Introduce the interface to assign MBM events in mbm_cntr_assign mode.
Events can be enabled or disabled by writing to file
/sys/fs/resctrl/info/L3_MON/mbm_assign_control
Format is similar to the list format with addition of opcode for the
assignment operation.
"<CTRL_MON group>/<MON group>/<domain_id><opcode><flags>"
Format for specific type of groups:
* Default CTRL_MON group:
"//<domain_id><opcode><flags>"
* Non-default CTRL_MON group:
"<CTRL_MON group>//<domain_id><opcode><flags>"
* Child MON group of default CTRL_MON group:
"/<MON group>/<domain_id><opcode><flags>"
* Child MON group of non-default CTRL_MON group:
"<CTRL_MON group>/<MON group>/<domain_id><opcode><flags>"
Domain_id '*' will apply the flags on all the domains.
Opcode can be one of the following:
= Update the assignment to match the flags
+ Assign a new MBM event without impacting existing assignments.
- Unassign a MBM event from currently assigned events.
Assignment flags can be one of the following:
t MBM total event
l MBM local event
tl Both total and local MBM events
_ None of the MBM events. Valid only with '=' opcode.
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v7: Simplified the parsing (strsep(&token, "//") in rdtgroup_mbm_assign_control_write().
Added mutex lock in rdtgroup_mbm_assign_control_write() while processing.
Renamed rdtgroup_find_grp to rdtgroup_find_grp_by_name.
Fixed rdtgroup_str_to_mon_state to return error for invalid flags.
Simplified the calls rdtgroup_assign_cntr by merging few functions earlier.
Removed ABMC reference in FS code.
Reinette commented about handling the combination of flags like 'lt_' and '_lt'.
Not sure if we need to change the behaviour here. Processed them sequencially right now.
Users have the liberty to pass the flags. Restricting it might be a problem later.
v6: Added support assign all if domain id is '*'
Fixed the allocation of counter id if it not assigned already.
v5: Interface name changed from mbm_assign_control to mbm_control.
Fixed opcode and flags combination.
'=_" is valid.
"-_" amd "+_" is not valid.
Minor message update.
Renamed the function with prefix - rdtgroup_.
Corrected few documentation mistakes.
Rebase related changes after SNC support.
v4: Added domain specific assignments. Fixed the opcode parsing.
v3: New patch.
Addresses the feedback to provide the global assignment interface.
https://lore.kernel.org/lkml/c73f444b-83a1-4e9a-95d3-54c5165ee782@xxxxxxxxx/
---
Documentation/arch/x86/resctrl.rst | 94 +++++++++-
arch/x86/kernel/cpu/resctrl/internal.h | 10 ++
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 234 ++++++++++++++++++++++++-
3 files changed, 336 insertions(+), 2 deletions(-)
diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index a72cb3a6b07a..e46ec63d920e 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -334,7 +334,7 @@ with the following files:
t MBM total event is assigned.
l MBM local event is assigned.
tl Both total and local MBM events are assigned.
- _ None of the MBM events are assigned.
+ _ None of the MBM events are assigned. Only works with opcode '=' for write.
Examples:
::
@@ -352,6 +352,98 @@ with the following files:
There are four resctrl groups. All the groups have total and local MBM events
assigned on domain 0 and 1.
+ Assignment state can be updated by writing to the interface.
+
+ Format is similar to the list format with addition of opcode for the
+ assignment operation.
+
+ "<CTRL_MON group>/<MON group>/<domain_id><opcode><flags>"
+
+ Format for each type of groups:
+
+ * Default CTRL_MON group:
+ "//<domain_id><opcode><flags>"
+
+ * Non-default CTRL_MON group:
+ "<CTRL_MON group>//<domain_id><opcode><flags>"
+
+ * Child MON group of default CTRL_MON group:
+ "/<MON group>/<domain_id><opcode><flags>"
+
+ * Child MON group of non-default CTRL_MON group:
+ "<CTRL_MON group>/<MON group>/<domain_id><opcode><flags>"
+
+ Domain_id '*' will apply the flags on all the domains.
