[RFC PATCH v3 08/17] x86/resctrl: Initialize assignable counters bitmap

Babu Moger
2024-03-29T01:08:35Z

AMD Hardware provides a set of counters when the ABMC feature is supported.
These counters are used for assigning events to the resctrl group.

Introduce the bitmap assign_cntrs_free_map to allocate and free the
counters.

Signed-off-by: Babu Moger <babu.moger@amd.com>

---
v3: Changed the bitmap name to assign_cntrs_free_map. Removed abmc
from the name.

v2: Changed the bitmap name to assignable_counter_free_map from
abmc_counter_free_map.
---
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index f49073c86884..2c7583e7b541 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -186,6 +186,22 @@ bool closid_allocated(unsigned int closid)
return !test_bit(closid, &closid_free_map);
}

+static u64 assign_cntrs_free_map;
+static u32 assign_cntrs_free_map_len;
+
+static void assign_cntrs_init(void)
+{
+ struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+
+ if (r->mbm_assign_cntrs > 64) {
+ r->mbm_assign_cntrs = 64;
+ WARN(1, "Cannot support more than 64 Assignable counters\n");
+ }
+
+ assign_cntrs_free_map = BIT_MASK(r->mbm_assign_cntrs) - 1;
+ assign_cntrs_free_map_len = r->mbm_assign_cntrs;
+}
+
/**
* rdtgroup_mode_by_closid - Return mode of resource group with closid
* @closid: closid if the resource group
@@ -2459,6 +2475,9 @@ static int resctrl_abmc_setup(enum resctrl_res_level l, bool enable)
struct rdt_resource *r = &rdt_resources_all[l].r_resctrl;
struct rdt_domain *d;

+ /* Reset the counters bitmap */
+ assign_cntrs_init();
+
/* Update QOS_CFG MSR on all the CPUs in cpu_mask */
list_for_each_entry(d, &r->domains, list) {
on_each_cpu_mask(&d->cpu_mask, resctrl_abmc_msrwrite, &enable, 1);
--
2.34.1