* [PATCH v13 0/9] mm/demotion: Memory tiers and demotion
@ 2022-08-08 6:25 Aneesh Kumar K.V
2022-08-08 6:25 ` [PATCH v13 1/9] mm/demotion: Add support for explicit memory tiers Aneesh Kumar K.V
` (8 more replies)
0 siblings, 9 replies; 21+ messages in thread
From: Aneesh Kumar K.V @ 2022-08-08 6:25 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Wei Xu, Huang Ying, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss, Aneesh Kumar K.V
The current kernel has the basic memory tiering support: Inactive pages on a
higher tier NUMA node can be migrated (demoted) to a lower tier NUMA node to
make room for new allocations on the higher tier NUMA node. Frequently accessed
pages on a lower tier NUMA node can be migrated (promoted) to a higher tier NUMA
node to improve the performance.
In the current kernel, memory tiers are defined implicitly via a demotion path
relationship between NUMA nodes, which is created during the kernel
initialization and updated when a NUMA node is hot-added or hot-removed. The
current implementation puts all nodes with CPU into the highest tier, and builds the
tier hierarchy tier-by-tier by establishing the per-node demotion targets based
on the distances between nodes.
This current memory tier kernel implementation needs to be improved for several
important use cases:
* The current tier initialization code always initializes each memory-only NUMA
node into a lower tier. But a memory-only NUMA node may have a high
performance memory device (e.g. a DRAM-backed memory-only node on a virtual
machine) and that should be put into a higher tier.
* The current tier hierarchy always puts CPU nodes into the top tier. But on a
system with HBM (e.g. GPU memory) devices, these memory-only HBM NUMA nodes
should be in the top tier, and DRAM nodes with CPUs are better to be placed
into the next lower tier.
* Also because the current tier hierarchy always puts CPU nodes into the top
tier, when a CPU is hot-added (or hot-removed) and triggers a memory node from
CPU-less into a CPU node (or vice versa), the memory tier hierarchy gets
changed, even though no memory node is added or removed. This can make the
tier hierarchy unstable and make it difficult to support tier-based memory
accounting.
* A higher tier node can only be demoted to nodes with shortest distance on the
next lower tier as defined by the demotion path, not any other node from any
lower tier. This strict, demotion order does not work in all use
cases (e.g. some use cases may want to allow cross-socket demotion to another
node in the same demotion tier as a fallback when the preferred demotion node
is out of space), and has resulted in the feature request for an interface to
override the system-wide, per-node demotion order from the userspace. This
demotion order is also inconsistent with the page allocation fallback order
when all the nodes in a higher tier are out of space: The page allocation can
fall back to any node from any lower tier, whereas the demotion order doesn't
allow that.
This patch series make the creation of memory tiers explicit under
the control of device driver.
Memory Tier Initialization
==========================
Linux kernel presents memory devices as NUMA nodes and each memory device is of
a specific type. The memory type of a device is represented by its abstract
distance. A memory tier corresponds to a range of abstract distance. This allows
for classifying memory devices with a specific performance range into a memory
tier.
By default, all memory nodes are assigned to the default tier with
abstract distance 512.
A device driver can move its memory nodes from the default tier. For example,
PMEM can move its memory nodes below the default tier, whereas GPU can move its
memory nodes above the default tier.
The kernel initialization code makes the decision on which exact tier a memory
node should be assigned to based on the requests from the device drivers as well
as the memory device hardware information provided by the firmware.
Hot-adding/removing CPUs doesn't affect memory tier hierarchy.
Changes from v12
* Fix kernel crash on module unload
* Address review feedback.
* Add node_random patch to this series based on review feedback
Changes from v11:
* smaller abstract distance imply faster(higher) memory tier.
Changes from v10:
* rename performance level to abstract distance
* Thanks to all the good feedback from Huang, Ying <ying.huang@intel.com>.
Updated the patchset to cover most of the review feedback.
Changes from v9:
* Use performance level for initializing memory tiers.
Changes from v8:
* Drop the sysfs interface patches and related documentation changes.
Changes from v7:
* Fix kernel crash with demotion.
* Improve documentation.
Changes from v6:
* Drop the usage of rank.
* Address other review feedback.
Changes from v5:
* Remove patch supporting N_MEMORY node removal from memory tiers. memory tiers
are going to be used for features other than demotion. Hence keep all N_MEMORY
nodes in memory tiers irrespective of whether they want to participate in promotion or demotion.
* Add NODE_DATA->memtier
* Rearrage patches to add sysfs files later.
* Add support to create memory tiers from userspace.
* Address other review feedback.
Changes from v4:
* Address review feedback.
* Reverse the meaning of "rank": higher rank value means higher tier.
* Add "/sys/devices/system/memtier/default_tier".
* Add node_is_toptier
v4:
Add support for explicit memory tiers and ranks.
v3:
- Modify patch 1 subject to make it more specific
- Remove /sys/kernel/mm/numa/demotion_targets interface, use
/sys/devices/system/node/demotion_targets instead and make
it writable to override node_states[N_DEMOTION_TARGETS].
- Add support to view per node demotion targets via sysfs
v2:
In v1, only 1st patch of this patch series was sent, which was
implemented to avoid some of the limitations on the demotion
target sharing, however for certain numa topology, the demotion
targets found by that patch was not most optimal, so 1st patch
in this series is modified according to suggestions from Huang
and Baolin. Different examples of demotion list comparasion
between existing implementation and changed implementation can
be found in the commit message of 1st patch.
Aneesh Kumar K.V (8):
mm/demotion: Add support for explicit memory tiers
mm/demotion: Move memory demotion related code
mm/demotion: Add hotplug callbacks to handle new numa node onlined
mm/demotion/dax/kmem: Set node's abstract distance to
MEMTIER_DEFAULT_DAX_ADISTANCE
mm/demotion: Build demotion targets based on explicit memory tiers
mm/demotion: Add pg_data_t member to track node memory tier details
mm/demotion: Update node_is_toptier to work with memory tiers
lib/nodemask: Optimize node_random for nodemask with single NUMA node
Jagdish Gediya (1):
mm/demotion: Demote pages according to allocation fallback order
drivers/dax/kmem.c | 40 ++-
include/linux/memory-tiers.h | 84 +++++
include/linux/migrate.h | 15 -
include/linux/mmzone.h | 3 +
include/linux/node.h | 5 -
lib/nodemask.c | 15 +-
mm/Makefile | 1 +
mm/huge_memory.c | 1 +
mm/memory-tiers.c | 616 +++++++++++++++++++++++++++++++++++
mm/migrate.c | 453 +-------------------------
mm/mprotect.c | 1 +
mm/vmscan.c | 59 +++-
mm/vmstat.c | 4 -
13 files changed, 802 insertions(+), 495 deletions(-)
create mode 100644 include/linux/memory-tiers.h
create mode 100644 mm/memory-tiers.c
--
2.37.1
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH v13 1/9] mm/demotion: Add support for explicit memory tiers
2022-08-08 6:25 [PATCH v13 0/9] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
@ 2022-08-08 6:25 ` Aneesh Kumar K.V
2022-08-09 1:58 ` Huang, Ying
2022-08-08 6:25 ` [PATCH v13 2/9] mm/demotion: Move memory demotion related code Aneesh Kumar K.V
` (7 subsequent siblings)
8 siblings, 1 reply; 21+ messages in thread
From: Aneesh Kumar K.V @ 2022-08-08 6:25 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Wei Xu, Huang Ying, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss, Aneesh Kumar K.V
In the current kernel, memory tiers are defined implicitly via a demotion path
relationship between NUMA nodes, which is created during the kernel
initialization and updated when a NUMA node is hot-added or hot-removed. The
current implementation puts all nodes with CPU into the highest tier, and builds
the tier hierarchy by establishing the per-node demotion targets based on the
distances between nodes.
This current memory tier kernel implementation needs to be improved for several
important use cases,
The current tier initialization code always initializes each memory-only NUMA
node into a lower tier. But a memory-only NUMA node may have a high performance
memory device (e.g. a DRAM-backed memory-only node on a virtual machine) that
should be put into a higher tier.
The current tier hierarchy always puts CPU nodes into the top tier. But on a
system with HBM or GPU devices, the memory-only NUMA nodes mapping these devices
should be in the top tier, and DRAM nodes with CPUs are better to be placed into
the next lower tier.
With current kernel higher tier node can only be demoted to nodes with shortest
distance on the next lower tier as defined by the demotion path, not any other
node from any lower tier. This strict, demotion order does not work in all use
cases (e.g. some use cases may want to allow cross-socket demotion to another
node in the same demotion tier as a fallback when the preferred demotion node is
out of space), This demotion order is also inconsistent with the page allocation
fallback order when all the nodes in a higher tier are out of space: The page
allocation can fall back to any node from any lower tier, whereas the demotion
order doesn't allow that.
This patch series address the above by defining memory tiers explicitly.
Linux kernel presents memory devices as NUMA nodes and each memory device is of
a specific type. The memory type of a device is represented by its abstract
distance. A memory tier corresponds to a range of abstract distance. This allows
for classifying memory devices with a specific performance range into a memory
tier.
This patch configures the range/chunk size to be 128. The default DRAM abstract
distance is 512. We can have 4 memory tiers below the default DRAM with abstract
distance range 0 - 127, 127 - 255, 256- 383, 384 - 511. Faster memory devices
can be placed in these faster(higher) memory tiers. Slower memory devices like
persistent memory will have abstract distance higher than the default DRAM
level.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
include/linux/memory-tiers.h | 15 +++++
mm/Makefile | 1 +
mm/memory-tiers.c | 107 +++++++++++++++++++++++++++++++++++
3 files changed, 123 insertions(+)
create mode 100644 include/linux/memory-tiers.h
create mode 100644 mm/memory-tiers.c
diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
new file mode 100644
index 000000000000..bc7c1b799bef
--- /dev/null
+++ b/include/linux/memory-tiers.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MEMORY_TIERS_H
+#define _LINUX_MEMORY_TIERS_H
+
+/*
+ * Each tier cover a abstrace distance chunk size of 128
+ */
+#define MEMTIER_CHUNK_BITS 7
+#define MEMTIER_CHUNK_SIZE (1 << MEMTIER_CHUNK_BITS)
+/*
+ * Smaller abstract distance value imply faster(higher) memory tiers.
+ */
+#define MEMTIER_ADISTANCE_DRAM (4 * MEMTIER_CHUNK_SIZE)
+
+#endif /* _LINUX_MEMORY_TIERS_H */
diff --git a/mm/Makefile b/mm/Makefile
index 6f9ffa968a1a..d30acebc2164 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -92,6 +92,7 @@ obj-$(CONFIG_KFENCE) += kfence/
obj-$(CONFIG_FAILSLAB) += failslab.o
obj-$(CONFIG_MEMTEST) += memtest.o
obj-$(CONFIG_MIGRATION) += migrate.o
+obj-$(CONFIG_NUMA) += memory-tiers.o
obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o
obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
new file mode 100644
index 000000000000..78b311d9bde9
--- /dev/null
+++ b/mm/memory-tiers.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/types.h>
+#include <linux/nodemask.h>
+#include <linux/slab.h>
+#include <linux/lockdep.h>
+#include <linux/memory-tiers.h>
+
+struct memory_tier {
+ /* hierarchy of memory tiers */
+ struct list_head list;
+ /* list of all memory types part of this tier */
+ struct list_head memory_types;
+ /*
+ * start value of abstract distance. memory tier maps
+ * an abstract distance range,
+ * adistance_start .. adistance_start + MEMTIER_CHUNK_SIZE
+ */
+ int adistance_start;
+};
+
+struct memory_dev_type {
+ /* list of memory types that are part of same tier as this type */
+ struct list_head tier_sibiling;
+ /* abstract distance for this specific memory type */
+ int adistance;
+ /* Nodes of same abstract distance */
+ nodemask_t nodes;
+ struct memory_tier *memtier;
+};
+
+static DEFINE_MUTEX(memory_tier_lock);
+static LIST_HEAD(memory_tiers);
+static struct memory_dev_type *node_memory_types[MAX_NUMNODES];
+/*
+ * For now let's have 4 memory tier below default DRAM tier.
+ */
+static struct memory_dev_type default_dram_type = {
+ .adistance = MEMTIER_ADISTANCE_DRAM,
+ .tier_sibiling = LIST_HEAD_INIT(default_dram_type.tier_sibiling),
+};
+
+static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype)
+{
+ bool found_slot = false;
+ struct memory_tier *memtier, *new_memtier;
+ int adistance = memtype->adistance;
+ unsigned int memtier_adistance_chunk_size = MEMTIER_CHUNK_SIZE;
+
+ lockdep_assert_held_once(&memory_tier_lock);
+
+ /*
+ * If the memtype is already part of a memory tier,
+ * just return that.
+ */
+ if (memtype->memtier)
+ return memtype->memtier;
+
+ adistance = round_down(adistance, memtier_adistance_chunk_size);
+ list_for_each_entry(memtier, &memory_tiers, list) {
+ if (adistance == memtier->adistance_start) {
+ memtype->memtier = memtier;
+ list_add(&memtype->tier_sibiling, &memtier->memory_types);
+ return memtier;
+ } else if (adistance < memtier->adistance_start) {
+ found_slot = true;
+ break;
+ }
+ }
+
+ new_memtier = kmalloc(sizeof(struct memory_tier), GFP_KERNEL);
+ if (!new_memtier)
+ return ERR_PTR(-ENOMEM);
+
+ new_memtier->adistance_start = adistance;
+ INIT_LIST_HEAD(&new_memtier->list);
+ INIT_LIST_HEAD(&new_memtier->memory_types);
+ if (found_slot)
+ list_add_tail(&new_memtier->list, &memtier->list);
+ else
+ list_add_tail(&new_memtier->list, &memory_tiers);
+ memtype->memtier = new_memtier;
+ list_add(&memtype->tier_sibiling, &new_memtier->memory_types);
+ return new_memtier;
+}
+
+static int __init memory_tier_init(void)
+{
+ int node;
+ struct memory_tier *memtier;
+
+ mutex_lock(&memory_tier_lock);
+ /* CPU only nodes are not part of memory tiers. */
+ default_dram_type.nodes = node_states[N_MEMORY];
+
+ memtier = find_create_memory_tier(&default_dram_type);
+ if (IS_ERR(memtier))
+ panic("%s() failed to register memory tier: %ld\n",
+ __func__, PTR_ERR(memtier));
+
+ for_each_node_state(node, N_MEMORY)
+ node_memory_types[node] = &default_dram_type;
+
+ mutex_unlock(&memory_tier_lock);
+
+ return 0;
+}
+subsys_initcall(memory_tier_init);
--
2.37.1
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH v13 2/9] mm/demotion: Move memory demotion related code
2022-08-08 6:25 [PATCH v13 0/9] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
2022-08-08 6:25 ` [PATCH v13 1/9] mm/demotion: Add support for explicit memory tiers Aneesh Kumar K.V
@ 2022-08-08 6:25 ` Aneesh Kumar K.V
2022-08-08 6:25 ` [PATCH v13 3/9] mm/demotion: Add hotplug callbacks to handle new numa node onlined Aneesh Kumar K.V
` (6 subsequent siblings)
8 siblings, 0 replies; 21+ messages in thread
From: Aneesh Kumar K.V @ 2022-08-08 6:25 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Wei Xu, Huang Ying, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss, Aneesh Kumar K.V
This move memory demotion related code to mm/memory-tiers.c.