+
+ Opcode can be one of the following:
+ ::
+
+ = Update the assignment to match the MBM event.
+ + Assign a new MBM event without impacting existing assignments.
+ - Unassign a MBM event from currently assigned events.
+
+ Examples:
+ ::
+
+ Initial group status:
+ # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
+ non_default_ctrl_mon_grp//0=tl;1=tl;
+ non_default_ctrl_mon_grp/child_non_default_mon_grp/0=tl;1=tl;
+ //0=tl;1=tl;
+ /child_default_mon_grp/0=tl;1=tl;
+
+ To update the default group to assign only total MBM event on domain 0:
+ # echo "//0=t" > /sys/fs/resctrl/info/L3_MON/mbm_assign_control
+
+ Assignment status after the update:
+ # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
+ non_default_ctrl_mon_grp//0=tl;1=tl;
+ non_default_ctrl_mon_grp/child_non_default_mon_grp/0=tl;1=tl;
+ //0=t;1=tl;
+ /child_default_mon_grp/0=tl;1=tl;
+
+ To update the MON group child_default_mon_grp to remove total MBM event on domain 1:
+ # echo "/child_default_mon_grp/1-t" > /sys/fs/resctrl/info/L3_MON/mbm_assign_control
+
+ Assignment status after the update:
+ $ cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
+ non_default_ctrl_mon_grp//0=tl;1=tl;
+ non_default_ctrl_mon_grp/child_non_default_mon_grp/0=tl;1=tl;
+ //0=t;1=tl;
+ /child_default_mon_grp/0=tl;1=l;
+
+ To update the MON group non_default_ctrl_mon_grp/child_non_default_mon_grp to
+ unassign both local and total MBM events on domain 1:
+ # echo "non_default_ctrl_mon_grp/child_non_default_mon_grp/1=_" >
+ /sys/fs/resctrl/info/L3_MON/mbm_assign_control
+
+ Assignment status after the update:
+ non_default_ctrl_mon_grp//0=tl;1=tl;
+ non_default_ctrl_mon_grp/child_non_default_mon_grp/0=tl;1=_;
+ //0=t;1=tl;
+ /child_default_mon_grp/0=tl;1=l;
+
+ To update the default group to add a local MBM event domain 0.
+ # echo "//0+l" > /sys/fs/resctrl/info/L3_MON/mbm_assign_control
+
+ Assignment status after the update:
+ # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
+ non_default_ctrl_mon_grp//0=tl;1=tl;
+ non_default_ctrl_mon_grp/child_non_default_mon_grp/0=tl;1=_;
+ //0=tl;1=tl;
+ /child_default_mon_grp/0=tl;1=l;
+
+ To update the non default CTRL_MON group non_default_ctrl_mon_grp to unassign all
+ the MBM events on all the domains.
