Hardware provides a set of counters when mbm_cntr_assignable feature is
supported. These counters are used for assigning the events in resctrl
a group when the feature is enabled. The kernel must manage and track the
number of available counters.
Introduce mbm_cntr_free_map bitmap to track available counters and set
of routines to allocate and free the counters.
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v7: Removed the static allocation and now allocating bitmap mbm_cntr_free_map
dynamically.
Passed the struct rdt_resource mbm_cntr_alloc and mbm_cntr_free.
Removed the reference of ABMC and changed it mbm_cntr_assign.
Few other text changes.
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/core.c | 2 +-
arch/x86/kernel/cpu/resctrl/internal.h | 4 +++-
arch/x86/kernel/cpu/resctrl/monitor.c | 31 +++++++++++++++++++++++++-
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 19 ++++++++++++++++
include/linux/resctrl.h | 2 ++
5 files changed, 55 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 49d147e2e4e5..00ad00258df2 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -1140,7 +1140,7 @@ static void __exit resctrl_exit(void)
rdtgroup_exit();
if (r->mon_capable)
- rdt_put_mon_l3_config();
+ rdt_put_mon_l3_config(r);
}
__exitcall(resctrl_exit);
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index a45ae410274c..99f9103a35ba 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -633,7 +633,7 @@ void closid_free(int closid);
int alloc_rmid(u32 closid);
void free_rmid(u32 closid, u32 rmid);
int rdt_get_mon_l3_config(struct rdt_resource *r);
-void __exit rdt_put_mon_l3_config(void);
+void __exit rdt_put_mon_l3_config(struct rdt_resource *r);
bool __init rdt_cpu_has(int flag);
void mon_event_count(void *info);
int rdtgroup_mondata_show(struct seq_file *m, void *arg);
@@ -654,6 +654,8 @@ 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(struct rdt_resource *r, 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/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index e3e71843401a..f98cc5b9bebc 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -1175,6 +1175,30 @@ static __init int snc_get_config(void)
return ret;
}
+/*
+ * Counter bitmap for tracking the available counters.
+ * 'mbm_cntr_assign' mode provides set of hardware counters for assigning
+ * RMID, event pair. Each RMID and event pair takes one hardware counter.
+ * Kernel needs to keep track of the number of available counters.
+ */
+static int mbm_cntrs_init(struct rdt_resource *r)
+{
+ if (r->mon.mbm_cntr_assignable) {
+ r->mon.mbm_cntr_free_map = bitmap_zalloc(r->mon.num_mbm_cntrs,
+ GFP_KERNEL);
+ if (!r->mon.mbm_cntr_free_map)
+ return -ENOMEM;
+ bitmap_fill(r->mon.mbm_cntr_free_map, r->mon.num_mbm_cntrs);
+ }
+ return 0;
+}
+
+static void __exit mbm_cntrs_exit(struct rdt_resource *r)
+{
+ if (r->mon.mbm_cntr_assignable)
+ bitmap_free(r->mon.mbm_cntr_free_map);
+}
+
int __init rdt_get_mon_l3_config(struct rdt_resource *r)
{
unsigned int mbm_offset = boot_cpu_data.x86_cache_mbm_width_offset;
@@ -1240,6 +1264,10 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
}
}
+ ret = mbm_cntrs_init(r);
+ if (ret)
+ return ret;
+
l3_mon_evt_init(r);
r->mon_capable = true;
@@ -1247,9 +1275,10 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
return 0;
}
-void __exit rdt_put_mon_l3_config(void)
+void __exit rdt_put_mon_l3_config(struct rdt_resource *r)
{
dom_data_exit();
+ mbm_cntrs_exit(r);
}
void __init intel_rdt_mbm_apply_quirk(void)
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index ba737890d5c2..a51992984832 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -185,6 +185,25 @@ bool closid_allocated(unsigned int closid)
return !test_bit(closid, &closid_free_map);
}
+int mbm_cntr_alloc(struct rdt_resource *r)
+{
+ int cntr_id;
+
+ cntr_id = find_first_bit(r->mon.mbm_cntr_free_map,
+ r->mon.num_mbm_cntrs);
+ if (cntr_id >= r->mon.num_mbm_cntrs)
+ return -ENOSPC;
+
+ __clear_bit(cntr_id, r->mon.mbm_cntr_free_map);
+
+ return cntr_id;
+}
+
+void mbm_cntr_free(struct rdt_resource *r, u32 cntr_id)
+{
+ __set_bit(cntr_id, r->mon.mbm_cntr_free_map);
+}
+
/**
* rdtgroup_mode_by_closid - Return mode of resource group with closid
* @closid: closid if the resource group
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index f11d6fdfd977..aab22ff8e0c1 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -187,12 +187,14 @@ enum resctrl_scope {
* @num_rmid: Number of RMIDs available
* @num_mbm_cntrs: Number of assignable monitoring counters
* @mbm_cntr_assignable:Is system capable of supporting monitor assignment?
+ * @mbm_cntr_free_map: bitmap of number of assignable MBM counters
* @evt_list: List of monitoring events
*/
struct resctrl_mon {
int num_rmid;
int num_mbm_cntrs;
bool mbm_cntr_assignable;
+ unsigned long *mbm_cntr_free_map;
struct list_head evt_list;
};
--
2.34.1