No functional change in this patch.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
include/linux/memory-tiers.h | 8 +++++
include/linux/migrate.h | 2 --
mm/memory-tiers.c | 64 ++++++++++++++++++++++++++++++++++++
mm/migrate.c | 60 +--------------------------------
mm/vmscan.c | 1 +
5 files changed, 74 insertions(+), 61 deletions(-)
diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index bc7c1b799bef..9fdd9572fdf9 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -12,4 +12,12 @@
*/
#define MEMTIER_ADISTANCE_DRAM (4 * MEMTIER_CHUNK_SIZE)
+#ifdef CONFIG_NUMA
+#include <linux/types.h>
+extern bool numa_demotion_enabled;
+
+#else
+
+#define numa_demotion_enabled false
+#endif /* CONFIG_NUMA */
#endif /* _LINUX_MEMORY_TIERS_H */
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index ae5bb67a9ba1..4b07c5ef3903 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -103,7 +103,6 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
#if defined(CONFIG_MIGRATION) && defined(CONFIG_NUMA)
extern void set_migration_target_nodes(void);
extern void migrate_on_reclaim_init(void);
-extern bool numa_demotion_enabled;
extern int next_demotion_node(int node);
#else
static inline void set_migration_target_nodes(void) {}
@@ -112,7 +111,6 @@ static inline int next_demotion_node(int node)
{
return NUMA_NO_NODE;
}
-#define numa_demotion_enabled false
#endif
#ifdef CONFIG_COMPACTION
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 78b311d9bde9..391b36ee7afe 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -3,6 +3,8 @@
#include <linux/nodemask.h>
#include <linux/slab.h>
#include <linux/lockdep.h>
+#include <linux/sysfs.h>
+#include <linux/kobject.h>
#include <linux/memory-tiers.h>
struct memory_tier {
@@ -105,3 +107,65 @@ static int __init memory_tier_init(void)
return 0;
}
subsys_initcall(memory_tier_init);
+
+bool numa_demotion_enabled = false;
+
+#ifdef CONFIG_MIGRATION
+#ifdef CONFIG_SYSFS
+static ssize_t numa_demotion_enabled_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return sysfs_emit(buf, "%s\n",
+ numa_demotion_enabled ? "true" : "false");
+}
+
+static ssize_t numa_demotion_enabled_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ ssize_t ret;
+
+ ret = kstrtobool(buf, &numa_demotion_enabled);
+ if (ret)
+ return ret;
+
+ return count;
+}
+
+static struct kobj_attribute numa_demotion_enabled_attr =
+ __ATTR(demotion_enabled, 0644, numa_demotion_enabled_show,
+ numa_demotion_enabled_store);
+
+static struct attribute *numa_attrs[] = {
+ &numa_demotion_enabled_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group numa_attr_group = {
+ .attrs = numa_attrs,
+};
+
+static int __init numa_init_sysfs(void)
+{
+ int err;
+ struct kobject *numa_kobj;
+
+ numa_kobj = kobject_create_and_add("numa", mm_kobj);
+ if (!numa_kobj) {
+ pr_err("failed to create numa kobject\n");
+ return -ENOMEM;
+ }
+ err = sysfs_create_group(numa_kobj, &numa_attr_group);
+ if (err) {
+ pr_err("failed to register numa group\n");
+ goto delete_obj;
+ }
+ return 0;
+
+delete_obj:
+ kobject_put(numa_kobj);
+ return err;
+}
+subsys_initcall(numa_init_sysfs);
+#endif /* CONFIG_SYSFS */
+#endif
diff --git a/mm/migrate.c b/mm/migrate.c
index 1b4b977809a1..774225c45354 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2551,64 +2551,6 @@ void __init migrate_on_reclaim_init(void)
set_migration_target_nodes();
cpus_read_unlock();
}
+#endif /* CONFIG_NUMA */
-bool numa_demotion_enabled = false;
-
-#ifdef CONFIG_SYSFS
-static ssize_t numa_demotion_enabled_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
-{
- return sysfs_emit(buf, "%s\n",
- numa_demotion_enabled ? "true" : "false");
-}
-
-static ssize_t numa_demotion_enabled_store(struct kobject *kobj,
- struct kobj_attribute *attr,
- const char *buf, size_t count)
-{
- ssize_t ret;
-
- ret = kstrtobool(buf, &numa_demotion_enabled);
- if (ret)
- return ret;
-
- return count;
-}
-
-static struct kobj_attribute numa_demotion_enabled_attr =
- __ATTR(demotion_enabled, 0644, numa_demotion_enabled_show,
- numa_demotion_enabled_store);
-
-static struct attribute *numa_attrs[] = {
- &numa_demotion_enabled_attr.attr,
- NULL,
-};
-
-static const struct attribute_group numa_attr_group = {
- .attrs = numa_attrs,
-};
-
-static int __init numa_init_sysfs(void)
-{
- int err;
- struct kobject *numa_kobj;
- numa_kobj = kobject_create_and_add("numa", mm_kobj);
- if (!numa_kobj) {
- pr_err("failed to create numa kobject\n");
- return -ENOMEM;
- }
- err = sysfs_create_group(numa_kobj, &numa_attr_group);
- if (err) {
- pr_err("failed to register numa group\n");
- goto delete_obj;
- }
- return 0;
-
-delete_obj:
- kobject_put(numa_kobj);
- return err;
-}
-subsys_initcall(numa_init_sysfs);
-#endif /* CONFIG_SYSFS */
-#endif /* CONFIG_NUMA */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 04f8671caad9..5043b10ff71e 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -50,6 +50,7 @@
#include <linux/printk.h>
#include <linux/dax.h>
#include <linux/psi.h>
+#include <linux/memory-tiers.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
--
2.37.1
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH v13 3/9] mm/demotion: Add hotplug callbacks to handle new numa node onlined
2022-08-08 6:25 [PATCH v13 0/9] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
2022-08-08 6:25 ` [PATCH v13 1/9] mm/demotion: Add support for explicit memory tiers Aneesh Kumar K.V
2022-08-08 6:25 ` [PATCH v13 2/9] mm/demotion: Move memory demotion related code Aneesh Kumar K.V
@ 2022-08-08 6:25 ` Aneesh Kumar K.V
2022-08-08 6:25 ` [PATCH v13 4/9] mm/demotion/dax/kmem: Set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE Aneesh Kumar K.V
` (5 subsequent siblings)
8 siblings, 0 replies; 21+ messages in thread
From: Aneesh Kumar K.V @ 2022-08-08 6:25 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Wei Xu, Huang Ying, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss, Aneesh Kumar K.V
If the new NUMA node onlined doesn't have a abstract distance assigned,
the kernel adds the NUMA node to default memory tier.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
include/linux/memory-tiers.h | 1 +
mm/memory-tiers.c | 87 ++++++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+)
diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index 9fdd9572fdf9..cc89876899a6 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -11,6 +11,7 @@
* Smaller abstract distance value imply faster(higher) memory tiers.
*/
#define MEMTIER_ADISTANCE_DRAM (4 * MEMTIER_CHUNK_SIZE)
+#define MEMTIER_HOTPLUG_PRIO 100
#ifdef CONFIG_NUMA
#include <linux/types.h>
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 391b36ee7afe..2caa5ab446b8 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -5,6 +5,7 @@
#include <linux/lockdep.h>
#include <linux/sysfs.h>
#include <linux/kobject.h>
+#include <linux/memory.h>
#include <linux/memory-tiers.h>
struct memory_tier {
@@ -85,6 +86,91 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
return new_memtier;
}
+static struct memory_tier *__node_get_memory_tier(int node)
+{
+ struct memory_dev_type *memtype;
+
+ memtype = node_memory_types[node];
+ if (memtype && node_isset(node, memtype->nodes))
+ return memtype->memtier;
+ return NULL;
+}
+
+static struct memory_tier *set_node_memory_tier(int node)
+{
+ struct memory_tier *memtier;
+ struct memory_dev_type *memtype;
+
+ lockdep_assert_held_once(&memory_tier_lock);
+
+ if (!node_state(node, N_MEMORY))
+ return ERR_PTR(-EINVAL);
+
+ if (!node_memory_types[node])
+ node_memory_types[node] = &default_dram_type;
+
+ memtype = node_memory_types[node];
+ node_set(node, memtype->nodes);
+ memtier = find_create_memory_tier(memtype);
+ return memtier;
+}
+
+static void destroy_memory_tier(struct memory_tier *memtier)
+{
+ list_del(&memtier->list);
+ kfree(memtier);
+}
+
+static bool clear_node_memory_tier(int node)
+{
+ bool cleared = false;
+ struct memory_tier *memtier;
+
+ memtier = __node_get_memory_tier(node);
+ if (memtier) {
+ struct memory_dev_type *memtype;
+
+ memtype = node_memory_types[node];
+ node_clear(node, memtype->nodes);
+ if (nodes_empty(memtype->nodes)) {
+ list_del(&memtype->tier_sibiling);
+ memtype->memtier = NULL;
+ if (list_empty(&memtier->memory_types))
+ destroy_memory_tier(memtier);
+ }
+ cleared = true;
+ }
+ return cleared;
+}
+
+static int __meminit memtier_hotplug_callback(struct notifier_block *self,
+ unsigned long action, void *_arg)
+{
+ struct memory_notify *arg = _arg;
+
+ /*
+ * Only update the node migration order when a node is
+ * changing status, like online->offline.
+ */
+ if (arg->status_change_nid < 0)
+ return notifier_from_errno(0);
+
+ switch (action) {
+ case MEM_OFFLINE:
+ mutex_lock(&memory_tier_lock);
+ clear_node_memory_tier(arg->status_change_nid);
+ mutex_unlock(&memory_tier_lock);
+ break;
+ case MEM_ONLINE:
+ mutex_lock(&memory_tier_lock);
+ set_node_memory_tier(arg->status_change_nid);
+ mutex_unlock(&memory_tier_lock);
+ break;
+ }
+
+ return notifier_from_errno(0);
+}
+
static int __init memory_tier_init(void)
{
int node;
@@ -104,6 +190,7 @@ static int __init memory_tier_init(void)
mutex_unlock(&memory_tier_lock);
+ hotplug_memory_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_PRIO);
return 0;
}
subsys_initcall(memory_tier_init);
--
2.37.1
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH v13 4/9] mm/demotion/dax/kmem: Set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE
2022-08-08 6:25 [PATCH v13 0/9] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
` (2 preceding siblings ...)
2022-08-08 6:25 ` [PATCH v13 3/9] mm/demotion: Add hotplug callbacks to handle new numa node onlined Aneesh Kumar K.V
@ 2022-08-08 6:25 ` Aneesh Kumar K.V
2022-08-09 3:04 ` Huang, Ying
2022-08-08 6:25 ` [PATCH v13 5/9] mm/demotion: Build demotion targets based on explicit memory tiers Aneesh Kumar K.V
` (4 subsequent siblings)
8 siblings, 1 reply; 21+ messages in thread
From: Aneesh Kumar K.V @ 2022-08-08 6:25 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Wei Xu, Huang Ying, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss, Aneesh Kumar K.V
By default, all nodes are assigned to the default memory tier which
is the memory tier designated for nodes with DRAM
Set dax kmem device node's tier to slower memory tier by assigning
abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE. Low-level drivers
like papr_scm or ACPI NFIT can initialize memory device type to a
more accurate value based on device tree details or HMAT. If the
kernel doesn't find the memory type initialized, a default slower
memory type is assigned by the kmem driver.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
drivers/dax/kmem.c | 40 ++++++++++++++++++-
include/linux/memory-tiers.h | 26 ++++++++++++-
mm/memory-tiers.c | 74 +++++++++++++++++++++++++-----------
3 files changed, 115 insertions(+), 25 deletions(-)
diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index a37622060fff..b5cb03307af8 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -11,9 +11,17 @@
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mman.h>
+#include <linux/memory-tiers.h>
#include "dax-private.h"
#include "bus.h"
+/*
+ * Default abstract distance assigned to the NUMA node onlined
+ * by DAX/kmem if the low level platform driver didn't initialize
+ * one for this NUMA node.
+ */
+#define MEMTIER_DEFAULT_DAX_ADISTANCE (MEMTIER_ADISTANCE_DRAM * 2)
+
/* Memory resource name used for add_memory_driver_managed(). */
static const char *kmem_name;
/* Set if any memory will remain added when the driver will be unloaded. */
@@ -41,6 +49,7 @@ struct dax_kmem_data {
struct resource *res[];
};
+static struct memory_dev_type *dax_slowmem_type;
static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
{
struct device *dev = &dev_dax->dev;
@@ -62,6 +71,8 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
return -EINVAL;
}
+ init_node_memory_type(numa_node, dax_slowmem_type);
+
for (i = 0; i < dev_dax->nr_range; i++) {
struct range range;
@@ -162,6 +173,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
{
int i, success = 0;
+ int node = dev_dax->target_node;
struct device *dev = &dev_dax->dev;
struct dax_kmem_data *data = dev_get_drvdata(dev);
@@ -198,6 +210,14 @@ static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
kfree(data->res_name);
kfree(data);
dev_set_drvdata(dev, NULL);
+ /*
+ * Clear the memtype association on successful unplug.
+ * If not, we have memory blocks left which can be
+ * offlined/onlined later. We need to keep memory_dev_type
+ * for that. This implies this reference will be around
+ * till next reboot.
+ */
+ clear_node_memory_type(node, dax_slowmem_type);
}
}
#else
@@ -228,9 +248,27 @@ static int __init dax_kmem_init(void)
if (!kmem_name)
return -ENOMEM;
+ dax_slowmem_type = kmalloc(sizeof(*dax_slowmem_type), GFP_KERNEL);
+ if (!dax_slowmem_type) {
+ rc = -ENOMEM;
+ goto kmem_name_free;
+ }
+ dax_slowmem_type->adistance = MEMTIER_DEFAULT_DAX_ADISTANCE;
+ INIT_LIST_HEAD(&dax_slowmem_type->tier_sibiling);
+ dax_slowmem_type->nodes = NODE_MASK_NONE;
+ dax_slowmem_type->memtier = NULL;
+ kref_init(&dax_slowmem_type->kref);
+
rc = dax_driver_register(&device_dax_kmem_driver);
if (rc)
- kfree_const(kmem_name);
+ goto error_out;
+
+ return rc;
+
+error_out:
+ kfree(dax_slowmem_type);
+kmem_name_free:
+ kfree_const(kmem_name);
return rc;
}
diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index cc89876899a6..7bf6f47d581a 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -2,6 +2,8 @@
#ifndef _LINUX_MEMORY_TIERS_H
#define _LINUX_MEMORY_TIERS_H
+#include <linux/types.h>
+#include <linux/nodemask.h>
/*
* Each tier cover a abstrace distance chunk size of 128
*/
@@ -13,12 +15,34 @@
#define MEMTIER_ADISTANCE_DRAM (4 * MEMTIER_CHUNK_SIZE)
#define MEMTIER_HOTPLUG_PRIO 100
+struct memory_tier;
+struct memory_dev_type {
+ /* list of memory types that are part of same tier as this type */
+ struct list_head tier_sibiling;
+ /* abstract distance for this specific memory type */
+ int adistance;
+ /* Nodes of same abstract distance */
+ nodemask_t nodes;
+ struct kref kref;
+ struct memory_tier *memtier;
+};
+
#ifdef CONFIG_NUMA
-#include <linux/types.h>
extern bool numa_demotion_enabled;
+void init_node_memory_type(int node, struct memory_dev_type *default_type);
+void clear_node_memory_type(int node, struct memory_dev_type *memtype);
#else
#define numa_demotion_enabled false
+static inline void init_node_memory_type(int node, struct memory_dev_type *default_type)
+{
+
+}
+
+static inline void clear_node_memory_type(int node, struct memory_dev_type *memtype)
+{
+
+}
#endif /* CONFIG_NUMA */
#endif /* _LINUX_MEMORY_TIERS_H */
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 2caa5ab446b8..e07dffb67567 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -1,6 +1,4 @@
// SPDX-License-Identifier: GPL-2.0
-#include <linux/types.h>
-#include <linux/nodemask.h>
#include <linux/slab.h>
#include <linux/lockdep.h>
#include <linux/sysfs.h>
@@ -21,26 +19,10 @@ struct memory_tier {
int adistance_start;
};
-struct memory_dev_type {
- /* list of memory types that are part of same tier as this type */
- struct list_head tier_sibiling;
- /* abstract distance for this specific memory type */
- int adistance;
- /* Nodes of same abstract distance */
- nodemask_t nodes;
- struct memory_tier *memtier;
-};
-
static DEFINE_MUTEX(memory_tier_lock);
static LIST_HEAD(memory_tiers);
static struct memory_dev_type *node_memory_types[MAX_NUMNODES];
-/*
- * For now let's have 4 memory tier below default DRAM tier.
