Introduce the interface to modify assignments within a group when
"mbm_event" mode is enabled.
The assignment modifications are done in the following format:
<Event>:<Domain id>=<Assignment state>
Event: A valid MBM event in the
/sys/fs/resctrl/info/L3_MON/event_configs directory.
Domain ID: A valid domain ID. When writing, '*' applies the changes
to all domains.
Assignment states:
_ : Unassign the counter.
e : Assign the counter exclusively.
Examples:
$ cd /sys/fs/resctrl
$ cat /sys/fs/resctrl/mbm_L3_assignments
mbm_total_bytes:0=e;1=e
mbm_local_bytes:0=e;1=e
To unassign the counter associated with the mbm_total_bytes event on
domain 0:
$ echo "mbm_total_bytes:0=_" > mbm_L3_assignments
$ cat /sys/fs/resctrl/mbm_L3_assignments
mbm_total_bytes:0=_;1=e
mbm_local_bytes:0=e;1=e
To unassign the counter associated with the mbm_total_bytes event on
all the domains:
$ echo "mbm_total_bytes:*=_" > mbm_L3_assignments
$ cat /sys/fs/resctrl/mbm_L3_assignments
mbm_total_bytes:0=_;1=_
mbm_local_bytes:0=e;1=e
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v14: Fixed the problem reported by Peter.
Updated the changelog.
Updated the user doc resctrl.rst.
Added example section on how to use resctrl with mbm_assign_mode.
v13: Few changes in mbm_L3_assignments_write() after moving the event config to evt_list.
Resolved conflicts caused by the recent FS/ARCH code restructure.
v12: New patch:
Assignment interface moved inside the group based the discussion
https://lore.kernel.org/lkml/CALPaoCiii0vXOF06mfV=kVLBzhfNo0SFqt4kQGwGSGVUqvr2Dg@xxxxxxxxxxxxxx/#t
---
Documentation/filesystems/resctrl.rst | 146 +++++++++++++++++++++++-
fs/resctrl/internal.h | 9 ++
fs/resctrl/rdtgroup.c | 157 +++++++++++++++++++++++++-
3 files changed, 310 insertions(+), 2 deletions(-)
diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index a232a0b1356c..cd82c2966ed7 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -527,7 +527,8 @@ When the "mba_MBps" mount option is used all CTRL_MON groups will also contain:
Event: A valid MBM event in the
/sys/fs/resctrl/info/L3_MON/event_configs directory.
- Domain ID: A valid domain ID.
+ Domain ID: A valid domain ID. When writing, '*' applies the changes
+ to all domains.
Assignment states:
@@ -544,6 +545,34 @@ When the "mba_MBps" mount option is used all CTRL_MON groups will also contain:
mbm_total_bytes:0=e;1=e
mbm_local_bytes:0=e;1=e
+ Assignments can be modified by writing to the interface.
+
+ Example:
+ To unassign the counter associated with the mbm_total_bytes event on domain 0:
+ ::
+
+ # echo "mbm_total_bytes:0=_" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=_;1=e
+ mbm_local_bytes:0=e;1=e
+
+ To unassign the counter associated with the mbm_total_bytes event on all the domains:
+ ::
+
+ # echo "mbm_total_bytes:*=_" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=_;1=_
+ mbm_local_bytes:0=e;1=e
+
+ To assign the counter associated with the mbm_total_bytes event on all domains in
+ exclusive mode:
+ ::
+
+ # echo "mbm_total_bytes:*=e" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=e;1=e
+ mbm_local_bytes:0=e;1=e
+
Resource allocation rules
-------------------------
@@ -1579,6 +1608,121 @@ View the llc occupancy snapshot::
# cat /sys/fs/resctrl/p1/mon_data/mon_L3_00/llc_occupancy
11234000
+
+Examples on working with mbm_assign_mode
+========================================
+
+a. Check if MBM assign support is available
+::
+
+ #mount -t resctrl resctrl /sys/fs/resctrl/
+
+ # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
+ [mbm_event]
+ default
+
+mbm_event feature is detected and it is enabled.
+
+b. Check how many assignable counters are supported.
+::
+
+ # cat /sys/fs/resctrl/info/L3_MON/num_mbm_cntrs
+ 0=32;1=32
+
+c. Check how many assignable counters are available for assignment in each domain.
