_cfg) to get the event configuration
from user space.
v11: Patch changed again quite a bit.
Moved the functions to monitor.c.
Renamed rdtgroup_assign_cntr_event() to resctrl_assign_cntr_event().
Refactored the resctrl_assign_cntr_event().
Added functionality to exit on the first error during assignment.
Simplified mbm_cntr_free().
Removed the function mbm_cntr_assigned(). Will be using mbm_cntr_get() to
figure out if the counter is assigned or not.
Updated commit message and code comments.
v10: Patch changed completely.
Counters are managed at the domain based on the discussion.
https://lore.kernel.org/lkml/CALPaoCj+zWq1vkHVbXYP0znJbe6Ke3PXPWjtri5AFgD9cQDCUg@xxxxxxxxxxxxxx/
Reset non-architectural MBM state.
Commit message update.
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.
---
fs/resctrl/internal.h | 3 +
fs/resctrl/monitor.c | 134 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 137 insertions(+)
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index 71059c2cda16..0767a1c46f26 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -386,6 +386,9 @@ bool closid_allocated(unsigned int closid);
int resctrl_find_cleanest_closid(void);
+int resctrl_assign_cntr_event(struct rdt_resource *r, struct rdt_mon_domain *d,
+ struct rdtgroup *rdtgrp, struct mon_evt *mevt);
+
#ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK
int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp);
diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index 3e1a8239b0d3..38800fe45931 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -950,3 +950,137 @@ void resctrl_mon_resource_exit(void)
dom_data_exit(r);
}
+
+/**
+ * resctrl_config_cntr() - Configure the counter ID for the event, RMID pair in
+ * the domain.
+ *
+ * Assign the counter if @assign is true else unassign the counter. Reset the
+ * associated non-architectural state.
+ */
+static void 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)
+{
+ struct mbm_state *m;
+
+ resctrl_arch_config_cntr(r, d, evtid, rmid, closid, cntr_id, assign);
+
+ m = get_mbm_state(d, closid, rmid, evtid);
+ if (m)
+ memset(m, 0, sizeof(struct mbm_state));
+}
+
+/**
+ * mbm_cntr_get() - Return the counter ID for the matching @evtid and @rdtgrp.
+ *
+ * Return:
+ * Valid counter ID on success, or -ENOENT on failure.
+ */
+static int mbm_cntr_get(struct rdt_resource *r, struct rdt_mon_domain *d,
+ struct rdtgroup *rdtgrp, enum resctrl_event_id evtid)
+{
+ int cntr_id;
+
+ if (!resctrl_is_mbm_event(evtid))
+ return -ENOENT;
+
+ for (cntr_id = 0; cntr_id < r->mon.num_mbm_cntrs; cntr_id++) {
+ if (d->cntr_cfg[cntr_id].rdtgrp == rdtgrp &&
+ d->cntr_cfg[cntr_id].evtid == evtid)
+ return cntr_id;
+ }
+
+ return -ENOENT;
+}
+
+/**
+ * mbm_cntr_alloc() - Initilialize and return a new counter ID in the domain @d.
+ *
+ * Return:
+ * Valid counter ID on success, or -ENOSPC on failure.
+ */
+static int mbm_cntr_alloc(struct rdt_resource *r, struct rdt_mon_domain *d,
+ struct rdtgroup *rdtgrp, enum resctrl_event_id evtid)
+{
+ int cntr_id;
+
+ for (cntr_id = 0; cntr_id < r->mon.num_mbm_cntrs; cntr_id++) {
+ if (!d->cntr_cfg[cntr_id].rdtgrp) {
+ d->cntr_cfg[cntr_id].rdtgrp = rdtgrp;
+ d->cntr_cfg[cntr_id].evtid = evtid;
+ return cntr_id;
+ }
+ }
+
+ return -ENOSPC;
+}
+
+/**
+ * resctrl_alloc_config_cntr() - Allocate a counter ID and configure it for the
+ * event pointed to by @mevt and the resctrl group @rdtgrp within the domain @d.
+ *
+ * Return:
+ * 0 on success, or a non-zero value on failure.
+ */
+static int resctrl_alloc_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
+ struct rdtgroup *rdtgrp, struct mon_evt *mevt)
+{
+ int cntr_id;
+
+ /* No need to allocate a new counter if it is already assigned */
+ cntr_id = mbm_cntr_get(r, d, rdtgrp, mevt->evtid);
+ if (cntr_id >= 0)
+ goto cntr_configure;
+
+ cntr_id = mbm_cntr_alloc(r, d, rdtgrp, mevt->evtid);
+ if (cntr_id < 0) {
+ rdt_last_cmd_printf("Unable to allocate counter in domain %d\n",
+ d->hdr.id);
+ return cntr_id;
+ }
+
+cntr_configure:
+ /*
+ * Skip reconfiguration if the event setup is current; otherwise,
+ * update and apply the new configuration to the domain.
+ */
+ if (mevt->evt_cfg != d->cntr_cfg[cntr_id].evt_cfg) {
+ d->cntr_cfg[cntr_id].evt_cfg = mevt->evt_cfg;
+ resctrl_config_cntr(r, d, mevt->evtid, rdtgrp->mon.rmid,
+ rdtgrp->closid, cntr_id, true);
+ }
+
+ return 0;
+}
+
+/**
+ * resctrl_assign_cntr_event() - Assign a hardware counter for the event in
+ * @mevt to the resctrl group @rdtgrp. Assign counters to all domains if @d is
+ * NULL; otherwise, assign the counter to the specified domain @d.
+ *
+ * If all counters in a domain are already in use, resctrl_alloc_config_cntr()
+ * will fail. The assignment process will abort at the first failure encountered
+ * during domain traversal, which may result in the event being only partially
+ * assigned.
+ *
+ * Return:
+ * 0 on success, or a non-zero value on failure.
+ */
+int resctrl_assign_cntr_event(struct rdt_resource *r, struct rdt_mon_domain *d,
+ struct rdtgroup *rdtgrp, struct mon_evt *mevt)
+{
+ int ret = 0;
+
+ if (!d) {
+ list_for_each_entry(d, &r->mon_domains, hdr.list) {
+ ret = resctrl_alloc_config_cntr(r, d, rdtgrp, mevt);
+ if (ret)
+ return ret;
+ }
+ } else {
+ ret = resctrl_alloc_config_cntr(r, d, rdtgrp, mevt);
+ }
+
+ return ret;
+}
--
2.34.1
