Hardware provides a set of counters when mbm_cntr_assignable feature is
supported. These counters are used for assigning the events in resctrl
group when the feature is enabled.
Introduce mbm_cntrs_free_map bitmap to track available and free counters
and set of routines to allocate and free the counters.
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v6: Removed the variable mbm_cntrs_free_map_len. This is not required.
Removed the call mbm_cntrs_init() in arch code. This needs to be
done at higher level.
Used DECLARE_BITMAP to initialize mbm_cntrs_free_map.
Moved all the counter interfaces mbm_cntr_alloc() and mbm_cntr_free()
in here as part of separating arch and fs bits.
v5:
Updated the comments and commit log.
Few renames
num_cntrs_free_map -> mbm_cntrs_free_map
num_cntrs_init -> mbm_cntrs_init
Added initialization in rdt_get_tree because the default ABMC
enablement happens during the init.
v4: Changed the name to num_cntrs where applicable.
Used bitmap apis.
Added more comments for the globals.
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/internal.h | 2 ++
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 33 ++++++++++++++++++++++++++
2 files changed, 35 insertions(+)
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 154983a67646..6263362496a3 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -662,6 +662,8 @@ void __check_limbo(struct rdt_mon_domain *d, bool force_free);
void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
void __init resctrl_file_fflags_init(const char *config,
unsigned long fflags);
+int mbm_cntr_alloc(struct rdt_resource *r);
+void mbm_cntr_free(u32 cntr_id);
void rdt_staged_configs_clear(void);
bool closid_allocated(unsigned int closid);
int resctrl_find_cleanest_closid(void);
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index ab4fab3b7cf1..c818965e36c9 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -185,6 +185,37 @@ bool closid_allocated(unsigned int closid)
return !test_bit(closid, &closid_free_map);
}
+/*
+ * Counter bitmap for tracking the available counters.
+ * ABMC feature provides set of hardware counters for enabling events.
+ * Each event takes one hardware counter. Kernel needs to keep track
+ * of number of available counters.
+ */
+static DECLARE_BITMAP(mbm_cntrs_free_map, 64);
+
+static void mbm_cntrs_init(struct rdt_resource *r)
+{
+ bitmap_fill(mbm_cntrs_free_map, r->mon.num_mbm_cntrs);
+}
+
+int mbm_cntr_alloc(struct rdt_resource *r)
+{
+ int cntr_id;
+
+ cntr_id = find_first_bit(mbm_cntrs_free_map, r->mon.num_mbm_cntrs);
+ if (cntr_id >= r->mon.num_mbm_cntrs)
+ return -ENOSPC;
+
+ __clear_bit(cntr_id, mbm_cntrs_free_map);
+
+ return cntr_id;
+}
+
+void mbm_cntr_free(u32 cntr_id)
+{
+ __set_bit(cntr_id, mbm_cntrs_free_map);
+}
+
/**
* rdtgroup_mode_by_closid - Return mode of resource group with closid
* @closid: closid if the resource group
@@ -2748,6 +2779,8 @@ static int rdt_get_tree(struct fs_context *fc)
closid_init();
+ mbm_cntrs_init(&rdt_resources_all[RDT_RESOURCE_L3].r_resctrl);
+
if (resctrl_arch_mon_capable())
flags |= RFTYPE_MON;
--
2.34.1
