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Message-ID: <20250912221053.11349-25-tony.luck@intel.com>
Date: Fri, 12 Sep 2025 15:10:45 -0700
From: Tony Luck <tony.luck@...el.com>
To: Fenghua Yu <fenghuay@...dia.com>,
Reinette Chatre <reinette.chatre@...el.com>,
Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>,
Peter Newman <peternewman@...gle.com>,
James Morse <james.morse@....com>,
Babu Moger <babu.moger@....com>,
Drew Fustini <dfustini@...libre.com>,
Dave Martin <Dave.Martin@....com>,
Chen Yu <yu.c.chen@...el.com>
Cc: x86@...nel.org,
linux-kernel@...r.kernel.org,
patches@...ts.linux.dev,
Tony Luck <tony.luck@...el.com>
Subject: [PATCH v10 24/28] fs/resctrl: Move RMID initialization to first mount
L3 monitor features are enumerated during resctrl initialization
and rmid_ptrs[] that tracks all RMIDs and depends on the
number of supported RMIDs is allocated during this time.
Telemetry monitor features are enumerated during first resctrl mount and
may support a different number of RMIDs compared to L3 monitor features.
Delay allocation and initialization of rmid_ptrs[] until first mount.
Since the number of RMIDs cannot change on later mounts, keep the same
set of rmid_ptrs[] until resctrl_exit(). This is required because the
limbo handler keeps running after resctrl is unmounted and may likely
need to access rmid_ptrs[] as it keeps tracking busy RMIDs after unmount.
Rename routines to match what they now do:
dom_data_init() -> setup_rmid_lru_list()
dom_data_exit() -> free_rmid_lru_list()
Signed-off-by: Tony Luck <tony.luck@...el.com>
---
fs/resctrl/internal.h | 4 ++++
fs/resctrl/monitor.c | 50 +++++++++++++++++++------------------------
fs/resctrl/rdtgroup.c | 5 +++++
3 files changed, 31 insertions(+), 28 deletions(-)
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index ec6f01751424..f2296f1efc12 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -367,6 +367,10 @@ int closids_supported(void);
void closid_free(int closid);
+int setup_rmid_lru_list(void);
+
+void free_rmid_lru_list(void);
+
int alloc_rmid(u32 closid);
void free_rmid(u32 closid, u32 rmid);
diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index 8f15bdf40593..f85bd6a401c1 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -882,20 +882,27 @@ void mbm_setup_overflow_handler(struct rdt_l3_mon_domain *dom, unsigned long del
schedule_delayed_work_on(cpu, &dom->mbm_over, delay);
}
-static int dom_data_init(struct rdt_resource *r)
+int setup_rmid_lru_list(void)
{
u32 idx_limit = resctrl_arch_system_num_rmid_idx();
struct rmid_entry *entry = NULL;
- int err = 0, i;
u32 idx;
+ int i;
- mutex_lock(&rdtgroup_mutex);
+ if (!resctrl_arch_mon_capable())
+ return 0;
+
+ /*
+ * Called on every mount, but the number of RMIDs cannot change
+ * after the first mount, so keep using the same set of rmid_ptrs[]
+ * until resctrl_exit().
+ */
+ if (rmid_ptrs)
+ return 0;
rmid_ptrs = kcalloc(idx_limit, sizeof(struct rmid_entry), GFP_KERNEL);
- if (!rmid_ptrs) {
- err = -ENOMEM;
- goto out_unlock;
- }
+ if (!rmid_ptrs)
+ return -ENOMEM;
for (i = 0; i < idx_limit; i++) {
entry = &rmid_ptrs[i];
@@ -908,30 +915,24 @@ static int dom_data_init(struct rdt_resource *r)
/*
* RESCTRL_RESERVED_CLOSID and RESCTRL_RESERVED_RMID are special and
* are always allocated. These are used for the rdtgroup_default
- * control group, which will be setup later in resctrl_init().
+ * control group, which was setup earlier in rdtgroup_setup_default().
*/
idx = resctrl_arch_rmid_idx_encode(RESCTRL_RESERVED_CLOSID,
RESCTRL_RESERVED_RMID);
entry = __rmid_entry(idx);
list_del(&entry->list);
-out_unlock:
- mutex_unlock(&rdtgroup_mutex);
-
- return err;
+ return 0;
}
-static void dom_data_exit(struct rdt_resource *r)
+void free_rmid_lru_list(void)
{
- mutex_lock(&rdtgroup_mutex);
-
- if (!r->mon_capable)
- goto out_unlock;
+ if (!resctrl_arch_mon_capable())
+ return;
+ mutex_lock(&rdtgroup_mutex);
kfree(rmid_ptrs);
rmid_ptrs = NULL;
-
-out_unlock:
mutex_unlock(&rdtgroup_mutex);
}
@@ -1805,7 +1806,8 @@ static void closid_num_dirty_rmid_free(void)
* resctrl_l3_mon_resource_init() - Initialise global monitoring structures.
*
* Allocate and initialise global monitor resources that do not belong to a
- * specific domain. i.e. the rmid_ptrs[] used for the limbo and free lists.
+ * specific domain. i.e. the closid_num_dirty_rmid[] used to find the CLOSID
+ * with the cleanest set of RMIDs.
* Called once during boot after the struct rdt_resource's have been configured
* but before the filesystem is mounted.
* Resctrl's cpuhp callbacks may be called before this point to bring a domain
@@ -1825,12 +1827,6 @@ int resctrl_l3_mon_resource_init(void)
if (ret)
return ret;
- ret = dom_data_init(r);
- if (ret) {
- closid_num_dirty_rmid_free();
- return ret;
- }
-
if (resctrl_arch_is_evt_configurable(QOS_L3_MBM_TOTAL_EVENT_ID)) {
mon_event_all[QOS_L3_MBM_TOTAL_EVENT_ID].configurable = true;
resctrl_file_fflags_init("mbm_total_bytes_config",
@@ -1879,6 +1875,4 @@ void resctrl_l3_mon_resource_exit(void)
return;
closid_num_dirty_rmid_free();
-
- dom_data_exit(r);
}
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 19f0feb51420..94fa7fb7d598 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -2734,6 +2734,10 @@ static int rdt_get_tree(struct fs_context *fc)
goto out;
}
+ ret = setup_rmid_lru_list();
+ if (ret)
+ goto out;
+
ret = rdtgroup_setup_root(ctx);
if (ret)
goto out;
@@ -4570,4 +4574,5 @@ void resctrl_exit(void)
*/
resctrl_l3_mon_resource_exit();
+ free_rmid_lru_list();
}
--
2.51.0
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