+ # echo "non_default_ctrl_mon_grp//*=_" > /sys/fs/resctrl/info/L3_MON/mbm_assign_control
+
+ Assignment status after the update:
+ #cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
+ non_default_ctrl_mon_grp//0=_;1=_;
+ non_default_ctrl_mon_grp/child_non_default_mon_grp/0=tl;1=_;
+ //0=tl;1=tl;
+ /child_default_mon_grp/0=tl;1=l;
+
"max_threshold_occupancy":
Read/write file provides the largest value (in
bytes) at which a previously used LLC_occupancy
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 3250561f0187..799f36eef2b6 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -67,6 +67,16 @@
#define MON_CNTR_UNSET U32_MAX
+/*
+ * Assignment flags for mbm_cntr_assign feature
+ */
+enum {
+ ASSIGN_NONE = 0,
+ ASSIGN_TOTAL = BIT(QOS_L3_MBM_TOTAL_EVENT_ID),
+ ASSIGN_LOCAL = BIT(QOS_L3_MBM_LOCAL_EVENT_ID),
+ ASSIGN_INVALID,
+};
+
/**
* cpumask_any_housekeeping() - Choose any CPU in @mask, preferring those that
* aren't marked nohz_full
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index ffa0ed98efbe..56ecdf7406ae 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1047,6 +1047,237 @@ static int rdtgroup_mbm_assign_control_show(struct kernfs_open_file *of,
return 0;
}
+static int rdtgroup_str_to_mon_state(char *flag)
+{
+ int i, mon_state = ASSIGN_NONE;
+
+ for (i = 0; i < strlen(flag); i++) {
+ switch (*(flag + i)) {
+ case 't':
+ mon_state |= ASSIGN_TOTAL;
+ break;
+ case 'l':
+ mon_state |= ASSIGN_LOCAL;
+ break;
+ case '_':
+ mon_state = ASSIGN_NONE;
+ break;
+ default:
+ return ASSIGN_INVALID;
+ }
+ }
+
+ return mon_state;
+}
+
+static struct rdtgroup *rdtgroup_find_grp_by_name(enum rdt_group_type rtype,
+ char *p_grp, char *c_grp)
+{
+ struct rdtgroup *rdtg, *crg;
+
+ if (rtype == RDTCTRL_GROUP && *p_grp == '\0') {
+ return &rdtgroup_default;
+ } else if (rtype == RDTCTRL_GROUP) {
+ list_for_each_entry(rdtg, &rdt_all_groups, rdtgroup_list)
+ if (!strcmp(p_grp, rdtg->kn->name))
+ return rdtg;
+ } else if (rtype == RDTMON_GROUP) {
+ list_for_each_entry(rdtg, &rdt_all_groups, rdtgroup_list) {
+ if (!strcmp(p_grp, rdtg->kn->name)) {
+ list_for_each_entry(crg, &rdtg->mon.crdtgrp_list,
+ mon.crdtgrp_list) {
+ if (!strcmp(c_grp, crg->kn->name))
+ return crg;
+ }
+ }
+ }
+ }
+
+ return NULL;
+}
+
+static int rdtgroup_process_flags(struct rdt_resource *r,
+ enum rdt_group_type rtype,
+ char *p_grp, char *c_grp, char *tok)
+{
+ int op, mon_state, assign_state, unassign_state;
+ char *dom_str, *id_str, *op_str;
+ struct rdt_mon_domain *d;
+ struct rdtgroup *rdtgrp;
+ unsigned long dom_id;
+ int ret, found = 0;
+
+ rdtgrp = rdtgroup_find_grp_by_name(rtype, p_grp, c_grp);
+
+ if (!rdtgrp) {
+ rdt_last_cmd_puts("Not a valid resctrl group\n");
+ return -EINVAL;
+ }
+
+next:
+ if (!tok || tok[0] == '\0')
+ return 0;
+
+ /* Start processing the strings for each domain */
+ dom_str = strim(strsep(&tok, ";"));
+
+ op_str = strpbrk(dom_str, "=+-");
+
+ if (op_str) {
+ op = *op_str;
+ } else {
+ rdt_last_cmd_puts("Missing operation =, +, -, _ character\n");
+ return -EINVAL;
+ }
+
+ 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 */
+ list_for_each_entry(d, &r->mon_domains, hdr.list) {
