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mm/demotion: expose memory tier details via sysfs

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Add /sys/devices/virtual/memory_tiering/ where all memory tier related
details can be found.  All allocated memory tiers will be listed there as
/sys/devices/virtual/memory_tiering/memory_tierN/

The nodes which are part of a specific memory tier can be listed via
/sys/devices/virtual/memory_tiering/memory_tierN/nodes

A directory hierarchy looks like
:/sys/devices/virtual/memory_tiering$ tree memory_tier4/
memory_tier4/
├── nodes
├── subsystem -> ../../../../bus/memory_tiering
└── uevent

:/sys/devices/virtual/memory_tiering$ cat memory_tier4/nodes
0,2

[aneesh.kumar@linux.ibm.com: drop toptier_nodes from sysfs]
  Link: https://lkml.kernel.org/r/20220922102201.62168-1-aneesh.kumar@linux.ibm.com
Link: https://lkml.kernel.org/r/20220830081736.119281-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Bharata B Rao <bharata@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hesham Almatary <hesham.almatary@huawei.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Jagdish Gediya <jvgediya.oss@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Aneesh Kumar K.V 2022-08-30 13:47:36 +05:30 committed by Andrew Morton
parent 3e061d924f
commit 9832fb8783
2 changed files with 112 additions and 22 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

25
Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers Normal file
View file

@ -0,0 +1,25 @@
What: /sys/devices/virtual/memory_tiering/
Date: August 2022
Contact: Linux memory management mailing list <linux-mm@kvack.org>
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 <linux-mm@kvack.org>
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.

109
mm/memory-tiers.c
View file

@ -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);