[RFC PATCH 11/17] x86/resctrl: Allocate per-package structures for known events

From: Tony Luck
Date: Mon Mar 03 2025 - 18:36:50 EST


Use the per-package counts of known events to allocate arrays to
make a copy of just the known events.

Add hook into resctrl_exit() to cleanup.

Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
---
arch/x86/kernel/cpu/resctrl/internal.h | 2 +
arch/x86/kernel/cpu/resctrl/core.c | 2 +
arch/x86/kernel/cpu/resctrl/intel_pmt.c | 59 ++++++++++++++++++++++++-
3 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 65bbe223f8a1..24c4ab331c3c 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -641,11 +641,13 @@ int rdt_get_mon_l3_config(struct rdt_resource *r);
int rdt_get_intel_pmt_mon_config(void);
void rdt_get_intel_pmt_mount(void);
void setup_intel_pmt_mon_domain(int cpu, int id, struct rdt_resource *r, struct list_head *add_pos);
+void rdt_intel_pmt_exit(void);
#else
static inline int rdt_get_intel_pmt_mon_config(void) { return 0; }
static inline void rdt_get_intel_pmt_mount(void) { }
static inline void setup_intel_pmt_mon_domain(int cpu, int id, struct rdt_resource *r,
struct list_head *add_pos) { }
+static inline void rdt_intel_pmt_exit(void) { };
#endif
void __exit rdt_put_mon_l3_config(void);
bool __init rdt_cpu_has(int flag);
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index b6e6a25520f7..da44d00acd98 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -1170,6 +1170,8 @@ static void __exit resctrl_exit(void)

cpuhp_remove_state(rdt_online);

+ rdt_intel_pmt_exit();
+
rdtgroup_exit();

if (r->mon_capable)
diff --git a/arch/x86/kernel/cpu/resctrl/intel_pmt.c b/arch/x86/kernel/cpu/resctrl/intel_pmt.c
index 78ab6d899ee2..754748d858c6 100644
--- a/arch/x86/kernel/cpu/resctrl/intel_pmt.c
+++ b/arch/x86/kernel/cpu/resctrl/intel_pmt.c
@@ -147,6 +147,26 @@ static bool count_events(struct pkg_info *pkg, int max_pkgs, struct pmt_feature_
return found;
}

+static int setup(struct pkg_info *pkg, int pkgnum, struct pmt_feature_group *p, int slot)
+{
+ struct telem_entry **tentry;
+
+ for (int i = 0; i < p->count; i++) {
+ for (tentry = telem_entry; *tentry; tentry++) {
+ if (!(*tentry)->active)
+ continue;
+ if (pkgnum != p->regions[i].plat_info.package_id)
+ continue;
+ if (p->regions[i].guid != (*tentry)->guid)
+ continue;
+
+ pkg[pkgnum].regions[slot++] = p->regions[i];
+ }
+ }
+
+ return slot;
+}
+
DEFINE_FREE(intel_pmt_put_feature_group, struct pmt_feature_group *, \
if (!IS_ERR_OR_NULL(_T)) \
intel_pmt_put_feature_group(_T))
@@ -157,6 +177,8 @@ static bool get_events(void)
struct pmt_feature_group *p2 __free(intel_pmt_put_feature_group) = NULL;
int num_pkgs = topology_max_packages();
struct pkg_info *pkg __free(kfree) = NULL;
+ bool found_known_features = false;
+ int i, slot;

pkg = kmalloc_array(num_pkgs, sizeof(*pkg_info), GFP_KERNEL | __GFP_ZERO);
if (!pkg)
@@ -175,13 +197,32 @@ static bool get_events(void)
if (!count_events(pkg, num_pkgs, p2))
intel_pmt_put_feature_group(no_free_ptr(p2));

+ for (i = 0; i < num_pkgs; i++) {
+ if (!pkg[i].count)
+ continue;
+ found_known_features = true;
+ pkg[i].regions = kmalloc_array(pkg[i].count, sizeof(*pkg[i].regions), GFP_KERNEL);
+ if (!pkg[i].regions)
+ goto fail;
+
+ slot = 0;
+ if (!IS_ERR_VALUE(p1))
+ slot = setup(pkg, i, p1, slot);
+ if (!IS_ERR_VALUE(p2))
+ slot = setup(pkg, i, p2, slot);
+ }
+
if (!IS_ERR_OR_NULL(p1))
feat_energy = no_free_ptr(p1);
if (!IS_ERR_OR_NULL(p2))
feat_perf = no_free_ptr(p2);
pkg_info = no_free_ptr(pkg);

- return true;
+ return found_known_features;
+fail:
+ while (--i > 0)
+ kfree(pkg[i].regions);
+ return false;
}

int rdt_get_intel_pmt_mon_config(void)
@@ -193,6 +234,22 @@ int rdt_get_intel_pmt_mon_config(void)
return 1;
}

+void rdt_intel_pmt_exit(void)
+{
+ int num_pkgs = topology_max_packages();
+
+ if (pkg_info) {
+ for (int i = 0; i < num_pkgs; i++)
+ kfree(pkg_info[i].regions);
+ kfree(pkg_info);
+ }
+
+ if (feat_energy)
+ intel_pmt_put_feature_group(feat_energy);
+ if (feat_perf)
+ intel_pmt_put_feature_group(feat_perf);
+}
+
void rdt_get_intel_pmt_mount(void)
{
struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_INTEL_PMT].r_resctrl;
--
2.48.1