There are now three meanings for "number of RMIDs":
1) The number for legacy features enumerated by CPUID leaf 0xF. This
is the maximum number of distinct values that can be loaded into the
IA32_PQR_ASSOC MSR. Note that systems with Sub-NUMA Cluster mode enabled
will force scaling down the CPUID enumerated value by the number of SNC
nodes per L3-cache.
2) The number of registers in MMIO space for each event. This
is enumerated in the XML files and is the value initialized into
event_group::num_rmids. This will be overwritten with a lower
value if hardware does not support all these registers at the
same time (see next case).
3) The number of "h/w counters" (this isn't a strictly accurate
description of how things work, but serves as a useful analogy that
does describe the limitations) feeding to those MMIO registers. This
is enumerated in telemetry_region::num_rmids returned from the call to
intel_pmt_get_regions_by_feature()
Event groups with insufficient "h/w counter" to track all RMIDs are
difficult for users to use, since the system may reassign "h/w counters"
at any time. This means that users cannot reliably collect two consecutive
event counts to compute the rate at which events are occurring.
Add a variable rdt_num_system_rmids which holds the number of RMIDs
supported by the system (including adjustments if Sub-NUMA Cluster
mode is enabled).
Use rdt_set_feature_disabled() to mark such under-resourced event groups
as unusable. Note that the rdt_options[] structure must now be writable
at run-time. The request to disable will be overridden if the user
explicitly requests to enable using the "rdt=" Linux boot argument.
Scan all enabled event groups and assign the RDT_RESOURCE_PERF_PKG
resource "num_rmids" value to the smallest of these values as this
value will be used later to compare against the number of RMIDs
supported by other resources.
N.B. Changed type of rdt_resource::num_rmid to u32 to match, and
print as unsigned value in rdt_num_rmids_show().
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
include/linux/resctrl.h | 2 +-
arch/x86/kernel/cpu/resctrl/internal.h | 4 +++
arch/x86/kernel/cpu/resctrl/core.c | 18 ++++++++++++-
arch/x86/kernel/cpu/resctrl/intel_aet.c | 36 +++++++++++++++++++++++++
arch/x86/kernel/cpu/resctrl/monitor.c | 2 ++
fs/resctrl/rdtgroup.c | 2 +-
6 files changed, 61 insertions(+), 3 deletions(-)
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index da76e9c37b69..74cd2979549b 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -288,7 +288,7 @@ struct rdt_resource {
int rid;
bool alloc_capable;
bool mon_capable;
- int num_rmid;
+ u32 num_rmid;
enum resctrl_scope ctrl_scope;
enum resctrl_scope mon_scope;
struct resctrl_cache cache;
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 83166dd0b9c8..a6c41068dc2f 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -18,6 +18,8 @@
#define RMID_VAL_UNAVAIL BIT_ULL(62)
+extern u32 rdt_num_system_rmids;
+
/*
* With the above fields in use 62 bits remain in MSR_IA32_QM_CTR for
* data to be returned. The counter width is discovered from the hardware
@@ -171,6 +173,8 @@ void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
bool rdt_is_feature_enabled(char *option);
+void rdt_set_feature_disabled(char *name);
+
#ifdef CONFIG_X86_RESCTRL_CPU_INTEL_AET
bool intel_aet_get_events(void);
void __exit intel_aet_exit(void);
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 83e046313600..31fb598482bf 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -807,7 +807,7 @@ struct rdt_options {
bool force_off, force_on;
};
-static struct rdt_options rdt_options[] __ro_after_init = {
+static struct rdt_options rdt_options[] = {
RDT_OPT(RDT_FLAG_CMT, "cmt", X86_FEATURE_CQM_OCCUP_LLC),
RDT_OPT(RDT_FLAG_MBM_TOTAL, "mbmtotal", X86_FEATURE_CQM_MBM_TOTAL),
RDT_OPT(RDT_FLAG_MBM_LOCAL, "mbmlocal", X86_FEATURE_CQM_MBM_LOCAL),
@@ -869,6 +869,22 @@ bool rdt_cpu_has(int flag)
return ret;
}
+/*
+ * Can be called during feature enumeration if sanity check of
+ * a features parameters indicates problems with the feature.
+ */
+void rdt_set_feature_disabled(char *name)
+{
+ struct rdt_options *o;
+
+ for (o = rdt_options; o < &rdt_options[NUM_RDT_OPTIONS]; o++) {
+ if (!strcmp(name, o->name)) {
+ o->force_off = true;
+ return;
+ }
+ }
+}
+
/*
* Hardware features that do not have X86_FEATURE_* bits.
* There is no "hardware does not support this at all" case.
diff --git a/arch/x86/kernel/cpu/resctrl/intel_aet.c b/arch/x86/kernel/cpu/resctrl/intel_aet.c
index e64a4630e95c..6958efbf7e81 100644
--- a/arch/x86/kernel/cpu/resctrl/intel_aet.c
+++ b/arch/x86/kernel/cpu/resctrl/intel_aet.c
@@ -15,6 +15,7 @@
#include <linux/cpu.h>
#include <linux/intel_vsec.h>
#include <linux/io.h>
+#include <linux/minmax.h>
#include <linux/resctrl.h>
#include <linux/slab.h>
@@ -56,6 +57,9 @@ struct pmt_event {
* @list: List of active event groups.