+::
+
+ # cat /sys/fs/resctrl/info/L3_MON/available_mbm_cntrs
+ 0=30;1=30
+
+d. To list the default group's assign states:
+::
+
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=e;1=e
+ mbm_local_bytes:0=e;1=e
+
+e. To unassign the counter associated with the mbm_total_bytes event on domain 0:
+::
+
+ # echo "mbm_total_bytes:0=_" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=_;1=e
+ mbm_local_bytes:0=e;1=e
+
+f. To unassign the counter associated with the mbm_total_bytes event on all domains:
+::
+
+ # echo "mbm_total_bytes:*=_" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignment
+ mbm_total_bytes:0=_;1=_
+ mbm_local_bytes:0=e;1=e
+
+g. To assign a counter associated with the mbm_total_bytes event on all domains i
+nexclusive mode:
+::
+
+ # echo "mbm_total_bytes:*=e" > /sys/fs/resctrl/mbm_L3_assignments
+ # cat /sys/fs/resctrl/mbm_L3_assignments
+ mbm_total_bytes:0=e;1=e
+ mbm_local_bytes:0=e;1=e
+
+h. Read the events mbm_total_bytes and mbm_local_bytes of the default group. There is
+no change in reading the events with the assignment. If the event is unassigned when
+reading, then the read will come back as "Unassigned".
+::
+
+ # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_total_bytes
+ 779247936
+ # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes
+ 765207488
+
+i. Check the default event configurations.
+::
+
+ # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_total_bytes/event_filter
+ local_reads,remote_reads,local_non_temporal_writes,remote_non_temporal_writes,
+ local_reads_slow_memory,remote_reads_slow_memory,dirty_victim_writes_all
+
+ # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_local_bytes/event_filter
+ local_reads,local_non_temporal_writes,local_reads_slow_memory
+
+j. Change the event configuration for mbm_local_bytes.
+::
+
+ # echo "local_reads, local_non_temporal_writes, local_reads_slow_memory, remote_reads" >
+ /sys/fs/resctrl/info/L3_MON/counter_configs/mbm_local_bytes/event_filter
+
+ # cat /sys/fs/resctrl/info/L3_MON/counter_configs/mbm_local_bytes/event_filter
+ local_reads, local_non_temporal_writes, local_reads_slow_memory, remote_reads
+
+This will update all (across all domains of all monitor groups) counter assignments
+associated with the mbm_local_bytes event.
+
+k. Now read the local event again. The first read may come back with "Unavailable"
+status. The subsequent read of mbm_local_bytes will display only the read events.
+::
+
+ # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes
+ Unavailable
+ # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes
+ 314101
+
+l. Users have the option to go back to 'default' mbm_assign_mode if required. This can be
+done using the following command. Note that switching the mbm_assign_mode will reset all
+the MBM counters (and thus all MBM events) of all the resctrl groups.
+::
+
+ # echo "default" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
+ # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
+ mbm_event
+ [default]
+
+m. Unmount the resctrl
+::
+
+ #umount /sys/fs/resctrl/
+
Intel RDT Errata
================
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index ed0e3b695ad5..14d99c723ea5 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -51,6 +51,15 @@ static inline struct rdt_fs_context *rdt_fc2context(struct fs_context *fc)
return container_of(kfc, struct rdt_fs_context, kfc);
}
+/*
+ * Assignment types for the monitor modes
+ */
+enum {
+ ASSIGN_NONE = 0,
+ ASSIGN_EXCLUSIVE,
+ ASSIGN_INVALID,
+};
+
/**
* struct mon_evt - Description of a monitor event
* @evtid: event id
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 18ec65801dbb..92bb8f3adfae 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -2129,6 +2129,160 @@ static int mbm_L3_assignments_show(struct kernfs_open_file *of, struct seq_file
return ret;
}
+/**
+ * mbm_get_mon_event_by_name() - Return the mon_evt entry for the matching
+ * event name.
