Re: [PATCH v2] mm/demotion: Expose memory tier details via sysfs

From: Andrew Morton
Date: Mon Aug 29 2022 - 17:01:16 EST


On Mon, 29 Aug 2022 11:37:45 +0530 "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> wrote:

> This patch adds /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
>
> The abstract distance range value of a specific memory tier can be listed via
> /sys/devices/virtual/memory_tiering/memory_tierN/abstract_distance
>
> A directory hierarchy looks like
> :/sys/devices/virtual/memory_tiering$ tree memory_tier4/
> memory_tier4/
> ├── abstract_distance
> ├── nodes
> ├── subsystem -> ../../../../bus/memory_tiering
> └── uevent
>
> All toptier nodes are listed via
> /sys/devices/virtual/memory_tiering/toptier_nodes
>
> :/sys/devices/virtual/memory_tiering$ cat toptier_nodes
> 0,2
> :/sys/devices/virtual/memory_tiering$ cat memory_tier4/nodes
> 0,2
> :/sys/devices/virtual/memory_tiering$ cat memory_tier4/abstract_distance
> 512 - 639
>
> ...
>
> --- 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 +37,13 @@ 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;
> +
> +#define to_memory_tier(device) container_of(device, struct memory_tier, dev)

Please, only use a macro when a C function cannot be used.

--- a/mm/memory-tiers.c~mm-demotion-expose-memory-tier-details-via-sysfs-fix
+++ a/mm/memory-tiers.c
@@ -38,7 +38,11 @@ static LIST_HEAD(memory_tiers);
static struct node_memory_type_map node_memory_types[MAX_NUMNODES];
static struct memory_dev_type *default_dram_type;

-#define to_memory_tier(device) container_of(device, struct memory_tier, dev)
+static inline struct memory_tier *to_memory_tier(struct device *device)
+{
+ return container_of(device, struct memory_tier, dev);
+}
+
static struct bus_type memory_tier_subsys = {
.name = "memory_tiering",
.dev_name = "memory_tier",

If only so it checks the type of `device'.