- */
-static struct memory_dev_type default_dram_type = {
- .adistance = MEMTIER_ADISTANCE_DRAM,
- .tier_sibiling = LIST_HEAD_INIT(default_dram_type.tier_sibiling),
-};
+static struct memory_dev_type *default_dram_type;
static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype)
{
@@ -96,6 +78,14 @@ static struct memory_tier *__node_get_memory_tier(int node)
return NULL;
}
+static inline void __init_node_memory_type(int node, struct memory_dev_type *default_type)
+{
+ if (!node_memory_types[node]) {
+ node_memory_types[node] = default_type;
+ kref_get(&default_type->kref);
+ }
+}
+
static struct memory_tier *set_node_memory_tier(int node)
{
struct memory_tier *memtier;
@@ -107,7 +97,7 @@ static struct memory_tier *set_node_memory_tier(int node)
return ERR_PTR(-EINVAL);
if (!node_memory_types[node])
- node_memory_types[node] = &default_dram_type;
+ __init_node_memory_type(node, default_dram_type);
memtype = node_memory_types[node];
node_set(node, memtype->nodes);
@@ -143,6 +133,34 @@ static bool clear_node_memory_tier(int node)
return cleared;
}
+void init_node_memory_type(int node, struct memory_dev_type *default_type)
+{
+
+ mutex_lock(&memory_tier_lock);
+ __init_node_memory_type(node, default_type);
+ mutex_unlock(&memory_tier_lock);
+}
+EXPORT_SYMBOL_GPL(init_node_memory_type);
+
+static void release_memtype(struct kref *kref)
+{
+ struct memory_dev_type *memtype;
+
+ memtype = container_of(kref, struct memory_dev_type, kref);
+ kfree(memtype);
+}
+
+void clear_node_memory_type(int node, struct memory_dev_type *memtype)
+{
+ mutex_lock(&memory_tier_lock);
+ if (node_memory_types[node] == memtype) {
+ node_memory_types[node] = NULL;
+ kref_put(&memtype->kref, release_memtype);
+ }
+ mutex_unlock(&memory_tier_lock);
+}
+EXPORT_SYMBOL_GPL(clear_node_memory_type);
+
static int __meminit memtier_hotplug_callback(struct notifier_block *self,
unsigned long action, void *_arg)
{
@@ -176,17 +194,27 @@ static int __init memory_tier_init(void)
int node;
struct memory_tier *memtier;
+ default_dram_type = kmalloc(sizeof(*default_dram_type), GFP_KERNEL);
+ if (!default_dram_type)
+ panic("%s() failed to allocate default DRAM tier\n", __func__);
+
mutex_lock(&memory_tier_lock);
+
+ /* For now let's have 4 memory tier below default DRAM tier. */
+ default_dram_type->adistance = MEMTIER_ADISTANCE_DRAM;
+ INIT_LIST_HEAD(&default_dram_type->tier_sibiling);
+ default_dram_type->memtier = NULL;
+ kref_init(&default_dram_type->kref);
/* CPU only nodes are not part of memory tiers. */
- default_dram_type.nodes = node_states[N_MEMORY];
+ default_dram_type->nodes = node_states[N_MEMORY];
- memtier = find_create_memory_tier(&default_dram_type);
+ memtier = find_create_memory_tier(default_dram_type);
if (IS_ERR(memtier))
panic("%s() failed to register memory tier: %ld\n",
__func__, PTR_ERR(memtier));
for_each_node_state(node, N_MEMORY)
- node_memory_types[node] = &default_dram_type;
+ __init_node_memory_type(node, default_dram_type);
mutex_unlock(&memory_tier_lock);
--
2.37.1
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH v13 5/9] mm/demotion: Build demotion targets based on explicit memory tiers
2022-08-08 6:25 [PATCH v13 0/9] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
` (3 preceding siblings ...)
2022-08-08 6:25 ` [PATCH v13 4/9] mm/demotion/dax/kmem: Set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE Aneesh Kumar K.V
@ 2022-08-08 6:25 ` Aneesh Kumar K.V
2022-08-08 6:25 ` [PATCH v13 6/9] mm/demotion: Add pg_data_t member to track node memory tier details Aneesh Kumar K.V
` (3 subsequent siblings)
8 siblings, 0 replies; 21+ messages in thread
From: Aneesh Kumar K.V @ 2022-08-08 6:25 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Wei Xu, Huang Ying, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss, Aneesh Kumar K.V
This patch switch the demotion target building logic to use memory tiers
instead of NUMA distance. All N_MEMORY NUMA nodes will be placed in the
default memory tier and additional memory tiers will be added by drivers like
dax kmem.
This patch builds the demotion target for a NUMA node by looking at all
memory tiers below the tier to which the NUMA node belongs. The closest node
in the immediately following memory tier is used as a demotion target.
Since we are now only building demotion target for N_MEMORY NUMA nodes
the CPU hotplug calls are removed in this patch.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
include/linux/memory-tiers.h | 13 ++
include/linux/migrate.h | 13 --
mm/memory-tiers.c | 219 ++++++++++++++++++-
mm/migrate.c | 394 -----------------------------------
mm/vmstat.c | 4 -
5 files changed, 229 insertions(+), 414 deletions(-)
diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index 7bf6f47d581a..c8cd593fa2df 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -31,6 +31,14 @@ struct memory_dev_type {
extern bool numa_demotion_enabled;
void init_node_memory_type(int node, struct memory_dev_type *default_type);
void clear_node_memory_type(int node, struct memory_dev_type *memtype);
+#ifdef CONFIG_MIGRATION
+int next_demotion_node(int node);
+#else
+static inline int next_demotion_node(int node)
+{
+ return NUMA_NO_NODE;
+}
+#endif
#else
@@ -44,5 +52,10 @@ static inline void clear_node_memory_type(int node, struct memory_dev_type *memt
{
}
+
+static inline int next_demotion_node(int node)
+{
+ return NUMA_NO_NODE;
+}
#endif /* CONFIG_NUMA */
#endif /* _LINUX_MEMORY_TIERS_H */
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 4b07c5ef3903..c09880a6e1d2 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -100,19 +100,6 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
#endif /* CONFIG_MIGRATION */
-#if defined(CONFIG_MIGRATION) && defined(CONFIG_NUMA)
-extern void set_migration_target_nodes(void);
-extern void migrate_on_reclaim_init(void);
-extern int next_demotion_node(int node);
-#else
-static inline void set_migration_target_nodes(void) {}
-static inline void migrate_on_reclaim_init(void) {}
-static inline int next_demotion_node(int node)
-{
- return NUMA_NO_NODE;
-}
-#endif
-
#ifdef CONFIG_COMPACTION
bool PageMovable(struct page *page);
void __SetPageMovable(struct page *page, const struct movable_operations *ops);
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index e07dffb67567..02e514e87d5c 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -4,8 +4,11 @@
#include <linux/sysfs.h>
#include <linux/kobject.h>
#include <linux/memory.h>
+#include <linux/random.h>
#include <linux/memory-tiers.h>
+#include "internal.h"
+
struct memory_tier {
/* hierarchy of memory tiers */
struct list_head list;
@@ -19,10 +22,74 @@ struct memory_tier {
int adistance_start;
};
+struct demotion_nodes {
+ nodemask_t preferred;
+};
+
static DEFINE_MUTEX(memory_tier_lock);
static LIST_HEAD(memory_tiers);
static struct memory_dev_type *node_memory_types[MAX_NUMNODES];
static struct memory_dev_type *default_dram_type;
+#ifdef CONFIG_MIGRATION
+/*
+ * node_demotion[] examples:
+ *
+ * Example 1:
+ *
+ * Node 0 & 1 are CPU + DRAM nodes, node 2 & 3 are PMEM nodes.
+ *
+ * node distances:
+ * node 0 1 2 3
+ * 0 10 20 30 40
+ * 1 20 10 40 30
+ * 2 30 40 10 40
+ * 3 40 30 40 10
+ *
+ * memory_tiers0 = 0-1
+ * memory_tiers1 = 2-3
+ *
+ * node_demotion[0].preferred = 2
+ * node_demotion[1].preferred = 3
+ * node_demotion[2].preferred = <empty>
+ * node_demotion[3].preferred = <empty>
+ *
+ * Example 2:
+ *
+ * Node 0 & 1 are CPU + DRAM nodes, node 2 is memory-only DRAM node.
+ *
+ * node distances:
+ * node 0 1 2
+ * 0 10 20 30
+ * 1 20 10 30
+ * 2 30 30 10
+ *
+ * memory_tiers0 = 0-2
+ *
+ * node_demotion[0].preferred = <empty>
+ * node_demotion[1].preferred = <empty>
+ * node_demotion[2].preferred = <empty>
+ *
+ * Example 3:
+ *
+ * Node 0 is CPU + DRAM nodes, Node 1 is HBM node, node 2 is PMEM node.
+ *
+ * node distances:
+ * node 0 1 2
+ * 0 10 20 30
+ * 1 20 10 40
+ * 2 30 40 10
+ *
+ * memory_tiers0 = 1
+ * memory_tiers1 = 0
+ * memory_tiers2 = 2
+ *
+ * node_demotion[0].preferred = 2
+ * node_demotion[1].preferred = 0
+ * node_demotion[2].preferred = <empty>
+ *
+ */
+static struct demotion_nodes *node_demotion __read_mostly;
+#endif /* CONFIG_MIGRATION */
static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype)
{
@@ -78,6 +145,144 @@ static struct memory_tier *__node_get_memory_tier(int node)
return NULL;
}
+#ifdef CONFIG_MIGRATION
+/**
+ * next_demotion_node() - Get the next node in the demotion path
+ * @node: The starting node to lookup the next node
+ *
+ * Return: node id for next memory node in the demotion path hierarchy
+ * from @node; NUMA_NO_NODE if @node is terminal. This does not keep
+ * @node online or guarantee that it *continues* to be the next demotion
+ * target.
+ */
+int next_demotion_node(int node)
+{
+ struct demotion_nodes *nd;
+ int target;
+
+ if (!node_demotion)
+ return NUMA_NO_NODE;
+
+ nd = &node_demotion[node];
+
+ /*
+ * node_demotion[] is updated without excluding this
+ * function from running.
+ *
+ * Make sure to use RCU over entire code blocks if
+ * node_demotion[] reads need to be consistent.
+ */
+ rcu_read_lock();
+ /*
+ * If there are multiple target nodes, just select one
+ * target node randomly.
+ *
+ * In addition, we can also use round-robin to select
+ * target node, but we should introduce another variable
+ * for node_demotion[] to record last selected target node,
+ * that may cause cache ping-pong due to the changing of
+ * last target node. Or introducing per-cpu data to avoid
+ * caching issue, which seems more complicated. So selecting
+ * target node randomly seems better until now.
+ */
+ target = node_random(&nd->preferred);
+ rcu_read_unlock();
+
+ return target;
+}
+
+static void disable_all_demotion_targets(void)
+{
+ int node;
+
+ for_each_node_state(node, N_MEMORY)
+ node_demotion[node].preferred = NODE_MASK_NONE;
+ /*
+ * Ensure that the "disable" is visible across the system.
+ * Readers will see either a combination of before+disable
+ * state or disable+after. They will never see before and
+ * after state together.
+ */
+ 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
+ * being at the end of a chain.
+ */
+static void establish_demotion_targets(void)
+{
+ struct memory_tier *memtier;
+ struct demotion_nodes *nd;
+ int target = NUMA_NO_NODE, node;
+ int distance, best_distance;
+ nodemask_t tier_nodes;
+
+ lockdep_assert_held_once(&memory_tier_lock);
+
+ if (!node_demotion || !IS_ENABLED(CONFIG_MIGRATION))
+ return;
+
+ disable_all_demotion_targets();
+
+ for_each_node_state(node, N_MEMORY) {
+ best_distance = -1;
+ nd = &node_demotion[node];
+
+ memtier = __node_get_memory_tier(node);
+ if (!memtier || list_is_last(&memtier->list, &memory_tiers))
+ continue;
+ /*
+ * Get the lower memtier to find the demotion node list.
+ */
+ memtier = list_next_entry(memtier, list);
+ tier_nodes = get_memtier_nodemask(memtier);
+ /*
+ * find_next_best_node, use 'used' nodemask as a skip list.
+ * Add all memory nodes except the selected memory tier
+ * nodelist to skip list so that we find the best node from the
+ * memtier nodelist.
+ */
+ nodes_andnot(tier_nodes, node_states[N_MEMORY], tier_nodes);
+
+ /*
+ * Find all the nodes in the memory tier node list of same best distance.
+ * add them to the preferred mask. We randomly select between nodes
+ * in the preferred mask when allocating pages during demotion.
+ */
+ do {
+ target = find_next_best_node(node, &tier_nodes);
+ if (target == NUMA_NO_NODE)
+ break;
+
+ distance = node_distance(node, target);
+ if (distance == best_distance || best_distance == -1) {
+ best_distance = distance;
+ node_set(target, nd->preferred);
+ } else {
+ break;
+ }
+ } while (1);
+ }
+}
+
+#else
+static inline void disable_all_demotion_targets(void) {}
+static inline void establish_demotion_targets(void) {}
+#endif /* CONFIG_MIGRATION */
+
static inline void __init_node_memory_type(int node, struct memory_dev_type *default_type)
{
if (!node_memory_types[node]) {
@@ -164,6 +369,7 @@ EXPORT_SYMBOL_GPL(clear_node_memory_type);
static int __meminit memtier_hotplug_callback(struct notifier_block *self,
unsigned long action, void *_arg)
{
+ struct memory_tier *memtier;
struct memory_notify *arg = _arg;
/*
@@ -176,12 +382,15 @@ static int __meminit memtier_hotplug_callback(struct notifier_block *self,
switch (action) {
case MEM_OFFLINE:
mutex_lock(&memory_tier_lock);
- clear_node_memory_tier(arg->status_change_nid);
+ if (clear_node_memory_tier(arg->status_change_nid))
+ establish_demotion_targets();
mutex_unlock(&memory_tier_lock);
break;
case MEM_ONLINE:
mutex_lock(&memory_tier_lock);
- set_node_memory_tier(arg->status_change_nid);
+ memtier = set_node_memory_tier(arg->status_change_nid);
+ if (!IS_ERR(memtier))
+ establish_demotion_targets();
mutex_unlock(&memory_tier_lock);
break;
}
@@ -217,7 +426,11 @@ static int __init memory_tier_init(void)
__init_node_memory_type(node, default_dram_type);
mutex_unlock(&memory_tier_lock);
-
+#ifdef CONFIG_MIGRATION
+ node_demotion = kcalloc(nr_node_ids, sizeof(struct demotion_nodes),
+ GFP_KERNEL);
+ WARN_ON(!node_demotion);
+#endif
hotplug_memory_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_PRIO);
return 0;
}
diff --git a/mm/migrate.c b/mm/migrate.c
index 774225c45354..45290ddd3806 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2159,398 +2159,4 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
return 0;
}
#endif /* CONFIG_NUMA_BALANCING */
-
-/*
- * node_demotion[] example:
- *
- * Consider a system with two sockets. Each socket has
- * three classes of memory attached: fast, medium and slow.
