Hi, Tony,
On 10/29/24 10:28, Tony Luck wrote:
A user can choose any of the memory bandwidth monitoring events
listed in /sys/fs/resctrl/info/L3_mon/mon_features independently
for each ctrl_mon group by writing to the "mba_MBps_event" file.
Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
---
arch/x86/kernel/cpu/resctrl/internal.h | 2 +
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 46 +++++++++++++++++++++++
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 1 +
3 files changed, 49 insertions(+)
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 5f3438ca9e2b..35483c6615b6 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -609,6 +609,8 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off);
int rdtgroup_schemata_show(struct kernfs_open_file *of,
struct seq_file *s, void *v);
+ssize_t rdtgroup_mba_mbps_event_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off);
int rdtgroup_mba_mbps_event_show(struct kernfs_open_file *of,
struct seq_file *s, void *v);
bool rdtgroup_cbm_overlaps(struct resctrl_schema *s, struct rdt_ctrl_domain *d,
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index b9ba419e5c88..fc5585dc688f 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -518,6 +518,52 @@ static int smp_mon_event_count(void *arg)
return 0;
}
+ssize_t rdtgroup_mba_mbps_event_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct rdtgroup *rdtgrp;
+ 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 (!strcmp(buf, "mbm_local_bytes")) {
+ if (is_mbm_local_enabled())
+ rdtgrp->mba_mbps_event = QOS_L3_MBM_LOCAL_EVENT_ID;
+ else
+ ret = -ENXIO;
+ } else if (!strcmp(buf, "mbm_total_bytes")) {
+ if (is_mbm_total_enabled())
+ rdtgrp->mba_mbps_event = QOS_L3_MBM_TOTAL_EVENT_ID;
User may think each time toggling the local/total event will effect MBA.
And they may create usage case like frequently changing the events to
maintain/adjust both total and local within bw boundary.
But toggling mba_mbps_event faster than 1sec doesn't have any effect on
MBA SC because MBA SC is called every one second.
Maybe need to add a ratelimit of 1 second on calling this function? And
adding info in the document that toggling speed should be slower than 1
second?
+ else
+ ret = -ENXIO;
+ } else {
+ ret = -EINVAL;
+ }
+
+ switch (ret) {
+ case -ENXIO:
+ rdt_last_cmd_printf("Unsupported event id '%s'\n", buf);
+ break;
+ case -EINVAL:
+ rdt_last_cmd_printf("Unknown event id '%s'\n", buf);
+ break;
+ }
+
+ rdtgroup_kn_unlock(of->kn);
+
+ return ret ?: nbytes;
+}
+
int rdtgroup_mba_mbps_event_show(struct kernfs_open_file *of,
struct seq_file *s, void *v)
{
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 3ba81963e981..6fa501ef187f 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1947,6 +1947,7 @@ static struct rftype res_common_files[] = {
.name = "mba_MBps_event",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
+ .write = rdtgroup_mba_mbps_event_write,
.seq_show = rdtgroup_mba_mbps_event_show,
},
{
Thanks.
-Fenghua