* @pkginfo: Per-package MMIO addresses of telemetry regions belonging to this group.
* @guid: Unique number per XML description file.
+ * @num_rmids: Number of RMIDS supported by this group. Adjusted downwards
+ * if enumeration from intel_pmt_get_regions_by_feature() indicates
+ * fewer RMIDs can be tracked simultaneously.
* @mmio_size: Number of bytes of MMIO registers for this group.
* @num_events: Number of events in this group.
* @evts: Array of event descriptors.
@@ -69,6 +73,7 @@ struct event_group {
/* Remaining fields initialized from XML file. */
u32 guid;
+ u32 num_rmids;
size_t mmio_size;
unsigned int num_events;
struct pmt_event evts[] __counted_by(num_events);
@@ -86,6 +91,7 @@ static LIST_HEAD(active_event_groups);
static struct event_group energy_0x26696143 = {
.name = "energy",
.guid = 0x26696143,
+ .num_rmids = 576,
.mmio_size = XML_MMIO_SIZE(576, 2, 3),
.num_events = 2,
.evts = {
@@ -101,6 +107,7 @@ static struct event_group energy_0x26696143 = {
static struct event_group perf_0x26557651 = {
.name = "perf",
.guid = 0x26557651,
+ .num_rmids = 576,
.mmio_size = XML_MMIO_SIZE(576, 7, 3),
.num_events = 7,
.evts = {
@@ -143,6 +150,22 @@ static bool skip_this_region(struct telemetry_region *tr, struct event_group *e)
return false;
}
+static bool check_rmid_count(struct event_group *e, struct pmt_feature_group *p)
+{
+ struct telemetry_region *tr;
+
+ for (int i = 0; i < p->count; i++) {
+ tr = &p->regions[i];
+ if (skip_this_region(tr, e))
+ continue;
+
+ if (tr->num_rmids < rdt_num_system_rmids)
+ return false;
+ }
+
+ return true;
+}
+
static void free_pkg_mmio_info(struct pkg_mmio_info **mmi)
{
int num_pkgs = topology_max_packages();
@@ -165,12 +188,18 @@ DEFINE_FREE(pkg_mmio_info, struct pkg_mmio_info **, free_pkg_mmio_info(_T))
*/
static int discover_events(struct event_group *e, struct pmt_feature_group *p)
{
+ struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_PERF_PKG].r_resctrl;
struct pkg_mmio_info **pkginfo __free(pkg_mmio_info) = NULL;
int *pkgcounts __free(kfree) = NULL;
struct telemetry_region *tr;
struct pkg_mmio_info *mmi;
int num_pkgs;
+ /* Potentially disable feature if insufficient RMIDs */
+ if (!check_rmid_count(e, p))
+ rdt_set_feature_disabled(e->name);
+
+ /* User can override above disable from kernel command line */
if (!rdt_is_feature_enabled(e->name))
return -EINVAL;
@@ -182,6 +211,8 @@ static int discover_events(struct event_group *e, struct pmt_feature_group *p)
if (skip_this_region(tr, e))
continue;
+ e->num_rmids = min(e->num_rmids, tr->num_rmids);
+
if (!pkgcounts) {
pkgcounts = kcalloc(num_pkgs, sizeof(*pkgcounts), GFP_KERNEL);
if (!pkgcounts)
@@ -228,6 +259,11 @@ static int discover_events(struct event_group *e, struct pmt_feature_group *p)
resctrl_enable_mon_event(eventid, true, e->evts[i].bin_bits, &e->evts[i]);
}
+ if (r->num_rmid)
+ r->num_rmid = min(r->num_rmid, e->num_rmids);
+ else
+ r->num_rmid = e->num_rmids;
+
return 0;
}
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 51d7d99336c6..aac7b7310d81 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -33,6 +33,7 @@ bool rdt_mon_capable;
#define CF(cf) ((unsigned long)(1048576 * (cf) + 0.5))
+u32 rdt_num_system_rmids;
static int snc_nodes_per_l3_cache = 1;
/*
@@ -358,6 +359,7 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
resctrl_rmid_realloc_limit = boot_cpu_data.x86_cache_size * 1024;
hw_res->mon_scale = boot_cpu_data.x86_cache_occ_scale / snc_nodes_per_l3_cache;
r->num_rmid = (boot_cpu_data.x86_cache_max_rmid + 1) / snc_nodes_per_l3_cache;
+ rdt_num_system_rmids = r->num_rmid;
hw_res->mbm_width = MBM_CNTR_WIDTH_BASE;
if (mbm_offset > 0 && mbm_offset <= MBM_CNTR_WIDTH_OFFSET_MAX)
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 11792e841525..9e4df213906f 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1135,7 +1135,7 @@ static int rdt_num_rmids_show(struct kernfs_open_file *of,
{
struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
- seq_printf(seq, "%d\n", r->num_rmid);
+ seq_printf(seq, "%u\n", r->num_rmid);
return 0;
}
--
2.50.0