- * Each memory class is placed in its own NUMA node. The
- * CPUs are placed in the node with the "fast" memory. The
- * 6 NUMA nodes (0-5) might be split among the sockets like
- * this:
- *
- * Socket A: 0, 1, 2
- * Socket B: 3, 4, 5
- *
- * When Node 0 fills up, its memory should be migrated to
- * Node 1. When Node 1 fills up, it should be migrated to
- * Node 2. The migration path start on the nodes with the
- * processors (since allocations default to this node) and
- * fast memory, progress through medium and end with the
- * slow memory:
- *
- * 0 -> 1 -> 2 -> stop
- * 3 -> 4 -> 5 -> stop
- *
- * This is represented in the node_demotion[] like this:
- *
- * { nr=1, nodes[0]=1 }, // Node 0 migrates to 1
- * { nr=1, nodes[0]=2 }, // Node 1 migrates to 2
- * { nr=0, nodes[0]=-1 }, // Node 2 does not migrate
- * { nr=1, nodes[0]=4 }, // Node 3 migrates to 4
- * { nr=1, nodes[0]=5 }, // Node 4 migrates to 5
- * { nr=0, nodes[0]=-1 }, // Node 5 does not migrate
- *
- * Moreover some systems may have multiple slow memory nodes.
- * Suppose a system has one socket with 3 memory nodes, node 0
- * is fast memory type, and node 1/2 both are slow memory
- * type, and the distance between fast memory node and slow
- * memory node is same. So the migration path should be:
- *
- * 0 -> 1/2 -> stop
- *
- * This is represented in the node_demotion[] like this:
- * { nr=2, {nodes[0]=1, nodes[1]=2} }, // Node 0 migrates to node 1 and node 2
- * { nr=0, nodes[0]=-1, }, // Node 1 dose not migrate
- * { nr=0, nodes[0]=-1, }, // Node 2 does not migrate
- */
-
-/*
- * Writes to this array occur without locking. Cycles are
- * not allowed: Node X demotes to Y which demotes to X...
- *
- * If multiple reads are performed, a single rcu_read_lock()
- * must be held over all reads to ensure that no cycles are
- * observed.
- */
-#define DEFAULT_DEMOTION_TARGET_NODES 15
-
-#if MAX_NUMNODES < DEFAULT_DEMOTION_TARGET_NODES
-#define DEMOTION_TARGET_NODES (MAX_NUMNODES - 1)
-#else
-#define DEMOTION_TARGET_NODES DEFAULT_DEMOTION_TARGET_NODES
-#endif
-
-struct demotion_nodes {
- unsigned short nr;
- short nodes[DEMOTION_TARGET_NODES];
-};
-
-static struct demotion_nodes *node_demotion __read_mostly;
-
-/**
- * next_demotion_node() - Get the next node in the demotion path
- * @node: The starting node to lookup the next node
- *
- * Return: node id for next memory node in the demotion path hierarchy
- * from @node; NUMA_NO_NODE if @node is terminal. This does not keep
- * @node online or guarantee that it *continues* to be the next demotion
- * target.
- */
-int next_demotion_node(int node)
-{
- struct demotion_nodes *nd;
- unsigned short target_nr, index;
- int target;
-
- if (!node_demotion)
- return NUMA_NO_NODE;
-
- nd = &node_demotion[node];
-
- /*
- * node_demotion[] is updated without excluding this
- * function from running. RCU doesn't provide any
- * compiler barriers, so the READ_ONCE() is required
- * to avoid compiler reordering or read merging.
- *
- * Make sure to use RCU over entire code blocks if
- * node_demotion[] reads need to be consistent.
- */
- rcu_read_lock();
- target_nr = READ_ONCE(nd->nr);
-
- switch (target_nr) {
- case 0:
- target = NUMA_NO_NODE;
- goto out;
- case 1:
- index = 0;
- break;
- default:
- /*
- * If there are multiple target nodes, just select one
- * target node randomly.
- *
- * In addition, we can also use round-robin to select
- * target node, but we should introduce another variable
- * for node_demotion[] to record last selected target node,
- * that may cause cache ping-pong due to the changing of
- * last target node. Or introducing per-cpu data to avoid
- * caching issue, which seems more complicated. So selecting
- * target node randomly seems better until now.
- */
- index = get_random_int() % target_nr;
- break;
- }
-
- target = READ_ONCE(nd->nodes[index]);
-
-out:
- rcu_read_unlock();
- return target;
-}
-
-/* Disable reclaim-based migration. */
-static void __disable_all_migrate_targets(void)
-{
- int node, i;
-
- if (!node_demotion)
- return;
-
- for_each_online_node(node) {
- node_demotion[node].nr = 0;
- for (i = 0; i < DEMOTION_TARGET_NODES; i++)
- node_demotion[node].nodes[i] = NUMA_NO_NODE;
- }
-}
-
-static void disable_all_migrate_targets(void)
-{
- __disable_all_migrate_targets();
-
- /*
- * Ensure that the "disable" is visible across the system.
- * Readers will see either a combination of before+disable
- * state or disable+after. They will never see before and
- * after state together.
- *
- * The before+after state together might have cycles and
- * could cause readers to do things like loop until this
- * function finishes. This ensures they can only see a
- * single "bad" read and would, for instance, only loop
- * once.
- */
- synchronize_rcu();
-}
-
-/*
- * Find an automatic demotion target for 'node'.
- * Failing here is OK. It might just indicate
- * being at the end of a chain.
- */
-static int establish_migrate_target(int node, nodemask_t *used,
- int best_distance)
-{
- int migration_target, index, val;
- struct demotion_nodes *nd;
-
- if (!node_demotion)
- return NUMA_NO_NODE;
-
- nd = &node_demotion[node];
-
- migration_target = find_next_best_node(node, used);
- if (migration_target == NUMA_NO_NODE)
- return NUMA_NO_NODE;
-
- /*
- * If the node has been set a migration target node before,
- * which means it's the best distance between them. Still
- * check if this node can be demoted to other target nodes
- * if they have a same best distance.
- */
- if (best_distance != -1) {
- val = node_distance(node, migration_target);
- if (val > best_distance)
- goto out_clear;
- }
-
- index = nd->nr;
- if (WARN_ONCE(index >= DEMOTION_TARGET_NODES,
- "Exceeds maximum demotion target nodes\n"))
- goto out_clear;
-
- nd->nodes[index] = migration_target;
- nd->nr++;
-
- return migration_target;
-out_clear:
- node_clear(migration_target, *used);
- return NUMA_NO_NODE;
-}
-
-/*
- * When memory fills up on a node, memory contents can be
- * automatically migrated to another node instead of
- * discarded at reclaim.
- *
- * Establish a "migration path" which will start at nodes
- * with CPUs and will follow the priorities used to build the
- * page allocator zonelists.
- *
- * The difference here is that cycles must be avoided. If
- * node0 migrates to node1, then neither node1, nor anything
- * node1 migrates to can migrate to node0. Also one node can
- * be migrated to multiple nodes if the target nodes all have
- * a same best-distance against the source node.
- *
- * This function can run simultaneously with readers of
- * node_demotion[]. However, it can not run simultaneously
- * with itself. Exclusion is provided by memory hotplug events
- * being single-threaded.
- */
-static void __set_migration_target_nodes(void)
-{
- nodemask_t next_pass;
- nodemask_t this_pass;
- nodemask_t used_targets = NODE_MASK_NONE;
- int node, best_distance;
-
- /*
- * Avoid any oddities like cycles that could occur
- * from changes in the topology. This will leave
- * a momentary gap when migration is disabled.
- */
- disable_all_migrate_targets();
-
- /*
- * Allocations go close to CPUs, first. Assume that
- * the migration path starts at the nodes with CPUs.
- */
- next_pass = node_states[N_CPU];
-again:
- this_pass = next_pass;
- next_pass = NODE_MASK_NONE;
- /*
- * To avoid cycles in the migration "graph", ensure
- * that migration sources are not future targets by
- * setting them in 'used_targets'. Do this only
- * once per pass so that multiple source nodes can
- * share a target node.
- *
- * 'used_targets' will become unavailable in future
- * passes. This limits some opportunities for
- * multiple source nodes to share a destination.
- */
- nodes_or(used_targets, used_targets, this_pass);
-
- for_each_node_mask(node, this_pass) {
- best_distance = -1;
-
- /*
- * Try to set up the migration path for the node, and the target
- * migration nodes can be multiple, so doing a loop to find all
- * the target nodes if they all have a best node distance.
- */
- do {
- int target_node =
- establish_migrate_target(node, &used_targets,
- best_distance);
-
- if (target_node == NUMA_NO_NODE)
- break;
-
- if (best_distance == -1)
- best_distance = node_distance(node, target_node);
-
- /*
- * Visit targets from this pass in the next pass.
- * Eventually, every node will have been part of
- * a pass, and will become set in 'used_targets'.
- */
- node_set(target_node, next_pass);
- } while (1);
- }
- /*
- * 'next_pass' contains nodes which became migration
- * targets in this pass. Make additional passes until
- * no more migrations targets are available.
- */
- if (!nodes_empty(next_pass))
- goto again;
-}
-
-/*
- * For callers that do not hold get_online_mems() already.
- */
-void set_migration_target_nodes(void)
-{
- get_online_mems();
- __set_migration_target_nodes();
- put_online_mems();
-}
-
-/*
- * This leaves migrate-on-reclaim transiently disabled between
- * the MEM_GOING_OFFLINE and MEM_OFFLINE events. This runs
- * whether reclaim-based migration is enabled or not, which
- * ensures that the user can turn reclaim-based migration at
- * any time without needing to recalculate migration targets.
- *
- * These callbacks already hold get_online_mems(). That is why
- * __set_migration_target_nodes() can be used as opposed to
- * set_migration_target_nodes().
- */
-#ifdef CONFIG_MEMORY_HOTPLUG
-static int __meminit migrate_on_reclaim_callback(struct notifier_block *self,
- unsigned long action, void *_arg)
-{
- struct memory_notify *arg = _arg;
-
- /*
- * Only update the node migration order when a node is
- * changing status, like online->offline. This avoids
- * the overhead of synchronize_rcu() in most cases.
- */
- if (arg->status_change_nid < 0)
- return notifier_from_errno(0);
-
- switch (action) {
- case MEM_GOING_OFFLINE:
- /*
- * Make sure there are not transient states where
- * an offline node is a migration target. This
- * will leave migration disabled until the offline
- * completes and the MEM_OFFLINE case below runs.
- */
- disable_all_migrate_targets();
- break;
- case MEM_OFFLINE:
- case MEM_ONLINE:
- /*
- * Recalculate the target nodes once the node
- * reaches its final state (online or offline).
- */
- __set_migration_target_nodes();
- break;
- case MEM_CANCEL_OFFLINE:
- /*
- * MEM_GOING_OFFLINE disabled all the migration
- * targets. Reenable them.
- */
- __set_migration_target_nodes();
- break;
- case MEM_GOING_ONLINE:
- case MEM_CANCEL_ONLINE:
- break;
- }
-
- return notifier_from_errno(0);
-}
-#endif
-
-void __init migrate_on_reclaim_init(void)
-{
- node_demotion = kcalloc(nr_node_ids,
- sizeof(struct demotion_nodes),
- GFP_KERNEL);
- WARN_ON(!node_demotion);
-#ifdef CONFIG_MEMORY_HOTPLUG
- hotplug_memory_notifier(migrate_on_reclaim_callback, 100);
-#endif
- /*
- * At this point, all numa nodes with memory/CPus have their state
- * properly set, so we can build the demotion order now.
- * Let us hold the cpu_hotplug lock just, as we could possibily have
- * CPU hotplug events during boot.
- */
- cpus_read_lock();
- set_migration_target_nodes();
- cpus_read_unlock();
-}
#endif /* CONFIG_NUMA */
-
-
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 373d2730fcf2..35c6ff97cf29 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -28,7 +28,6 @@
#include <linux/mm_inline.h>
#include <linux/page_ext.h>
#include <linux/page_owner.h>
-#include <linux/migrate.h>
#include "internal.h"
@@ -2060,7 +2059,6 @@ static int vmstat_cpu_online(unsigned int cpu)
if (!node_state(cpu_to_node(cpu), N_CPU)) {
node_set_state(cpu_to_node(cpu), N_CPU);
- set_migration_target_nodes();
}
return 0;
@@ -2085,7 +2083,6 @@ static int vmstat_cpu_dead(unsigned int cpu)
return 0;
node_clear_state(node, N_CPU);
- set_migration_target_nodes();
return 0;
}
@@ -2118,7 +2115,6 @@ void __init init_mm_internals(void)
start_shepherd_timer();
#endif
- migrate_on_reclaim_init();
#ifdef CONFIG_PROC_FS
proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
--
2.37.1
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH v13 6/9] mm/demotion: Add pg_data_t member to track node memory tier details
2022-08-08 6:25 [PATCH v13 0/9] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
` (4 preceding siblings ...)
2022-08-08 6:25 ` [PATCH v13 5/9] mm/demotion: Build demotion targets based on explicit memory tiers Aneesh Kumar K.V
@ 2022-08-08 6:25 ` Aneesh Kumar K.V
2022-08-09 3:07 ` Huang, Ying
2022-08-09 5:21 ` Huang, Ying
2022-08-08 6:25 ` [PATCH v13 7/9] mm/demotion: Demote pages according to allocation fallback order Aneesh Kumar K.V
` (2 subsequent siblings)
8 siblings, 2 replies; 21+ messages in thread
From: Aneesh Kumar K.V @ 2022-08-08 6:25 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Wei Xu, Huang Ying, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss, Aneesh Kumar K.V
Also update different helpes to use NODE_DATA()->memtier. Since
node specific memtier can change based on the reassignment of
NUMA node to a different memory tiers, accessing NODE_DATA()->memtier
needs to happen under an rcu read lock or memory_tier_lock.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
include/linux/mmzone.h | 3 +++
mm/memory-tiers.c | 38 ++++++++++++++++++++++++++++++++------
2 files changed, 35 insertions(+), 6 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index aab70355d64f..353812495a70 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -928,6 +928,9 @@ typedef struct pglist_data {
/* Per-node vmstats */
struct per_cpu_nodestat __percpu *per_cpu_nodestats;
atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS];
+#ifdef CONFIG_NUMA
+ struct memory_tier __rcu *memtier;
+#endif
} pg_data_t;
#define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 02e514e87d5c..3778ac6a44a1 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -5,6 +5,7 @@
#include <linux/kobject.h>
#include <linux/memory.h>
#include <linux/random.h>
+#include <linux/mmzone.h>
#include <linux/memory-tiers.h>
#include "internal.h"
@@ -137,12 +138,18 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
static struct memory_tier *__node_get_memory_tier(int node)
{
- struct memory_dev_type *memtype;
+ pg_data_t *pgdat;
- memtype = node_memory_types[node];
- if (memtype && node_isset(node, memtype->nodes))
- return memtype->memtier;
- return NULL;
+ pgdat = NODE_DATA(node);
+ if (!pgdat)
+ return NULL;
+ /*
+ * Since we hold memory_tier_lock, we can avoid
+ * RCU read locks when accessing the details. No
+ * parallel updates are possible here.
+ */
+ return rcu_dereference_check(pgdat->memtier,
+ lockdep_is_held(&memory_tier_lock));
}
#ifdef CONFIG_MIGRATION
@@ -295,6 +302,8 @@ static struct memory_tier *set_node_memory_tier(int node)
{
struct memory_tier *memtier;
struct memory_dev_type *memtype;
+ pg_data_t *pgdat = NODE_DATA(node);
+
lockdep_assert_held_once(&memory_tier_lock);
@@ -307,6 +316,8 @@ static struct memory_tier *set_node_memory_tier(int node)
memtype = node_memory_types[node];
node_set(node, memtype->nodes);
memtier = find_create_memory_tier(memtype);
+ if (!IS_ERR(memtier))
+ rcu_assign_pointer(pgdat->memtier, memtier);
return memtier;
}
@@ -319,12 +330,25 @@ static void destroy_memory_tier(struct memory_tier *memtier)
static bool clear_node_memory_tier(int node)
{
bool cleared = false;
+ pg_data_t *pgdat;
struct memory_tier *memtier;
+ pgdat = NODE_DATA(node);
+ if (!pgdat)
+ return false;
+
+ /*
+ * Make sure that anybody looking at NODE_DATA who finds
+ * a valid memtier finds memory_dev_types with nodes still
+ * linked to the memtier. We achieve this by waiting for
+ * rcu read section to finish using synchronize_rcu.