+ */
+static struct mon_evt *mbm_get_mon_event_by_name(struct rdt_resource *r,
+ char *name)
+{
+ struct mon_evt *mevt;
+
+ for (mevt = &mon_event_all[0]; mevt < &mon_event_all[QOS_NUM_EVENTS]; mevt++) {
+ if (mevt->enabled && !strcmp(mevt->name, name))
+ return mevt;
+ }
+
+ return NULL;
+}
+
+static unsigned int resctrl_get_assign_state(char *assign)
+{
+ if (!assign || strlen(assign) != 1)
+ return ASSIGN_INVALID;
+
+ switch (*assign) {
+ case 'e':
+ return ASSIGN_EXCLUSIVE;
+ case '_':
+ return ASSIGN_NONE;
+ default:
+ return ASSIGN_INVALID;
+ }
+}
+
+static int resctrl_process_assign(struct rdt_resource *r, struct rdtgroup *rdtgrp,
+ char *event, char *tok)
+{
+ struct rdt_mon_domain *d;
+ unsigned long dom_id = 0;
+ char *dom_str, *id_str;
+ struct mon_evt *mevt;
+ int assign_state;
+ char domain[10];
+ bool found;
+ int ret;
+
+ mevt = mbm_get_mon_event_by_name(r, event);
+ if (!mevt) {
+ rdt_last_cmd_printf("Invalid event %s\n", event);
+ return -ENOENT;
+ }
+
+next:
+ if (!tok || tok[0] == '\0')
+ return 0;
+
+ /* Start processing the strings for each domain */
+ dom_str = strim(strsep(&tok, ";"));
+
+ id_str = strsep(&dom_str, "=");
+
+ /* Check for domain id '*' which means all domains */
+ if (id_str && *id_str == '*') {
+ d = NULL;
+ goto check_state;
+ } else if (!id_str || kstrtoul(id_str, 10, &dom_id)) {
+ rdt_last_cmd_puts("Missing domain id\n");
+ return -EINVAL;
+ }
+
+ /* Verify if the dom_id is valid */
+ found = false;
+ list_for_each_entry(d, &r->mon_domains, hdr.list) {
+ if (d->hdr.id == dom_id) {
+ found = true;
+ break;
+ }
+ }
+
+ if (!found) {
+ rdt_last_cmd_printf("Invalid domain id %ld\n", dom_id);
+ return -EINVAL;
+ }
+
+check_state:
+ assign_state = resctrl_get_assign_state(dom_str);
+
+ switch (assign_state) {
+ case ASSIGN_NONE:
+ ret = resctrl_unassign_cntr_event(r, d, rdtgrp, mevt);
+ break;
+ case ASSIGN_EXCLUSIVE:
+ ret = resctrl_assign_cntr_event(r, d, rdtgrp, mevt);
+ break;
+ case ASSIGN_INVALID:
+ ret = -EINVAL;
+ }
+
+ if (ret)
+ goto out_fail;
+
+ goto next;
+
+out_fail:
+ sprintf(domain, d ? "%ld" : "*", dom_id);
+
+ rdt_last_cmd_printf("Assign operation '%s:%s=%s' failed\n", event, domain, dom_str);
+
+ return ret;
+}
+
+static ssize_t mbm_L3_assignments_write(struct kernfs_open_file *of, char *buf,
+ size_t nbytes, loff_t off)
+{
+ struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
+ struct rdtgroup *rdtgrp;
+ char *token, *event;
+ int ret = 0;
+
+ /* Valid input requires a trailing newline */
+ if (nbytes == 0 || buf[nbytes - 1] != '\n')
+ return -EINVAL;
+
+ buf[nbytes - 1] = '\0';
+
+ rdtgrp = rdtgroup_kn_lock_live(of->kn);
+ if (!rdtgrp) {
+ rdtgroup_kn_unlock(of->kn);
+ return -ENOENT;
+ }
+ rdt_last_cmd_clear();
+
+ if (!resctrl_arch_mbm_cntr_assign_enabled(r)) {
+ rdt_last_cmd_puts("mbm_event mode is not enabled\n");
+ rdtgroup_kn_unlock(of->kn);
+ return -EINVAL;
+ }
+
+ while ((token = strsep(&buf, "\n")) != NULL) {
+ /*
+ * The write command follows the following format:
+ * “<Event>:<Domain ID>=<Assignment state>”
+ * Extract the event name first.
+ */
+ event = strsep(&token, ":");
+
+ ret = resctrl_process_assign(r, rdtgrp, event, token);
+ if (ret)
+ break;
+ }
+
+ rdtgroup_kn_unlock(of->kn);
+
+ return ret ?: nbytes;
+}
+
/* rdtgroup information files for one cache resource. */
static struct rftype res_common_files[] = {
{
@@ -2269,9 +2423,10 @@ static struct rftype res_common_files[] = {
},
{
.name = "mbm_L3_assignments",
- .mode = 0444,
+ .mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = mbm_L3_assignments_show,
+ .write = mbm_L3_assignments_write,
},
{
.name = "mbm_assign_mode",
--
2.34.1
