Hi Babu,
On 8/6/24 3:00 PM, Babu Moger wrote:
Introduce the interface to assign MBM events in ABMC mode.
Events can be enabled or disabled by writing to file
/sys/fs/resctrl/info/L3_MON/mbm_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 MBM event
- unassign a MBM event
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.
(please note comments in this area of cover letter)
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
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 | 7 +
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 315 ++++++++++++++++++++++++-
3 files changed, 414 insertions(+), 2 deletions(-)
diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index 113c22ba6db3..ae3b17b7cefe 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -346,7 +346,7 @@ with the following files:
t MBM total event is enabled.
l MBM local event is enabled.
tl Both total and local MBM events are enabled.
- _ None of the MBM events are enabled.
+ _ None of the MBM events are enabled. Only works with opcode '=' for write.
Examples:
::
@@ -365,6 +365,98 @@ with the following files:
enabled 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 '*' wil apply the flags on all the domains.
+
+ Opcode can be one of the following:
+ ::
+
+ = Update the assignment to match the MBM event.
+ + Assign a MBM event.
"Assign a new MBM event without impacting existing assignments."?
+ - Unassign a MBM event.
(similar)
+
+ Examples:
+ ::
+
+ Initial group status:
+ # cat /sys/fs/resctrl/info/L3_MON/mbm_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_control
+
+ Assignment status after the update:
+ # cat /sys/fs/resctrl/info/L3_MON/mbm_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_control
+
+ Assignment status after the update:
+ $ cat /sys/fs/resctrl/info/L3_MON/mbm_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_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_control
+
+ Assignment status after the update:
+ # cat /sys/fs/resctrl/info/L3_MON/mbm_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_control
+
+ Assignment status after the update:
+ #cat /sys/fs/resctrl/info/L3_MON/mbm_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 ba3012f8f940..5af225b4a497 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -46,6 +46,13 @@
#define MON_CNTR_UNSET U32_MAX
+/*
+ * Assignment flags for ABMC feature
(this is resctrl fs code)
+ */
+#define ASSIGN_NONE 0
+#define ASSIGN_TOTAL BIT(QOS_L3_MBM_TOTAL_EVENT_ID)
+#define ASSIGN_LOCAL BIT(QOS_L3_MBM_LOCAL_EVENT_ID)
+
/**
* 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 d7aadca5e4ab..8567fb3a6274 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1034,6 +1034,318 @@ static int rdtgroup_mbm_control_show(struct kernfs_open_file *of,
return 0;
}
+/*
+ * Update the assign states for the domain.
+ *
+ * If this is a new assignment for the group then allocate a counter and update
+ * the assignment else just update the assign state
+ */
+static int rdtgroup_assign_update(struct rdtgroup *rdtgrp, enum resctrl_event_id evtid,
+ struct rdt_mon_domain *d)
+{
+ int ret, index;
+
+ index = mon_event_config_index_get(evtid);
+ if (index == INVALID_CONFIG_INDEX)
+ return -EINVAL;
(wrong spacing ... see checkpatch.pl)
+
+ if (rdtgrp->mon.cntr_id[index] == MON_CNTR_UNSET) {
+ ret = rdtgroup_alloc_cntr(rdtgrp, index);
+ if (ret < 0)
+ goto out_done;
+ }
+
+ /* Update the state on all domains if d == NULL */
+ if (d == NULL) {
if (!d) ... (checkpatch)
+ ret = rdtgroup_assign_cntr(rdtgrp, evtid);
+ } else {
+ ret = resctrl_arch_assign_cntr(d, evtid, rdtgrp->mon.rmid,
+ rdtgrp->mon.cntr_id[index],
+ rdtgrp->closid, 1);
+ if (!ret)
+ set_bit(rdtgrp->mon.cntr_id[index], d->mbm_cntr_map);
+ }
+
+out_done:
+ return ret;
+}
Please merge this with almost identical rdtgroup_assign_cntr()
+
+/*
+ * Update the unassign state for the domain.
+ *
+ * Free the counter if it is unassigned on all the domains else just
+ * update the unassign state
+ */
+static int rdtgroup_unassign_update(struct rdtgroup *rdtgrp, enum resctrl_event_id evtid,
+ struct rdt_mon_domain *d)
+{
+ struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+ int ret = 0, index;
+
+ index = mon_event_config_index_get(evtid);
+ if (index == INVALID_CONFIG_INDEX)
+ return -EINVAL;
(wrong spacing ... see checkpatch.pl)
+
+ if (rdtgrp->mon.cntr_id[index] == MON_CNTR_UNSET)
+ goto out_done;
+
+ if (d == NULL) {
if (!d)
+ ret = rdtgroup_unassign_cntr(rdtgrp, evtid);
+ } else {
+ ret = resctrl_arch_assign_cntr(d, evtid, rdtgrp->mon.rmid,
+ rdtgrp->mon.cntr_id[index],
+ rdtgrp->closid, 0);
+ if (!ret) {
+ clear_bit(rdtgrp->mon.cntr_id[index], d->mbm_cntr_map);
+ rdtgroup_free_cntr(r, rdtgrp, index);
+ }
+ }
+
+out_done:
+ return ret;
+}
Please merge this with almost identical rdtgroup_unassign_cntr()
+
+static int rdtgroup_str_to_mon_state(char *flag)
+{
+ int i, mon_state = 0;
+
+ 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;
It looks like this supports flags like "_lt", treating it as assigning
both local and total. I expect this should remove all flags instead?