+ */
memtier = __node_get_memory_tier(node);
if (memtier) {
struct memory_dev_type *memtype;
+ rcu_assign_pointer(pgdat->memtier, NULL);
+ synchronize_rcu();
memtype = node_memory_types[node];
node_clear(node, memtype->nodes);
if (nodes_empty(memtype->nodes)) {
@@ -422,8 +446,10 @@ static int __init memory_tier_init(void)
panic("%s() failed to register memory tier: %ld\n",
__func__, PTR_ERR(memtier));
- for_each_node_state(node, N_MEMORY)
+ for_each_node_state(node, N_MEMORY) {
__init_node_memory_type(node, default_dram_type);
+ rcu_assign_pointer(NODE_DATA(node)->memtier, memtier);
+ }
mutex_unlock(&memory_tier_lock);
#ifdef CONFIG_MIGRATION
--
2.37.1
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH v13 7/9] mm/demotion: Demote pages according to allocation fallback order
2022-08-08 6:25 [PATCH v13 0/9] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
` (5 preceding siblings ...)
2022-08-08 6:25 ` [PATCH v13 6/9] mm/demotion: Add pg_data_t member to track node memory tier details Aneesh Kumar K.V
@ 2022-08-08 6:25 ` Aneesh Kumar K.V
2022-08-08 6:26 ` [PATCH v13 8/9] mm/demotion: Update node_is_toptier to work with memory tiers Aneesh Kumar K.V
2022-08-08 6:26 ` [PATCH v13 9/9] lib/nodemask: Optimize node_random for nodemask with single NUMA node Aneesh Kumar K.V
8 siblings, 0 replies; 21+ messages in thread
From: Aneesh Kumar K.V @ 2022-08-08 6:25 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Wei Xu, Huang Ying, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss, Aneesh Kumar K . V
From: Jagdish Gediya <jvgediya.oss@gmail.com>
Currently, a higher tier node can only be demoted to selected nodes on the next
lower tier as defined by the demotion path. This strict demotion order does not
work in all use cases (e.g. some use cases may want to allow cross-socket
demotion to another node in the same demotion tier as a fallback when the
preferred demotion node is out of space). This demotion order is also
inconsistent with the page allocation fallback order when all the nodes in a
higher tier are out of space: The page allocation can fall back to any node from
any lower tier, whereas the demotion order doesn't allow that currently.
This patch adds support to get all the allowed demotion targets for a memory
tier. demote_page_list() function is now modified to utilize this allowed node
mask as the fallback allocation mask.
Signed-off-by: Jagdish Gediya <jvgediya.oss@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
include/linux/memory-tiers.h | 12 ++++++++
mm/memory-tiers.c | 51 +++++++++++++++++++++++++++++--
mm/vmscan.c | 58 ++++++++++++++++++++++++++----------
3 files changed, 103 insertions(+), 18 deletions(-)
diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index c8cd593fa2df..341ba8082e05 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -4,6 +4,7 @@
#include <linux/types.h>
#include <linux/nodemask.h>
+#include <linux/mmzone.h>
/*
* Each tier cover a abstrace distance chunk size of 128
*/
@@ -33,11 +34,17 @@ void init_node_memory_type(int node, struct memory_dev_type *default_type);
void clear_node_memory_type(int node, struct memory_dev_type *memtype);
#ifdef CONFIG_MIGRATION
int next_demotion_node(int node);
+void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets);
#else
static inline int next_demotion_node(int node)
{
return NUMA_NO_NODE;
}
+
+static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
+{
+ *targets = NODE_MASK_NONE;
+}
#endif
#else
@@ -57,5 +64,10 @@ static inline int next_demotion_node(int node)
{
return NUMA_NO_NODE;
}
+
+static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
+{
+ *targets = NODE_MASK_NONE;
+}
#endif /* CONFIG_NUMA */
#endif /* _LINUX_MEMORY_TIERS_H */
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 3778ac6a44a1..925d7168e825 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -5,7 +5,6 @@
#include <linux/kobject.h>
#include <linux/memory.h>
#include <linux/random.h>
-#include <linux/mmzone.h>
#include <linux/memory-tiers.h>
#include "internal.h"
@@ -21,6 +20,8 @@ struct memory_tier {
* adistance_start .. adistance_start + MEMTIER_CHUNK_SIZE
*/
int adistance_start;
+ /* All the nodes that are part of all the lower memory tiers. */
+ nodemask_t lower_tier_mask;
};
struct demotion_nodes {
@@ -153,6 +154,24 @@ static struct memory_tier *__node_get_memory_tier(int node)
}
#ifdef CONFIG_MIGRATION
+void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
+{
+ struct memory_tier *memtier;
+
+ /*
+ * pg_data_t.memtier updates includes a synchronize_rcu()
+ * which ensures that we either find NULL or a valid memtier
+ * in NODE_DATA. protect the access via rcu_read_lock();
+ */
+ rcu_read_lock();
+ memtier = rcu_dereference(pgdat->memtier);
+ if (memtier)
+ *targets = memtier->lower_tier_mask;
+ else
+ *targets = NODE_MASK_NONE;
+ rcu_read_unlock();
+}
+
/**
* next_demotion_node() - Get the next node in the demotion path
* @node: The starting node to lookup the next node
@@ -200,10 +219,19 @@ int next_demotion_node(int node)
static void disable_all_demotion_targets(void)
{
+ struct memory_tier *memtier;
int node;
- for_each_node_state(node, N_MEMORY)
+ for_each_node_state(node, N_MEMORY) {
node_demotion[node].preferred = NODE_MASK_NONE;
+ /*
+ * We are holding memory_tier_lock, it is safe
+ * to access pgda->memtier.
+ */
+ memtier = __node_get_memory_tier(node);
+ if (memtier)
+ memtier->lower_tier_mask = NODE_MASK_NONE;
+ }
/*
* Ensure that the "disable" is visible across the system.
* Readers will see either a combination of before+disable
@@ -235,7 +263,7 @@ static void establish_demotion_targets(void)
struct demotion_nodes *nd;
int target = NUMA_NO_NODE, node;
int distance, best_distance;
- nodemask_t tier_nodes;
+ nodemask_t tier_nodes, lower_tier;
lockdep_assert_held_once(&memory_tier_lock);
@@ -283,6 +311,23 @@ static void establish_demotion_targets(void)
}
} while (1);
}
+ /*
+ * Now build the lower_tier mask for each node collecting node mask from
+ * all memory tier below it. This allows us to fallback demotion page
+ * allocation to a set of nodes that is closer the above selected
+ * perferred node.
+ */
+ lower_tier = node_states[N_MEMORY];
+ list_for_each_entry(memtier, &memory_tiers, list) {
+ /*
+ * Keep removing current tier from lower_tier nodes,
+ * This will remove all nodes in current and above
+ * memory tier from the lower_tier mask.
+ */
+ tier_nodes = get_memtier_nodemask(memtier);
+ nodes_andnot(lower_tier, lower_tier, tier_nodes);
+ memtier->lower_tier_mask = lower_tier;
+ }
}
#else
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 5043b10ff71e..74b4ee8eca2b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1460,21 +1460,34 @@ static void folio_check_dirty_writeback(struct folio *folio,
mapping->a_ops->is_dirty_writeback(folio, dirty, writeback);
}
-static struct page *alloc_demote_page(struct page *page, unsigned long node)
+static struct page *alloc_demote_page(struct page *page, unsigned long private)
{
- struct migration_target_control mtc = {
- /*
- * Allocate from 'node', or fail quickly and quietly.
- * When this happens, 'page' will likely just be discarded
- * instead of migrated.
- */
- .gfp_mask = (GFP_HIGHUSER_MOVABLE & ~__GFP_RECLAIM) |
- __GFP_THISNODE | __GFP_NOWARN |
- __GFP_NOMEMALLOC | GFP_NOWAIT,
- .nid = node
- };
+ struct page *target_page;
+ nodemask_t *allowed_mask;
+ struct migration_target_control *mtc;
+
+ mtc = (struct migration_target_control *)private;
+
+ allowed_mask = mtc->nmask;
+ /*
+ * make sure we allocate from the target node first also trying to
+ * demote or reclaim pages from the target node via kswapd if we are
+ * low on free memory on target node. If we don't do this and if
+ * we have free memory on the slower(lower) memtier, we would start
+ * allocating pages from slower(lower) memory tiers without even forcing
+ * a demotion of cold pages from the target memtier. This can result
+ * in the kernel placing hot pages in slower(lower) memory tiers.
+ */
+ mtc->nmask = NULL;
+ mtc->gfp_mask |= __GFP_THISNODE;
+ target_page = alloc_migration_target(page, (unsigned long)mtc);
+ if (target_page)
+ return target_page;
- return alloc_migration_target(page, (unsigned long)&mtc);
+ mtc->gfp_mask &= ~__GFP_THISNODE;
+ mtc->nmask = allowed_mask;
+
+ return alloc_migration_target(page, (unsigned long)mtc);
}
/*
@@ -1487,6 +1500,19 @@ static unsigned int demote_page_list(struct list_head *demote_pages,
{
int target_nid = next_demotion_node(pgdat->node_id);
unsigned int nr_succeeded;
+ nodemask_t allowed_mask;
+
+ struct migration_target_control mtc = {
+ /*
+ * Allocate from 'node', or fail quickly and quietly.
+ * When this happens, 'page' will likely just be discarded
+ * instead of migrated.
+ */
+ .gfp_mask = (GFP_HIGHUSER_MOVABLE & ~__GFP_RECLAIM) | __GFP_NOWARN |
+ __GFP_NOMEMALLOC | GFP_NOWAIT,
+ .nid = target_nid,
+ .nmask = &allowed_mask
+ };
if (list_empty(demote_pages))
return 0;
@@ -1494,10 +1520,12 @@ static unsigned int demote_page_list(struct list_head *demote_pages,
if (target_nid == NUMA_NO_NODE)
return 0;
+ node_get_allowed_targets(pgdat, &allowed_mask);
+
/* Demotion ignores all cpuset and mempolicy settings */
migrate_pages(demote_pages, alloc_demote_page, NULL,
- target_nid, MIGRATE_ASYNC, MR_DEMOTION,
- &nr_succeeded);
+ (unsigned long)&mtc, MIGRATE_ASYNC, MR_DEMOTION,
+ &nr_succeeded);
if (current_is_kswapd())
__count_vm_events(PGDEMOTE_KSWAPD, nr_succeeded);
--
2.37.1
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH v13 8/9] mm/demotion: Update node_is_toptier to work with memory tiers
2022-08-08 6:25 [PATCH v13 0/9] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
` (6 preceding siblings ...)
2022-08-08 6:25 ` [PATCH v13 7/9] mm/demotion: Demote pages according to allocation fallback order Aneesh Kumar K.V
@ 2022-08-08 6:26 ` Aneesh Kumar K.V
2022-08-08 6:26 ` [PATCH v13 9/9] lib/nodemask: Optimize node_random for nodemask with single NUMA node Aneesh Kumar K.V
8 siblings, 0 replies; 21+ messages in thread
From: Aneesh Kumar K.V @ 2022-08-08 6:26 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Wei Xu, Huang Ying, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss, Aneesh Kumar K.V
With memory tiers support we can have memory only NUMA nodes
in the top tier from which we want to avoid promotion tracking NUMA
faults. Update node_is_toptier to work with memory tiers.
All NUMA nodes are by default top tier nodes. With lower memory
tiers added we consider all memory tiers above a memory tier having
CPU NUMA nodes as a top memory tier
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
include/linux/memory-tiers.h | 11 +++++++++
include/linux/node.h | 5 ----
mm/huge_memory.c | 1 +
mm/memory-tiers.c | 46 ++++++++++++++++++++++++++++++++++++
mm/migrate.c | 1 +
mm/mprotect.c | 1 +
6 files changed, 60 insertions(+), 5 deletions(-)
diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index 341ba8082e05..0bdd5955a5e2 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -35,6 +35,7 @@ void clear_node_memory_type(int node, struct memory_dev_type *memtype);
#ifdef CONFIG_MIGRATION
int next_demotion_node(int node);
void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets);
+bool node_is_toptier(int node);
#else
static inline int next_demotion_node(int node)
{
@@ -45,6 +46,11 @@ static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *target
{
*targets = NODE_MASK_NONE;
}
+
+static inline bool node_is_toptier(int node)
+{
+ return true;
+}
#endif
#else
@@ -69,5 +75,10 @@ static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *target
{
*targets = NODE_MASK_NONE;
}
+
+static inline bool node_is_toptier(int node)
+{
+ return true;
+}
#endif /* CONFIG_NUMA */
#endif /* _LINUX_MEMORY_TIERS_H */
diff --git a/include/linux/node.h b/include/linux/node.h
index 40d641a8bfb0..9ec680dd607f 100644
--- a/include/linux/node.h
+++ b/include/linux/node.h
@@ -185,9 +185,4 @@ static inline void register_hugetlbfs_with_node(node_registration_func_t reg,
#define to_node(device) container_of(device, struct node, dev)
-static inline bool node_is_toptier(int node)
-{
- return node_state(node, N_CPU);
-}
-
#endif /* _LINUX_NODE_H_ */
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 15965084816d..524498061e7c 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -36,6 +36,7 @@
#include <linux/numa.h>
#include <linux/page_owner.h>
#include <linux/sched/sysctl.h>
+#include <linux/memory-tiers.h>
#include <asm/tlb.h>
#include <asm/pgalloc.h>
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 925d7168e825..ea5c04f62170 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -33,6 +33,7 @@ static LIST_HEAD(memory_tiers);
static struct memory_dev_type *node_memory_types[MAX_NUMNODES];
static struct memory_dev_type *default_dram_type;
#ifdef CONFIG_MIGRATION
+static int top_tier_adistance;
/*
* node_demotion[] examples:
*
@@ -154,6 +155,31 @@ static struct memory_tier *__node_get_memory_tier(int node)
}
#ifdef CONFIG_MIGRATION
+bool node_is_toptier(int node)
+{
+ bool toptier;
+ pg_data_t *pgdat;
+ struct memory_tier *memtier;
+
+ pgdat = NODE_DATA(node);
+ if (!pgdat)
+ return false;
+
+ rcu_read_lock();
+ memtier = rcu_dereference(pgdat->memtier);
+ if (!memtier) {
+ toptier = true;
+ goto out;
+ }
+ if (memtier->adistance_start < top_tier_adistance)
+ toptier = true;
+ else
+ toptier = false;
+out:
+ rcu_read_unlock();
+ return toptier;
+}
+
void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
{
struct memory_tier *memtier;
@@ -311,6 +337,26 @@ static void establish_demotion_targets(void)
}
} while (1);
}
+ /*
+ * Promotion is allowed from a memory tier to higher
+ * memory tier only if the memory tier doesn't include
+ * compute. We want to skip promotion from a memory tier,
+ * if any node that is part of the memory tier have CPUs.
+ * Once we detect such a memory tier, we consider that tier
+ * as top tiper from which promotion is not allowed.
+ */
+ list_for_each_entry_reverse(memtier, &memory_tiers, list) {
+ tier_nodes = get_memtier_nodemask(memtier);
+ nodes_and(tier_nodes, node_states[N_CPU], tier_nodes);
+ if (!nodes_empty(tier_nodes)) {
+ /*
+ * abstract distance below the max value of this memtier
+ * is considered toptier.
