Commit d0891647 authored by Tony Luck's avatar Tony Luck Committed by Borislav Petkov (AMD)
Browse files

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 needs 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: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
parent 0ecc988b

fs/resctrl/internal.h

+4 −0
Original line number Diff line number Diff line
@@ -369,6 +369,10 @@ 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);

fs/resctrl/monitor.c

+25 −29
Original line number Diff line number Diff line
@@ -903,20 +903,29 @@ 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_limit;

	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(). Note that the limbo handler continues to

	 * access rmid_ptrs[] after resctrl is unmounted.

	 */

	if (rmid_ptrs)

		return 0;



	idx_limit = resctrl_arch_system_num_rmid_idx();

	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];
@@ -929,30 +938,24 @@ 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);

}
@@ -1830,7 +1833,8 @@ 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
@@ -1850,12 +1854,6 @@ 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",
@@ -1902,6 +1900,4 @@ void resctrl_l3_mon_resource_exit(void) 
		return;



	closid_num_dirty_rmid_free();



	dom_data_exit(r);

}

fs/resctrl/rdtgroup.c

+5 −0
Original line number Diff line number Diff line
@@ -2800,6 +2800,10 @@ 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;
@@ -4655,4 +4659,5 @@ void resctrl_exit(void) 
	 */



	resctrl_l3_mon_resource_exit();

	free_rmid_lru_list();

}