+ default:
+ break;
+ }
+ }
+
+ return mon_state;
+}
hmmm ... so you removed assigning mon_state to ASSIGN_NONE from default,
but that did not change what this function returns since ASSIGN_NONE is 0
and mon_state is initialized to 0. Unknown flags should cause error so
that it is possible to add flags in the future. Above prevents us from
ever adding new flags.
+
+static struct rdtgroup *rdtgroup_find_grp(enum rdt_group_type rtype, char *p_grp, char *c_grp)
rdtgroup_find_grp() -> rdtgroup_find_grp_by_name()?
+{
+ 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(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);
Function should return error and exit here.
+
+ 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_update(rdtgrp, QOS_L3_MBM_TOTAL_EVENT_ID, d);
+ if (ret)
+ goto out_fail;
+ }
Should unassign occur before assign so that unassign can make counters available for
assign that follows?
+
+ if (assign_state & ASSIGN_LOCAL) {
+ ret = rdtgroup_assign_update(rdtgrp, QOS_L3_MBM_LOCAL_EVENT_ID, d);
+ if (ret)
+ goto out_fail;
+ }
+
+ if (unassign_state & ASSIGN_TOTAL) {
+ ret = rdtgroup_unassign_update(rdtgrp, QOS_L3_MBM_TOTAL_EVENT_ID, d);
+ if (ret)
+ goto out_fail;
+ }
+
+ if (unassign_state & ASSIGN_LOCAL) {
+ ret = rdtgroup_unassign_update(rdtgrp, QOS_L3_MBM_LOCAL_EVENT_ID, d);
+ if (ret)
+ goto out_fail;
+ }
+
+ goto next;
+
+out_fail:
+
+ return -EINVAL;
+}
+
+static ssize_t rdtgroup_mbm_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;
+ int ret;
+
+ if (!resctrl_arch_get_abmc_enabled())
+ return -EINVAL;
This needs to be protected by mutex.
+
+ /* 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);
+ rdt_last_cmd_clear();
+
+ while ((token = strsep(&buf, "\n")) != NULL) {
+ if (strstr(token, "//")) {
+ /*
+ * The CTRL_MON group processing:
+ * default CTRL_MON group: "//<flags>"
+ * non-default CTRL_MON group: "<CTRL_MON group>//flags"
+ * The CTRL_MON group will be empty string if it is a
+ * default group.
+ */
+ cmon_grp = strsep(&token, "//");
+
+ /*
+ * strsep returns empty string for contiguous delimiters.
+ * Make sure check for two consecutive delimiters and
+ * advance the token.
+ */
+ mon_grp = strsep(&token, "//");
+ if (*mon_grp != '\0') {
+ rdt_last_cmd_printf("Invalid CTRL_MON group format %s\n", token);
+ ret = -EINVAL;
+ break;
+ }
+
+ ret = rdtgroup_process_flags(r, RDTCTRL_GROUP, cmon_grp, mon_grp, token);
+ if (ret)
+ break;
+ } else if (strstr(token, "/")) {
+ /*
+ * MON group processing:
+ * MON_GROUP inside default CTRL_MON group: "/<MON group>/<flags>"
+ * MON_GROUP within CTRL_MON group: "<CTRL_MON group>/<MON group>/<flags>"
+ */
+ cmon_grp = strsep(&token, "/");
Isn't strsep(&token, "//") the same as strsep(&token, "/")? It looks like these two big branches
can be merged.
+
+ /* Extract the MON_GROUP. It cannot be empty string */
+ mon_grp = strsep(&token, "/");
+ if (*mon_grp == '\0') {
+ rdt_last_cmd_printf("Invalid MON_GROUP format %s\n", token);
+ ret = -EINVAL;
+ break;
+ }
+
+ ret = rdtgroup_process_flags(r, RDTMON_GROUP, cmon_grp, mon_grp, token);
+ if (ret)
+ break;
+ }
+ }
+
+ mutex_unlock(&rdtgroup_mutex);
+ cpus_read_unlock();
+
+ return ret ?: nbytes;
+}
+
#ifdef CONFIG_PROC_CPU_RESCTRL
/*
@@ -2277,9 +2589,10 @@ static struct rftype res_common_files[] = {
},
{
.name = "mbm_control",
- .mode = 0444,
+ .mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = rdtgroup_mbm_control_show,
+ .write = rdtgroup_mbm_control_write,
},
{
.name = "cpus_list",
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