+ */
+ top_tier_adistance = memtier->adistance_start + MEMTIER_CHUNK_SIZE;
+ break;
+ }
+ }
/*
* Now build the lower_tier mask for each node collecting node mask from
* all memory tier below it. This allows us to fallback demotion page
diff --git a/mm/migrate.c b/mm/migrate.c
index 45290ddd3806..e7f3f52596c1 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -50,6 +50,7 @@
#include <linux/memory.h>
#include <linux/random.h>
#include <linux/sched/sysctl.h>
+#include <linux/memory-tiers.h>
#include <asm/tlbflush.h>
diff --git a/mm/mprotect.c b/mm/mprotect.c
index ba5592655ee3..92a2fc0fa88b 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -31,6 +31,7 @@
#include <linux/pgtable.h>
#include <linux/sched/sysctl.h>
#include <linux/userfaultfd_k.h>
+#include <linux/memory-tiers.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
--
2.37.1
^ permalink raw reply related [flat|nested] 21+ messages in thread
* [PATCH v13 9/9] lib/nodemask: Optimize node_random for nodemask with single NUMA node
2022-08-08 6:25 [PATCH v13 0/9] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
` (7 preceding siblings ...)
2022-08-08 6:26 ` [PATCH v13 8/9] mm/demotion: Update node_is_toptier to work with memory tiers Aneesh Kumar K.V
@ 2022-08-08 6:26 ` Aneesh Kumar K.V
2022-08-09 3:13 ` Huang, Ying
8 siblings, 1 reply; 21+ messages in thread
From: Aneesh Kumar K.V @ 2022-08-08 6:26 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Wei Xu, Huang Ying, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss, Aneesh Kumar K.V
The most common case for certain node_random usage (demotion nodemask) is with
nodemask weight 1. We can avoid calling get_random_init() in that case and
always return the only node set in the nodemask.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
lib/nodemask.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/lib/nodemask.c b/lib/nodemask.c
index e22647f5181b..c91a6b0404a5 100644
--- a/lib/nodemask.c
+++ b/lib/nodemask.c
@@ -20,12 +20,21 @@ EXPORT_SYMBOL(__next_node_in);
*/
int node_random(const nodemask_t *maskp)
{
- int w, bit = NUMA_NO_NODE;
+ int w, bit;
w = nodes_weight(*maskp);
- if (w)
+ switch (w) {
+ case 0:
+ bit = NUMA_NO_NODE;
+ break;
+ case 1:
+ bit = __first_node(maskp);
+ break;
+ default:
bit = bitmap_ord_to_pos(maskp->bits,
- get_random_int() % w, MAX_NUMNODES);
+ get_random_int() % w, MAX_NUMNODES);
+ break;
+ }
return bit;
}
#endif
--
2.37.1
^ permalink raw reply related [flat|nested] 21+ messages in thread
* Re: [PATCH v13 1/9] mm/demotion: Add support for explicit memory tiers
2022-08-08 6:25 ` [PATCH v13 1/9] mm/demotion: Add support for explicit memory tiers Aneesh Kumar K.V
@ 2022-08-09 1:58 ` Huang, Ying
2022-08-09 5:34 ` Aneesh Kumar K V
0 siblings, 1 reply; 21+ messages in thread
From: Huang, Ying @ 2022-08-09 1:58 UTC (permalink / raw)
To: Aneesh Kumar K.V
Cc: linux-mm, akpm, Wei Xu, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
> In the current kernel, memory tiers are defined implicitly via a demotion path
> relationship between NUMA nodes, which is created during the kernel
> initialization and updated when a NUMA node is hot-added or hot-removed. The
> current implementation puts all nodes with CPU into the highest tier, and builds
> the tier hierarchy by establishing the per-node demotion targets based on the
> distances between nodes.
>
> This current memory tier kernel implementation needs to be improved for several
> important use cases,
>
> The current tier initialization code always initializes each memory-only NUMA
> node into a lower tier. But a memory-only NUMA node may have a high performance
> memory device (e.g. a DRAM-backed memory-only node on a virtual machine) that
> should be put into a higher tier.
>
> The current tier hierarchy always puts CPU nodes into the top tier. But on a
> system with HBM or GPU devices, the memory-only NUMA nodes mapping these devices
> should be in the top tier, and DRAM nodes with CPUs are better to be placed into
> the next lower tier.
>
> With current kernel higher tier node can only be demoted to nodes with shortest
> distance on the next lower tier as defined by the demotion path, not any other
> node from any lower tier. This strict, demotion order does not work in all use
> cases (e.g. some use cases may want to allow cross-socket demotion to another
> node in the same demotion tier as a fallback when the preferred demotion node is
> out of space), This demotion order is also inconsistent with the page allocation
> fallback order when all the nodes in a higher tier are out of space: The page
> allocation can fall back to any node from any lower tier, whereas the demotion
> order doesn't allow that.
>
> This patch series address the above by defining memory tiers explicitly.
>
> Linux kernel presents memory devices as NUMA nodes and each memory device is of
> a specific type. The memory type of a device is represented by its abstract
> distance. A memory tier corresponds to a range of abstract distance. This allows
> for classifying memory devices with a specific performance range into a memory
> tier.
>
> This patch configures the range/chunk size to be 128. The default DRAM abstract
> distance is 512. We can have 4 memory tiers below the default DRAM with abstract
> distance range 0 - 127, 127 - 255, 256- 383, 384 - 511. Faster memory devices
> can be placed in these faster(higher) memory tiers. Slower memory devices like
> persistent memory will have abstract distance higher than the default DRAM
> level.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
> include/linux/memory-tiers.h | 15 +++++
> mm/Makefile | 1 +
> mm/memory-tiers.c | 107 +++++++++++++++++++++++++++++++++++
> 3 files changed, 123 insertions(+)
> create mode 100644 include/linux/memory-tiers.h
> create mode 100644 mm/memory-tiers.c
>
> diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
> new file mode 100644
> index 000000000000..bc7c1b799bef
> --- /dev/null
> +++ b/include/linux/memory-tiers.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _LINUX_MEMORY_TIERS_H
> +#define _LINUX_MEMORY_TIERS_H
> +
> +/*
> + * Each tier cover a abstrace distance chunk size of 128
> + */
> +#define MEMTIER_CHUNK_BITS 7
> +#define MEMTIER_CHUNK_SIZE (1 << MEMTIER_CHUNK_BITS)
> +/*
> + * Smaller abstract distance value imply faster(higher) memory tiers.
> + */
> +#define MEMTIER_ADISTANCE_DRAM (4 * MEMTIER_CHUNK_SIZE)
> +
> +#endif /* _LINUX_MEMORY_TIERS_H */
> diff --git a/mm/Makefile b/mm/Makefile
> index 6f9ffa968a1a..d30acebc2164 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -92,6 +92,7 @@ obj-$(CONFIG_KFENCE) += kfence/
> obj-$(CONFIG_FAILSLAB) += failslab.o
> obj-$(CONFIG_MEMTEST) += memtest.o
> obj-$(CONFIG_MIGRATION) += migrate.o
> +obj-$(CONFIG_NUMA) += memory-tiers.o
> obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o
> obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
> obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
> new file mode 100644
> index 000000000000..78b311d9bde9
> --- /dev/null
> +++ b/mm/memory-tiers.c
> @@ -0,0 +1,107 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/types.h>
> +#include <linux/nodemask.h>
> +#include <linux/slab.h>
> +#include <linux/lockdep.h>
> +#include <linux/memory-tiers.h>
> +
> +struct memory_tier {
> + /* hierarchy of memory tiers */
> + struct list_head list;
> + /* list of all memory types part of this tier */
> + struct list_head memory_types;
> + /*
> + * start value of abstract distance. memory tier maps
> + * an abstract distance range,
> + * adistance_start .. adistance_start + MEMTIER_CHUNK_SIZE
> + */
> + int adistance_start;
> +};
> +
> +struct memory_dev_type {
> + /* list of memory types that are part of same tier as this type */
> + struct list_head tier_sibiling;
> + /* abstract distance for this specific memory type */
> + int adistance;
> + /* Nodes of same abstract distance */
> + nodemask_t nodes;
> + struct memory_tier *memtier;
> +};
> +
> +static DEFINE_MUTEX(memory_tier_lock);
> +static LIST_HEAD(memory_tiers);
> +static struct memory_dev_type *node_memory_types[MAX_NUMNODES];
> +/*
> + * For now let's have 4 memory tier below default DRAM tier.
> + */
> +static struct memory_dev_type default_dram_type = {
> + .adistance = MEMTIER_ADISTANCE_DRAM,
> + .tier_sibiling = LIST_HEAD_INIT(default_dram_type.tier_sibiling),
> +};
> +
> +static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype)
> +{
> + bool found_slot = false;
> + struct memory_tier *memtier, *new_memtier;
> + int adistance = memtype->adistance;
> + unsigned int memtier_adistance_chunk_size = MEMTIER_CHUNK_SIZE;
> +
> + lockdep_assert_held_once(&memory_tier_lock);
> +
> + /*
> + * If the memtype is already part of a memory tier,
> + * just return that.
> + */
> + if (memtype->memtier)
> + return memtype->memtier;
> +
> + adistance = round_down(adistance, memtier_adistance_chunk_size);
> + list_for_each_entry(memtier, &memory_tiers, list) {
> + if (adistance == memtier->adistance_start) {
> + memtype->memtier = memtier;
> + list_add(&memtype->tier_sibiling, &memtier->memory_types);
> + return memtier;
> + } else if (adistance < memtier->adistance_start) {
> + found_slot = true;
> + break;
> + }
> + }
> +
> + new_memtier = kmalloc(sizeof(struct memory_tier), GFP_KERNEL);
> + if (!new_memtier)
> + return ERR_PTR(-ENOMEM);
> +
> + new_memtier->adistance_start = adistance;
> + INIT_LIST_HEAD(&new_memtier->list);
> + INIT_LIST_HEAD(&new_memtier->memory_types);
> + if (found_slot)
> + list_add_tail(&new_memtier->list, &memtier->list);
> + else
> + list_add_tail(&new_memtier->list, &memory_tiers);
> + memtype->memtier = new_memtier;
> + list_add(&memtype->tier_sibiling, &new_memtier->memory_types);
> + return new_memtier;
> +}
> +
> +static int __init memory_tier_init(void)
> +{
> + int node;
> + struct memory_tier *memtier;
> +
> + mutex_lock(&memory_tier_lock);
> + /* CPU only nodes are not part of memory tiers. */
> + default_dram_type.nodes = node_states[N_MEMORY];
> +
> + memtier = find_create_memory_tier(&default_dram_type);
> + if (IS_ERR(memtier))
> + panic("%s() failed to register memory tier: %ld\n",
> + __func__, PTR_ERR(memtier));
> +
> + for_each_node_state(node, N_MEMORY)
> + node_memory_types[node] = &default_dram_type;
Although not absolutely necessary, it seems better to set
node_memory_types[] before adding nodes to the memory type and adding
the memory type to the memory tier.
Best Regards,
Huang, Ying
> +
> + mutex_unlock(&memory_tier_lock);
> +
> + return 0;
> +}
> +subsys_initcall(memory_tier_init);
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH v13 4/9] mm/demotion/dax/kmem: Set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE
2022-08-08 6:25 ` [PATCH v13 4/9] mm/demotion/dax/kmem: Set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE Aneesh Kumar K.V
@ 2022-08-09 3:04 ` Huang, Ying
2022-08-09 5:33 ` Aneesh Kumar K V
0 siblings, 1 reply; 21+ messages in thread
From: Huang, Ying @ 2022-08-09 3:04 UTC (permalink / raw)
To: Aneesh Kumar K.V
Cc: linux-mm, akpm, Wei Xu, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
> By default, all nodes are assigned to the default memory tier which
> is the memory tier designated for nodes with DRAM
>
> Set dax kmem device node's tier to slower memory tier by assigning
> abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE. Low-level drivers
> like papr_scm or ACPI NFIT can initialize memory device type to a
> more accurate value based on device tree details or HMAT.
I don't know how ACPI NFIT can help here. Can you teach me?
Per my understanding, we may use the information provided by ACPI SLIT
or HMAT (or device tree via papr_scm) to create memory types. Before
that is implemented, we just create a memory type with default abstract
distance.
> If the
> kernel doesn't find the memory type initialized, a default slower
> memory type is assigned by the kmem driver.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
> drivers/dax/kmem.c | 40 ++++++++++++++++++-
> include/linux/memory-tiers.h | 26 ++++++++++++-
> mm/memory-tiers.c | 74 +++++++++++++++++++++++++-----------
> 3 files changed, 115 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
> index a37622060fff..b5cb03307af8 100644
> --- a/drivers/dax/kmem.c
> +++ b/drivers/dax/kmem.c
> @@ -11,9 +11,17 @@
> #include <linux/fs.h>
> #include <linux/mm.h>
> #include <linux/mman.h>
> +#include <linux/memory-tiers.h>
> #include "dax-private.h"
> #include "bus.h"
>
> +/*
> + * Default abstract distance assigned to the NUMA node onlined
> + * by DAX/kmem if the low level platform driver didn't initialize
> + * one for this NUMA node.
> + */
We have 2 choices here.
1. The low level drivers create memory types and set
node_memory_types[]. We need a mechanism to coordinate among multiple
drivers. On x86, we have ACPI SLIT, HMAT. And we have platform
independent CXL defined CDAT.
2. The high level driver (such as dax/kmem.c) coordinate among multiple
low level drivers. For example, it may query CXL CDAT firstly, and use
a notifier chain to query platform drivers with priority.
Personally, I prefer choice 2. We can discuss this later. But can we
make the comments more general to avoid to make decision now?
> +#define MEMTIER_DEFAULT_DAX_ADISTANCE (MEMTIER_ADISTANCE_DRAM * 2)
> +
> /* Memory resource name used for add_memory_driver_managed(). */
> static const char *kmem_name;
> /* Set if any memory will remain added when the driver will be unloaded. */
> @@ -41,6 +49,7 @@ struct dax_kmem_data {
> struct resource *res[];
> };
>
> +static struct memory_dev_type *dax_slowmem_type;
I don't think "slowmem" make much sense here. There may be even slower
memory. Just dax_mem_type or dax_kmem_type should be OK?
> static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
> {
> struct device *dev = &dev_dax->dev;
> @@ -62,6 +71,8 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
> return -EINVAL;
> }
>
> + init_node_memory_type(numa_node, dax_slowmem_type);
> +
I don't find error handling in this function. Per my understanding, if
memory hot-add fails, we need to call clear_node_memory_type().
> for (i = 0; i < dev_dax->nr_range; i++) {
> struct range range;
>
> @@ -162,6 +173,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
> static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
> {
> int i, success = 0;
> + int node = dev_dax->target_node;
> struct device *dev = &dev_dax->dev;
> struct dax_kmem_data *data = dev_get_drvdata(dev);
>
> @@ -198,6 +210,14 @@ static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
> kfree(data->res_name);
> kfree(data);
> dev_set_drvdata(dev, NULL);
> + /*
> + * Clear the memtype association on successful unplug.
> + * If not, we have memory blocks left which can be
> + * offlined/onlined later. We need to keep memory_dev_type
> + * for that. This implies this reference will be around
> + * till next reboot.
> + */
> + clear_node_memory_type(node, dax_slowmem_type);
> }
> }
> #else
> @@ -228,9 +248,27 @@ static int __init dax_kmem_init(void)
> if (!kmem_name)
> return -ENOMEM;
>
> + dax_slowmem_type = kmalloc(sizeof(*dax_slowmem_type), GFP_KERNEL);
> + if (!dax_slowmem_type) {
> + rc = -ENOMEM;
> + goto kmem_name_free;
> + }
> + dax_slowmem_type->adistance = MEMTIER_DEFAULT_DAX_ADISTANCE;
> + INIT_LIST_HEAD(&dax_slowmem_type->tier_sibiling);
> + dax_slowmem_type->nodes = NODE_MASK_NONE;
> + dax_slowmem_type->memtier = NULL;
> + kref_init(&dax_slowmem_type->kref);
> +
Here we initialize the kref to 1. So in dax_kmem_exit() we should drop
the last reference, otherwise we cannot free the memory type?
