Commit 36bbc5b4 authored by Sudeep Holla's avatar Sudeep Holla
Browse files

cacheinfo: Allow early detection and population of cache attributes 

Some architecture/platforms may need to setup cache properties very
early in the boot along with other cpu topologies so that all these
information can be used to build sched_domains which is used by the
scheduler.

Allow detect_cache_attributes to be called quite early during the boot.

Link: https://lore.kernel.org/r/20220704101605.1318280-7-sudeep.holla@arm.com


Tested-by: default avatarIonela Voinescu <ionela.voinescu@arm.com>
Tested-by: default avatarConor Dooley <conor.dooley@microchip.com>
Reviewed-by: default avatarGavin Shan <gshan@redhat.com>
Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent cc1cfc47

drivers/base/cacheinfo.c

+37 −18
Original line number Diff line number Diff line
@@ -193,14 +193,8 @@ static int cache_setup_of_node(unsigned int cpu) 
{

	struct device_node *np;

	struct cacheinfo *this_leaf;

	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

	unsigned int index = 0;



	/* skip if fw_token is already populated */

	if (this_cpu_ci->info_list->fw_token) {

		return 0;

	}



	np = of_cpu_device_node_get(cpu);

	if (!np) {

		pr_err("Failed to find cpu%d device node\n", cpu);
@@ -236,6 +230,18 @@ int __weak cache_setup_acpi(unsigned int cpu) 


unsigned int coherency_max_size;



static int cache_setup_properties(unsigned int cpu)

{

	int ret = 0;



	if (of_have_populated_dt())

		ret = cache_setup_of_node(cpu);

	else if (!acpi_disabled)

		ret = cache_setup_acpi(cpu);



	return ret;

}



static int cache_shared_cpu_map_setup(unsigned int cpu)

{

	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
@@ -246,21 +252,21 @@ static int cache_shared_cpu_map_setup(unsigned int cpu) 
	if (this_cpu_ci->cpu_map_populated)

		return 0;



	if (of_have_populated_dt())

		ret = cache_setup_of_node(cpu);

	else if (!acpi_disabled)

		ret = cache_setup_acpi(cpu);



	/*

	 * skip setting up cache properties if LLC is valid, just need

	 * to update the shared cpu_map if the cache attributes were

	 * populated early before all the cpus are brought online

	 */

	if (!last_level_cache_is_valid(cpu)) {

		ret = cache_setup_properties(cpu);

		if (ret)

			return ret;

	}



	for (index = 0; index < cache_leaves(cpu); index++) {

		unsigned int i;



		this_leaf = per_cpu_cacheinfo_idx(cpu, index);

		/* skip if shared_cpu_map is already populated */

		if (!cpumask_empty(&this_leaf->shared_cpu_map))

			continue;



		cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);

		for_each_online_cpu(i) {
@@ -330,17 +336,28 @@ int __weak populate_cache_leaves(unsigned int cpu) 
	return -ENOENT;

}



static int detect_cache_attributes(unsigned int cpu)

int detect_cache_attributes(unsigned int cpu)

{

	int ret;



	/* Since early detection of the cacheinfo is allowed via this

	 * function and this also gets called as CPU hotplug callbacks via

	 * cacheinfo_cpu_online, the initialisation can be skipped and only

	 * CPU maps can be updated as the CPU online status would be update

	 * if called via cacheinfo_cpu_online path.

	 */

	if (per_cpu_cacheinfo(cpu))

		goto update_cpu_map;



	if (init_cache_level(cpu) || !cache_leaves(cpu))

		return -ENOENT;



	per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),

					 sizeof(struct cacheinfo), GFP_KERNEL);

	if (per_cpu_cacheinfo(cpu) == NULL)

	if (per_cpu_cacheinfo(cpu) == NULL) {

		cache_leaves(cpu) = 0;

		return -ENOMEM;

	}



	/*

	 * populate_cache_leaves() may completely setup the cache leaves and
@@ -349,6 +366,8 @@ static int detect_cache_attributes(unsigned int cpu) 
	ret = populate_cache_leaves(cpu);

	if (ret)

		goto free_ci;



update_cpu_map:

	/*

	 * For systems using DT for cache hierarchy, fw_token

	 * and shared_cpu_map will be set up here only if they are

include/linux/cacheinfo.h

+1 −0
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ int populate_cache_leaves(unsigned int cpu); 
int cache_setup_acpi(unsigned int cpu);

bool last_level_cache_is_valid(unsigned int cpu);

bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y);

int detect_cache_attributes(unsigned int cpu);

#ifndef CONFIG_ACPI_PPTT

/*

 * acpi_find_last_cache_level is only called on ACPI enabled