+ if (d->hdr.id == dom_id) {
+ found = 1;
+ break;
+ }
+ }
+
+ if (!found) {
+ rdt_last_cmd_printf("Invalid domain id %ld\n", dom_id);
+ return -EINVAL;
+ }
+
+check_state:
+ mon_state = rdtgroup_str_to_mon_state(dom_str);
+
+ if (mon_state == ASSIGN_INVALID) {
+ rdt_last_cmd_puts("Invalid assign flag\n");
+ goto out_fail;
+ }
+
+ assign_state = 0;
+ unassign_state = 0;
+
+ switch (op) {
+ case '+':
+ if (mon_state == ASSIGN_NONE) {
+ rdt_last_cmd_puts("Invalid assign opcode\n");
+ goto out_fail;
+ }
+ assign_state = mon_state;
+ break;
+ case '-':
+ if (mon_state == ASSIGN_NONE) {
+ rdt_last_cmd_puts("Invalid assign opcode\n");
+ goto out_fail;
+ }
+ unassign_state = mon_state;
+ break;
+ case '=':
+ assign_state = mon_state;
+ unassign_state = (ASSIGN_TOTAL | ASSIGN_LOCAL) & ~assign_state;
+ break;
+ default:
+ break;
+ }
+
+ if (assign_state & ASSIGN_TOTAL) {
+ ret = rdtgroup_assign_cntr(r, rdtgrp, d, QOS_L3_MBM_TOTAL_EVENT_ID);
+ if (ret)
+ goto out_fail;
+ }
+
+ if (assign_state & ASSIGN_LOCAL) {
+ ret = rdtgroup_assign_cntr(r, rdtgrp, d, QOS_L3_MBM_LOCAL_EVENT_ID);
+ if (ret)
+ goto out_fail;
+ }
+
+ if (unassign_state & ASSIGN_TOTAL) {
+ ret = rdtgroup_unassign_cntr(r, rdtgrp, d, QOS_L3_MBM_TOTAL_EVENT_ID);
+ if (ret)
+ goto out_fail;
+ }
+
+ if (unassign_state & ASSIGN_LOCAL) {
+ ret = rdtgroup_unassign_cntr(r, rdtgrp, d, QOS_L3_MBM_LOCAL_EVENT_ID);
+ if (ret)
+ goto out_fail;
+ }
+
+ goto next;
+
+out_fail:
+
+ return -EINVAL;
+}
+
+static ssize_t rdtgroup_mbm_assign_control_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct rdt_resource *r = of->kn->parent->priv;
+ char *token, *cmon_grp, *mon_grp;
+ enum rdt_group_type rtype;
+ int ret;
+
+ /* Valid input requires a trailing newline */
+ if (nbytes == 0 || buf[nbytes - 1] != '\n')
+ return -EINVAL;
+
+ buf[nbytes - 1] = '\0';
+
+ cpus_read_lock();
+ mutex_lock(&rdtgroup_mutex);
+
+ if (!resctrl_arch_mbm_cntr_assign_enabled(r)) {
+ rdt_last_cmd_puts("mbm_cntr_assign mode is not enabled\n");
+ mutex_unlock(&rdtgroup_mutex);
+ cpus_read_unlock();
+ return -EINVAL;
+ }
+
+ rdt_last_cmd_clear();
+
+ while ((token = strsep(&buf, "\n")) != NULL) {
+ if (strstr(token, "/")) {
+ /*
+ * The write command follows the following format:
+ * “<CTRL_MON group>/<MON group>/<domain_id><opcode><flags>”
+ * Extract the CTRL_MON group.
+ */
+ cmon_grp = strsep(&token, "/");
+
+ /*
+ * Extract the MON_GROUP.
+ * strsep returns empty string for contiguous delimiters.
+ * Empty mon_grp here means it is a RDTCTRL_GROUP.
+ */
+ mon_grp = strsep(&token, "/");
+
+ if (*mon_grp == '\0')
+ rtype = RDTCTRL_GROUP;
+ else
+ rtype = RDTMON_GROUP;
+
+ ret = rdtgroup_process_flags(r, rtype, cmon_grp, mon_grp, token);
+ if (ret)
+ break;
+ }
+ }
+
+ mutex_unlock(&rdtgroup_mutex);
+ cpus_read_unlock();
+
+ return ret ?: nbytes;
+}
+
#ifdef CONFIG_PROC_CPU_RESCTRL
/*
@@ -2315,9 +2546,10 @@ static struct rftype res_common_files[] = {
},
{
.name = "mbm_assign_control",
- .mode = 0444,
+ .mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdtgroup_mbm_assign_control_show,
+ .write = rdtgroup_mbm_assign_control_write,
},
{
.name = "cpus_list",
--
2.34.1