> rc = dax_driver_register(&device_dax_kmem_driver);
> if (rc)
> - kfree_const(kmem_name);
> + goto error_out;
> +
> + return rc;
> +
> +error_out:
> + kfree(dax_slowmem_type);
> +kmem_name_free:
> + kfree_const(kmem_name);
> return rc;
> }
>
> diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
> index cc89876899a6..7bf6f47d581a 100644
> --- a/include/linux/memory-tiers.h
> +++ b/include/linux/memory-tiers.h
> @@ -2,6 +2,8 @@
> #ifndef _LINUX_MEMORY_TIERS_H
> #define _LINUX_MEMORY_TIERS_H
>
> +#include <linux/types.h>
> +#include <linux/nodemask.h>
> /*
> * Each tier cover a abstrace distance chunk size of 128
> */
> @@ -13,12 +15,34 @@
> #define MEMTIER_ADISTANCE_DRAM (4 * MEMTIER_CHUNK_SIZE)
> #define MEMTIER_HOTPLUG_PRIO 100
>
> +struct memory_tier;
> +struct memory_dev_type {
> + /* list of memory types that are part of same tier as this type */
> + struct list_head tier_sibiling;
> + /* abstract distance for this specific memory type */
> + int adistance;
> + /* Nodes of same abstract distance */
> + nodemask_t nodes;
> + struct kref kref;
> + struct memory_tier *memtier;
> +};
> +
> #ifdef CONFIG_NUMA
> -#include <linux/types.h>
> extern bool numa_demotion_enabled;
> +void init_node_memory_type(int node, struct memory_dev_type *default_type);
> +void clear_node_memory_type(int node, struct memory_dev_type *memtype);
>
> #else
>
> #define numa_demotion_enabled false
> +static inline void init_node_memory_type(int node, struct memory_dev_type *default_type)
> +{
> +
> +}
> +
> +static inline void clear_node_memory_type(int node, struct memory_dev_type *memtype)
> +{
> +
> +}
> #endif /* CONFIG_NUMA */
> #endif /* _LINUX_MEMORY_TIERS_H */
> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
> index 2caa5ab446b8..e07dffb67567 100644
> --- a/mm/memory-tiers.c
> +++ b/mm/memory-tiers.c
> @@ -1,6 +1,4 @@
> // SPDX-License-Identifier: GPL-2.0
> -#include <linux/types.h>
> -#include <linux/nodemask.h>
> #include <linux/slab.h>
> #include <linux/lockdep.h>
> #include <linux/sysfs.h>
> @@ -21,26 +19,10 @@ struct memory_tier {
> int adistance_start;
> };
>
> -struct memory_dev_type {
> - /* list of memory types that are part of same tier as this type */
> - struct list_head tier_sibiling;
> - /* abstract distance for this specific memory type */
> - int adistance;
> - /* Nodes of same abstract distance */
> - nodemask_t nodes;
> - struct memory_tier *memtier;
> -};
> -
> static DEFINE_MUTEX(memory_tier_lock);
> static LIST_HEAD(memory_tiers);
> static struct memory_dev_type *node_memory_types[MAX_NUMNODES];
> -/*
> - * For now let's have 4 memory tier below default DRAM tier.
> - */
> -static struct memory_dev_type default_dram_type = {
> - .adistance = MEMTIER_ADISTANCE_DRAM,
> - .tier_sibiling = LIST_HEAD_INIT(default_dram_type.tier_sibiling),
> -};
> +static struct memory_dev_type *default_dram_type;
>
> static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype)
> {
> @@ -96,6 +78,14 @@ static struct memory_tier *__node_get_memory_tier(int node)
> return NULL;
> }
>
> +static inline void __init_node_memory_type(int node, struct memory_dev_type *default_type)
> +{
> + if (!node_memory_types[node]) {
> + node_memory_types[node] = default_type;
> + kref_get(&default_type->kref);
> + }
> +}
> +
> static struct memory_tier *set_node_memory_tier(int node)
> {
> struct memory_tier *memtier;
> @@ -107,7 +97,7 @@ static struct memory_tier *set_node_memory_tier(int node)
> return ERR_PTR(-EINVAL);
>
> if (!node_memory_types[node])
> - node_memory_types[node] = &default_dram_type;
> + __init_node_memory_type(node, default_dram_type);
>
> memtype = node_memory_types[node];
> node_set(node, memtype->nodes);
> @@ -143,6 +133,34 @@ static bool clear_node_memory_tier(int node)
> return cleared;
> }
>
> +void init_node_memory_type(int node, struct memory_dev_type *default_type)
> +{
> +
> + mutex_lock(&memory_tier_lock);
> + __init_node_memory_type(node, default_type);
> + mutex_unlock(&memory_tier_lock);
> +}
> +EXPORT_SYMBOL_GPL(init_node_memory_type);
> +
> +static void release_memtype(struct kref *kref)
> +{
> + struct memory_dev_type *memtype;
> +
> + memtype = container_of(kref, struct memory_dev_type, kref);
> + kfree(memtype);
> +}
> +
> +void clear_node_memory_type(int node, struct memory_dev_type *memtype)
> +{
> + mutex_lock(&memory_tier_lock);
> + if (node_memory_types[node] == memtype) {
> + node_memory_types[node] = NULL;
> + kref_put(&memtype->kref, release_memtype);
> + }
> + mutex_unlock(&memory_tier_lock);
> +}
> +EXPORT_SYMBOL_GPL(clear_node_memory_type);
> +
> static int __meminit memtier_hotplug_callback(struct notifier_block *self,
> unsigned long action, void *_arg)
> {
> @@ -176,17 +194,27 @@ static int __init memory_tier_init(void)
> int node;
> struct memory_tier *memtier;
>
> + default_dram_type = kmalloc(sizeof(*default_dram_type), GFP_KERNEL);
> + if (!default_dram_type)
> + panic("%s() failed to allocate default DRAM tier\n", __func__);
> +
> mutex_lock(&memory_tier_lock);
> +
> + /* For now let's have 4 memory tier below default DRAM tier. */
> + default_dram_type->adistance = MEMTIER_ADISTANCE_DRAM;
> + INIT_LIST_HEAD(&default_dram_type->tier_sibiling);
> + default_dram_type->memtier = NULL;
> + kref_init(&default_dram_type->kref);
It appears that we can define a function to initialize a memory type.
> /* CPU only nodes are not part of memory tiers. */
> - default_dram_type.nodes = node_states[N_MEMORY];
> + default_dram_type->nodes = node_states[N_MEMORY];
>
> - memtier = find_create_memory_tier(&default_dram_type);
> + memtier = find_create_memory_tier(default_dram_type);
> if (IS_ERR(memtier))
> panic("%s() failed to register memory tier: %ld\n",
> __func__, PTR_ERR(memtier));
>
> for_each_node_state(node, N_MEMORY)
> - node_memory_types[node] = &default_dram_type;
> + __init_node_memory_type(node, default_dram_type);
>
> mutex_unlock(&memory_tier_lock);
Best Regards,
Huang, Ying
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH v13 6/9] mm/demotion: Add pg_data_t member to track node memory tier details
2022-08-08 6:25 ` [PATCH v13 6/9] mm/demotion: Add pg_data_t member to track node memory tier details Aneesh Kumar K.V
@ 2022-08-09 3:07 ` Huang, Ying
2022-08-09 5:21 ` Huang, Ying
1 sibling, 0 replies; 21+ messages in thread
From: Huang, Ying @ 2022-08-09 3:07 UTC (permalink / raw)
To: Aneesh Kumar K.V
Cc: linux-mm, akpm, Wei Xu, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
> Also update different helpes to use NODE_DATA()->memtier. Since
> node specific memtier can change based on the reassignment of
> NUMA node to a different memory tiers, accessing NODE_DATA()->memtier
> needs to happen under an rcu read lock or memory_tier_lock.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
> include/linux/mmzone.h | 3 +++
> mm/memory-tiers.c | 38 ++++++++++++++++++++++++++++++++------
> 2 files changed, 35 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index aab70355d64f..353812495a70 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -928,6 +928,9 @@ typedef struct pglist_data {
> /* Per-node vmstats */
> struct per_cpu_nodestat __percpu *per_cpu_nodestats;
> atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS];
> +#ifdef CONFIG_NUMA
> + struct memory_tier __rcu *memtier;
> +#endif
> } pg_data_t;
>
> #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
> index 02e514e87d5c..3778ac6a44a1 100644
> --- a/mm/memory-tiers.c
> +++ b/mm/memory-tiers.c
> @@ -5,6 +5,7 @@
> #include <linux/kobject.h>
> #include <linux/memory.h>
> #include <linux/random.h>
> +#include <linux/mmzone.h>
> #include <linux/memory-tiers.h>
>
> #include "internal.h"
> @@ -137,12 +138,18 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
>
> static struct memory_tier *__node_get_memory_tier(int node)
> {
> - struct memory_dev_type *memtype;
> + pg_data_t *pgdat;
>
> - memtype = node_memory_types[node];
> - if (memtype && node_isset(node, memtype->nodes))
> - return memtype->memtier;
> - return NULL;
> + pgdat = NODE_DATA(node);
> + if (!pgdat)
> + return NULL;
> + /*
> + * Since we hold memory_tier_lock, we can avoid
> + * RCU read locks when accessing the details. No
> + * parallel updates are possible here.
> + */
> + return rcu_dereference_check(pgdat->memtier,
> + lockdep_is_held(&memory_tier_lock));
> }
>
> #ifdef CONFIG_MIGRATION
> @@ -295,6 +302,8 @@ static struct memory_tier *set_node_memory_tier(int node)
> {
> struct memory_tier *memtier;
> struct memory_dev_type *memtype;
> + pg_data_t *pgdat = NODE_DATA(node);
> +
>
> lockdep_assert_held_once(&memory_tier_lock);
>
> @@ -307,6 +316,8 @@ static struct memory_tier *set_node_memory_tier(int node)
> memtype = node_memory_types[node];
> node_set(node, memtype->nodes);
> memtier = find_create_memory_tier(memtype);
> + if (!IS_ERR(memtier))
> + rcu_assign_pointer(pgdat->memtier, memtier);
> return memtier;
> }
>
> @@ -319,12 +330,25 @@ static void destroy_memory_tier(struct memory_tier *memtier)
> static bool clear_node_memory_tier(int node)
> {
> bool cleared = false;
> + pg_data_t *pgdat;
> struct memory_tier *memtier;
>
> + pgdat = NODE_DATA(node);
> + if (!pgdat)
> + return false;
> +
> + /*
> + * Make sure that anybody looking at NODE_DATA who finds
> + * a valid memtier finds memory_dev_types with nodes still
> + * linked to the memtier. We achieve this by waiting for
> + * rcu read section to finish using synchronize_rcu.
> + */
The synchronize_rcu() is also needed because we may free the memory
tier.
Best Regards,
Huang, Ying
> memtier = __node_get_memory_tier(node);
> if (memtier) {
> struct memory_dev_type *memtype;
>
> + rcu_assign_pointer(pgdat->memtier, NULL);
> + synchronize_rcu();
> memtype = node_memory_types[node];
> node_clear(node, memtype->nodes);
> if (nodes_empty(memtype->nodes)) {
> @@ -422,8 +446,10 @@ static int __init memory_tier_init(void)
> panic("%s() failed to register memory tier: %ld\n",
> __func__, PTR_ERR(memtier));
>
> - for_each_node_state(node, N_MEMORY)
> + for_each_node_state(node, N_MEMORY) {
> __init_node_memory_type(node, default_dram_type);
> + rcu_assign_pointer(NODE_DATA(node)->memtier, memtier);
> + }
>
> mutex_unlock(&memory_tier_lock);
> #ifdef CONFIG_MIGRATION
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH v13 9/9] lib/nodemask: Optimize node_random for nodemask with single NUMA node
2022-08-08 6:26 ` [PATCH v13 9/9] lib/nodemask: Optimize node_random for nodemask with single NUMA node Aneesh Kumar K.V
@ 2022-08-09 3:13 ` Huang, Ying
2022-08-09 5:43 ` Aneesh Kumar K V
0 siblings, 1 reply; 21+ messages in thread
From: Huang, Ying @ 2022-08-09 3:13 UTC (permalink / raw)
To: Aneesh Kumar K.V
Cc: linux-mm, akpm, Wei Xu, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
> The most common case for certain node_random usage (demotion nodemask) is with
> nodemask weight 1. We can avoid calling get_random_init() in that case and
> always return the only node set in the nodemask.
I think that this patch can sit between [5/9] and [6/9], just after it
is used.
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
> lib/nodemask.c | 15 ++++++++++++---
> 1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/lib/nodemask.c b/lib/nodemask.c
> index e22647f5181b..c91a6b0404a5 100644
> --- a/lib/nodemask.c
> +++ b/lib/nodemask.c
> @@ -20,12 +20,21 @@ EXPORT_SYMBOL(__next_node_in);
> */
> int node_random(const nodemask_t *maskp)
> {
> - int w, bit = NUMA_NO_NODE;
> + int w, bit;
>
> w = nodes_weight(*maskp);
> - if (w)
> + switch (w) {
> + case 0:
> + bit = NUMA_NO_NODE;
> + break;
> + case 1:
> + bit = __first_node(maskp);
Per my understanding, first_node() is the formal API and we should use
that? Just like we use nodes_weight() instead of __nodes_weight().
Best Regards,
Huang, Ying
> + break;
> + default:
> bit = bitmap_ord_to_pos(maskp->bits,
> - get_random_int() % w, MAX_NUMNODES);
> + get_random_int() % w, MAX_NUMNODES);
> + break;
> + }
> return bit;
> }
> #endif
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH v13 6/9] mm/demotion: Add pg_data_t member to track node memory tier details
2022-08-08 6:25 ` [PATCH v13 6/9] mm/demotion: Add pg_data_t member to track node memory tier details Aneesh Kumar K.V
2022-08-09 3:07 ` Huang, Ying
@ 2022-08-09 5:21 ` Huang, Ying
2022-08-09 5:41 ` Aneesh Kumar K V
1 sibling, 1 reply; 21+ messages in thread
From: Huang, Ying @ 2022-08-09 5:21 UTC (permalink / raw)
To: Aneesh Kumar K.V
Cc: linux-mm, akpm, Wei Xu, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
> Also update different helpes to use NODE_DATA()->memtier. Since
> node specific memtier can change based on the reassignment of
> NUMA node to a different memory tiers, accessing NODE_DATA()->memtier
> needs to happen under an rcu read lock or memory_tier_lock.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
> include/linux/mmzone.h | 3 +++
> mm/memory-tiers.c | 38 ++++++++++++++++++++++++++++++++------
> 2 files changed, 35 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index aab70355d64f..353812495a70 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -928,6 +928,9 @@ typedef struct pglist_data {
> /* Per-node vmstats */
> struct per_cpu_nodestat __percpu *per_cpu_nodestats;
> atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS];
> +#ifdef CONFIG_NUMA
> + struct memory_tier __rcu *memtier;
> +#endif
> } pg_data_t;
>
> #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
> index 02e514e87d5c..3778ac6a44a1 100644
> --- a/mm/memory-tiers.c
> +++ b/mm/memory-tiers.c
> @@ -5,6 +5,7 @@
> #include <linux/kobject.h>
> #include <linux/memory.h>
> #include <linux/random.h>
> +#include <linux/mmzone.h>
> #include <linux/memory-tiers.h>
>
> #include "internal.h"
> @@ -137,12 +138,18 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
>
> static struct memory_tier *__node_get_memory_tier(int node)
> {
> - struct memory_dev_type *memtype;
> + pg_data_t *pgdat;
>
> - memtype = node_memory_types[node];
> - if (memtype && node_isset(node, memtype->nodes))
> - return memtype->memtier;
> - return NULL;
After adding pgdat->memtier, it appears there's unnecessary to keep
memtype->memtier?
