diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers b/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers new file mode 100644 index 000000000000..45985e411f13 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers @@ -0,0 +1,25 @@ +What: /sys/devices/virtual/memory_tiering/ +Date: August 2022 +Contact: Linux memory management mailing list +Description: A collection of all the memory tiers allocated. + + Individual memory tier details are contained in subdirectories + named by the abstract distance of the memory tier. + + /sys/devices/virtual/memory_tiering/memory_tierN/ + + +What: /sys/devices/virtual/memory_tiering/memory_tierN/ + /sys/devices/virtual/memory_tiering/memory_tierN/nodes +Date: August 2022 +Contact: Linux memory management mailing list +Description: Directory with details of a specific memory tier + + This is the directory containing information about a particular + memory tier, memtierN, where N is derived based on abstract distance. + + A smaller value of N implies a higher (faster) memory tier in the + hierarchy. + + nodes: NUMA nodes that are part of this memory tier. + diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index c82eb0111383..f116b7b6333e 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -19,6 +19,7 @@ struct memory_tier { * adistance_start .. adistance_start + MEMTIER_CHUNK_SIZE */ int adistance_start; + struct device dev; /* All the nodes that are part of all the lower memory tiers. */ nodemask_t lower_tier_mask; }; @@ -36,6 +37,12 @@ static DEFINE_MUTEX(memory_tier_lock); static LIST_HEAD(memory_tiers); static struct node_memory_type_map node_memory_types[MAX_NUMNODES]; static struct memory_dev_type *default_dram_type; + +static struct bus_type memory_tier_subsys = { + .name = "memory_tiering", + .dev_name = "memory_tier", +}; + #ifdef CONFIG_MIGRATION static int top_tier_adistance; /* @@ -98,8 +105,63 @@ static int top_tier_adistance; static struct demotion_nodes *node_demotion __read_mostly; #endif /* CONFIG_MIGRATION */ +static inline struct memory_tier *to_memory_tier(struct device *device) +{ + return container_of(device, struct memory_tier, dev); +} + +static __always_inline nodemask_t get_memtier_nodemask(struct memory_tier *memtier) +{ + nodemask_t nodes = NODE_MASK_NONE; + struct memory_dev_type *memtype; + + list_for_each_entry(memtype, &memtier->memory_types, tier_sibiling) + nodes_or(nodes, nodes, memtype->nodes); + + return nodes; +} + +static void memory_tier_device_release(struct device *dev) +{ + struct memory_tier *tier = to_memory_tier(dev); + /* + * synchronize_rcu in clear_node_memory_tier makes sure + * we don't have rcu access to this memory tier. + */ + kfree(tier); +} + +static ssize_t nodes_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int ret; + nodemask_t nmask; + + mutex_lock(&memory_tier_lock); + nmask = get_memtier_nodemask(to_memory_tier(dev)); + ret = sysfs_emit(buf, "%*pbl\n", nodemask_pr_args(&nmask)); + mutex_unlock(&memory_tier_lock); + return ret; +} +static DEVICE_ATTR_RO(nodes); + +static struct attribute *memtier_dev_attrs[] = { + &dev_attr_nodes.attr, + NULL +}; + +static const struct attribute_group memtier_dev_group = { + .attrs = memtier_dev_attrs, +}; + +static const struct attribute_group *memtier_dev_groups[] = { + &memtier_dev_group, + NULL +}; + static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype) { + int ret; bool found_slot = false; struct memory_tier *memtier, *new_memtier; int adistance = memtype->adistance; @@ -123,15 +185,14 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty list_for_each_entry(memtier, &memory_tiers, list) { if (adistance == memtier->adistance_start) { - list_add(&memtype->tier_sibiling, &memtier->memory_types); - return memtier; + goto link_memtype; } else if (adistance < memtier->adistance_start) { found_slot = true; break; } } - new_memtier = kmalloc(sizeof(struct memory_tier), GFP_KERNEL); + new_memtier = kzalloc(sizeof(struct memory_tier), GFP_KERNEL); if (!new_memtier) return ERR_PTR(-ENOMEM); @@ -142,8 +203,23 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty list_add_tail(&new_memtier->list, &memtier->list); else list_add_tail(&new_memtier->list, &memory_tiers); - list_add(&memtype->tier_sibiling, &new_memtier->memory_types); - return new_memtier; + + new_memtier->dev.id = adistance >> MEMTIER_CHUNK_BITS; + new_memtier->dev.bus = &memory_tier_subsys; + new_memtier->dev.release = memory_tier_device_release; + new_memtier->dev.groups = memtier_dev_groups; + + ret = device_register(&new_memtier->dev); + if (ret) { + list_del(&memtier->list); + put_device(&memtier->dev); + return ERR_PTR(ret); + } + memtier = new_memtier; + +link_memtype: + list_add(&memtype->tier_sibiling, &memtier->memory_types); + return memtier; } static struct memory_tier *__node_get_memory_tier(int node) @@ -275,17 +351,6 @@ static void disable_all_demotion_targets(void) synchronize_rcu(); } -static __always_inline nodemask_t get_memtier_nodemask(struct memory_tier *memtier) -{ - nodemask_t nodes = NODE_MASK_NONE; - struct memory_dev_type *memtype; - - list_for_each_entry(memtype, &memtier->memory_types, tier_sibiling) - nodes_or(nodes, nodes, memtype->nodes); - - return nodes; -} - /* * Find an automatic demotion target for all memory * nodes. Failing here is OK. It might just indicate @@ -433,11 +498,7 @@ static struct memory_tier *set_node_memory_tier(int node) static void destroy_memory_tier(struct memory_tier *memtier) { list_del(&memtier->list); - /* - * synchronize_rcu in clear_node_memory_tier makes sure - * we don't have rcu access to this memory tier. - */ - kfree(memtier); + device_unregister(&memtier->dev); } static bool clear_node_memory_tier(int node) @@ -566,9 +627,13 @@ static int __meminit memtier_hotplug_callback(struct notifier_block *self, static int __init memory_tier_init(void) { - int node; + int ret, node; struct memory_tier *memtier; + ret = subsys_virtual_register(&memory_tier_subsys, NULL); + if (ret) + panic("%s() failed to register memory tier subsystem\n", __func__); + #ifdef CONFIG_MIGRATION node_demotion = kcalloc(nr_node_ids, sizeof(struct demotion_nodes), GFP_KERNEL);