Best Regards,
Huang, Ying
> + pgdat = NODE_DATA(node);
> + if (!pgdat)
> + return NULL;
> + /*
> + * Since we hold memory_tier_lock, we can avoid
> + * RCU read locks when accessing the details. No
> + * parallel updates are possible here.
> + */
> + return rcu_dereference_check(pgdat->memtier,
> + lockdep_is_held(&memory_tier_lock));
> }
>
> #ifdef CONFIG_MIGRATION
> @@ -295,6 +302,8 @@ static struct memory_tier *set_node_memory_tier(int node)
> {
> struct memory_tier *memtier;
> struct memory_dev_type *memtype;
> + pg_data_t *pgdat = NODE_DATA(node);
> +
>
> lockdep_assert_held_once(&memory_tier_lock);
>
> @@ -307,6 +316,8 @@ static struct memory_tier *set_node_memory_tier(int node)
> memtype = node_memory_types[node];
> node_set(node, memtype->nodes);
> memtier = find_create_memory_tier(memtype);
> + if (!IS_ERR(memtier))
> + rcu_assign_pointer(pgdat->memtier, memtier);
> return memtier;
> }
>
> @@ -319,12 +330,25 @@ static void destroy_memory_tier(struct memory_tier *memtier)
> static bool clear_node_memory_tier(int node)
> {
> bool cleared = false;
> + pg_data_t *pgdat;
> struct memory_tier *memtier;
>
> + pgdat = NODE_DATA(node);
> + if (!pgdat)
> + return false;
> +
> + /*
> + * Make sure that anybody looking at NODE_DATA who finds
> + * a valid memtier finds memory_dev_types with nodes still
> + * linked to the memtier. We achieve this by waiting for
> + * rcu read section to finish using synchronize_rcu.
> + */
> memtier = __node_get_memory_tier(node);
> if (memtier) {
> struct memory_dev_type *memtype;
>
> + rcu_assign_pointer(pgdat->memtier, NULL);
> + synchronize_rcu();
> memtype = node_memory_types[node];
> node_clear(node, memtype->nodes);
> if (nodes_empty(memtype->nodes)) {
> @@ -422,8 +446,10 @@ static int __init memory_tier_init(void)
> panic("%s() failed to register memory tier: %ld\n",
> __func__, PTR_ERR(memtier));
>
> - for_each_node_state(node, N_MEMORY)
> + for_each_node_state(node, N_MEMORY) {
> __init_node_memory_type(node, default_dram_type);
> + rcu_assign_pointer(NODE_DATA(node)->memtier, memtier);
> + }
>
> mutex_unlock(&memory_tier_lock);
> #ifdef CONFIG_MIGRATION
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH v13 4/9] mm/demotion/dax/kmem: Set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE
2022-08-09 3:04 ` Huang, Ying
@ 2022-08-09 5:33 ` Aneesh Kumar K V
2022-08-10 1:09 ` Huang, Ying
0 siblings, 1 reply; 21+ messages in thread
From: Aneesh Kumar K V @ 2022-08-09 5:33 UTC (permalink / raw)
To: Huang, Ying
Cc: linux-mm, akpm, Wei Xu, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss
On 8/9/22 8:34 AM, Huang, Ying wrote:
> "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
>
>> By default, all nodes are assigned to the default memory tier which
>> is the memory tier designated for nodes with DRAM
>>
>> Set dax kmem device node's tier to slower memory tier by assigning
>> abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE. Low-level drivers
>> like papr_scm or ACPI NFIT can initialize memory device type to a
>> more accurate value based on device tree details or HMAT.
>
> I don't know how ACPI NFIT can help here. Can you teach me?
>
> Per my understanding, we may use the information provided by ACPI SLIT
> or HMAT (or device tree via papr_scm) to create memory types. Before
> that is implemented, we just create a memory type with default abstract
> distance.
>
My idea is to use ACPI NFIT driver that creates a persistent memory region
(nvdimm_region_create) to also create memory type and assign that to the
NUMA node mapping that region. For now NFIT driver manages all the persistent
memory region/DIMM creation (drivers/acpi/nfit/core.c). It can also do the
memory type creation using other ACPI information like SLIT/HMAT etc. Similarly
CXL driver can do the same using CDAT.
>> If the
>> kernel doesn't find the memory type initialized, a default slower
>> memory type is assigned by the kmem driver.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>> drivers/dax/kmem.c | 40 ++++++++++++++++++-
>> include/linux/memory-tiers.h | 26 ++++++++++++-
>> mm/memory-tiers.c | 74 +++++++++++++++++++++++++-----------
>> 3 files changed, 115 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
>> index a37622060fff..b5cb03307af8 100644
>> --- a/drivers/dax/kmem.c
>> +++ b/drivers/dax/kmem.c
>> @@ -11,9 +11,17 @@
>> #include <linux/fs.h>
>> #include <linux/mm.h>
>> #include <linux/mman.h>
>> +#include <linux/memory-tiers.h>
>> #include "dax-private.h"
>> #include "bus.h"
>>
>> +/*
>> + * Default abstract distance assigned to the NUMA node onlined
>> + * by DAX/kmem if the low level platform driver didn't initialize
>> + * one for this NUMA node.
>> + */
>
> We have 2 choices here.
>
> 1. The low level drivers create memory types and set
> node_memory_types[]. We need a mechanism to coordinate among multiple
> drivers. On x86, we have ACPI SLIT, HMAT. And we have platform
> independent CXL defined CDAT.
>
> 2. The high level driver (such as dax/kmem.c) coordinate among multiple
> low level drivers. For example, it may query CXL CDAT firstly, and use
> a notifier chain to query platform drivers with priority.
>
> Personally, I prefer choice 2. We can discuss this later. But can we
> make the comments more general to avoid to make decision now?
>
>> +#define MEMTIER_DEFAULT_DAX_ADISTANCE (MEMTIER_ADISTANCE_DRAM * 2)
>> +
>> /* Memory resource name used for add_memory_driver_managed(). */
>> static const char *kmem_name;
>> /* Set if any memory will remain added when the driver will be unloaded. */
>> @@ -41,6 +49,7 @@ struct dax_kmem_data {
>> struct resource *res[];
>> };
>>
>> +static struct memory_dev_type *dax_slowmem_type;
>
> I don't think "slowmem" make much sense here. There may be even slower
> memory. Just dax_mem_type or dax_kmem_type should be OK?
>
Dan Williams had a question about why we are adding an abstract distance slower than DRAM in
dax/kmem where we can also initialize faster than DRAM memory using kmem. The
"slowmem" was added to indicate that this type is slower than DRAM.
>> static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
>> {
>> struct device *dev = &dev_dax->dev;
>> @@ -62,6 +71,8 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
>> return -EINVAL;
>> }
>>
>> + init_node_memory_type(numa_node, dax_slowmem_type);
>> +
>
> I don't find error handling in this function. Per my understanding, if
> memory hot-add fails, we need to call clear_node_memory_type().
>
Added
>> for (i = 0; i < dev_dax->nr_range; i++) {
>> struct range range;
>>
>> @@ -162,6 +173,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
>> static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
>> {
>> int i, success = 0;
>> + int node = dev_dax->target_node;
>> struct device *dev = &dev_dax->dev;
>> struct dax_kmem_data *data = dev_get_drvdata(dev);
>>
>> @@ -198,6 +210,14 @@ static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
>> kfree(data->res_name);
>> kfree(data);
>> dev_set_drvdata(dev, NULL);
>> + /*
>> + * Clear the memtype association on successful unplug.
>> + * If not, we have memory blocks left which can be
>> + * offlined/onlined later. We need to keep memory_dev_type
>> + * for that. This implies this reference will be around
>> + * till next reboot.
>> + */
>> + clear_node_memory_type(node, dax_slowmem_type);
>> }
>> }
>> #else
>> @@ -228,9 +248,27 @@ static int __init dax_kmem_init(void)
>> if (!kmem_name)
>> return -ENOMEM;
>>
>> + dax_slowmem_type = kmalloc(sizeof(*dax_slowmem_type), GFP_KERNEL);
>> + if (!dax_slowmem_type) {
>> + rc = -ENOMEM;
>> + goto kmem_name_free;
>> + }
>> + dax_slowmem_type->adistance = MEMTIER_DEFAULT_DAX_ADISTANCE;
>> + INIT_LIST_HEAD(&dax_slowmem_type->tier_sibiling);
>> + dax_slowmem_type->nodes = NODE_MASK_NONE;
>> + dax_slowmem_type->memtier = NULL;
>> + kref_init(&dax_slowmem_type->kref);
>> +
>
> Here we initialize the kref to 1. So in dax_kmem_exit() we should drop
> the last reference, otherwise we cannot free the memory type?
>
Add the required destroy to dax_kmem_exit()
>> rc = dax_driver_register(&device_dax_kmem_driver);
>> if (rc)
>> - kfree_const(kmem_name);
>> + goto error_out;
>> +
>> + return rc;
>> +
>> +error_out:
>> + kfree(dax_slowmem_type);
>> +kmem_name_free:
>> + kfree_const(kmem_name);
>> return rc;
>> }
>>
>> diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
>> index cc89876899a6..7bf6f47d581a 100644
>> --- a/include/linux/memory-tiers.h
>> +++ b/include/linux/memory-tiers.h
>> @@ -2,6 +2,8 @@
>> #ifndef _LINUX_MEMORY_TIERS_H
>> #define _LINUX_MEMORY_TIERS_H
>>
>> +#include <linux/types.h>
>> +#include <linux/nodemask.h>
>> /*
>> * Each tier cover a abstrace distance chunk size of 128
>> */
>> @@ -13,12 +15,34 @@
>> #define MEMTIER_ADISTANCE_DRAM (4 * MEMTIER_CHUNK_SIZE)
>> #define MEMTIER_HOTPLUG_PRIO 100
>>
>> +struct memory_tier;
>> +struct memory_dev_type {
>> + /* list of memory types that are part of same tier as this type */
>> + struct list_head tier_sibiling;
>> + /* abstract distance for this specific memory type */
>> + int adistance;
>> + /* Nodes of same abstract distance */
>> + nodemask_t nodes;
>> + struct kref kref;
>> + struct memory_tier *memtier;
>> +};
>> +
>> #ifdef CONFIG_NUMA
>> -#include <linux/types.h>
>> extern bool numa_demotion_enabled;
>> +void init_node_memory_type(int node, struct memory_dev_type *default_type);
>> +void clear_node_memory_type(int node, struct memory_dev_type *memtype);
>>
>> #else
>>
>> #define numa_demotion_enabled false
>> +static inline void init_node_memory_type(int node, struct memory_dev_type *default_type)
>> +{
>> +
>> +}
>> +
>> +static inline void clear_node_memory_type(int node, struct memory_dev_type *memtype)
>> +{
>> +
>> +}
>> #endif /* CONFIG_NUMA */
>> #endif /* _LINUX_MEMORY_TIERS_H */
>> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
>> index 2caa5ab446b8..e07dffb67567 100644
>> --- a/mm/memory-tiers.c
>> +++ b/mm/memory-tiers.c
>> @@ -1,6 +1,4 @@
>> // SPDX-License-Identifier: GPL-2.0
>> -#include <linux/types.h>
>> -#include <linux/nodemask.h>
>> #include <linux/slab.h>
>> #include <linux/lockdep.h>
>> #include <linux/sysfs.h>
>> @@ -21,26 +19,10 @@ struct memory_tier {
>> int adistance_start;
>> };
>>
>> -struct memory_dev_type {
>> - /* list of memory types that are part of same tier as this type */
>> - struct list_head tier_sibiling;
>> - /* abstract distance for this specific memory type */
>> - int adistance;
>> - /* Nodes of same abstract distance */
>> - nodemask_t nodes;
>> - struct memory_tier *memtier;
>> -};
>> -
>> static DEFINE_MUTEX(memory_tier_lock);
>> static LIST_HEAD(memory_tiers);
>> static struct memory_dev_type *node_memory_types[MAX_NUMNODES];
>> -/*
>> - * For now let's have 4 memory tier below default DRAM tier.
>> - */
>> -static struct memory_dev_type default_dram_type = {
>> - .adistance = MEMTIER_ADISTANCE_DRAM,
>> - .tier_sibiling = LIST_HEAD_INIT(default_dram_type.tier_sibiling),
>> -};
>> +static struct memory_dev_type *default_dram_type;
>>
>> static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype)
>> {
>> @@ -96,6 +78,14 @@ static struct memory_tier *__node_get_memory_tier(int node)
>> return NULL;
>> }
>>
>> +static inline void __init_node_memory_type(int node, struct memory_dev_type *default_type)
>> +{
>> + if (!node_memory_types[node]) {
>> + node_memory_types[node] = default_type;
>> + kref_get(&default_type->kref);
>> + }
>> +}
>> +
>> static struct memory_tier *set_node_memory_tier(int node)
>> {
>> struct memory_tier *memtier;
>> @@ -107,7 +97,7 @@ static struct memory_tier *set_node_memory_tier(int node)
>> return ERR_PTR(-EINVAL);
>>
>> if (!node_memory_types[node])
>> - node_memory_types[node] = &default_dram_type;
>> + __init_node_memory_type(node, default_dram_type);
>>
>> memtype = node_memory_types[node];
>> node_set(node, memtype->nodes);
>> @@ -143,6 +133,34 @@ static bool clear_node_memory_tier(int node)
>> return cleared;
>> }
>>
>> +void init_node_memory_type(int node, struct memory_dev_type *default_type)
>> +{
>> +
>> + mutex_lock(&memory_tier_lock);
>> + __init_node_memory_type(node, default_type);
>> + mutex_unlock(&memory_tier_lock);
>> +}
>> +EXPORT_SYMBOL_GPL(init_node_memory_type);
>> +
>> +static void release_memtype(struct kref *kref)
>> +{
>> + struct memory_dev_type *memtype;
>> +
>> + memtype = container_of(kref, struct memory_dev_type, kref);
>> + kfree(memtype);
>> +}
>> +
>> +void clear_node_memory_type(int node, struct memory_dev_type *memtype)
>> +{
>> + mutex_lock(&memory_tier_lock);
>> + if (node_memory_types[node] == memtype) {
>> + node_memory_types[node] = NULL;
>> + kref_put(&memtype->kref, release_memtype);
>> + }
>> + mutex_unlock(&memory_tier_lock);
>> +}
>> +EXPORT_SYMBOL_GPL(clear_node_memory_type);
>> +
>> static int __meminit memtier_hotplug_callback(struct notifier_block *self,
>> unsigned long action, void *_arg)
>> {
>> @@ -176,17 +194,27 @@ static int __init memory_tier_init(void)
>> int node;
>> struct memory_tier *memtier;
>>
>> + default_dram_type = kmalloc(sizeof(*default_dram_type), GFP_KERNEL);
>> + if (!default_dram_type)
>> + panic("%s() failed to allocate default DRAM tier\n", __func__);
>> +
>> mutex_lock(&memory_tier_lock);
>> +
>> + /* For now let's have 4 memory tier below default DRAM tier. */
>> + default_dram_type->adistance = MEMTIER_ADISTANCE_DRAM;
>> + INIT_LIST_HEAD(&default_dram_type->tier_sibiling);
>> + default_dram_type->memtier = NULL;
>> + kref_init(&default_dram_type->kref);
>
> It appears that we can define a function to initialize a memory type.
I added the below
static inline struct memory_dev_type *alloc_memory_type(int adistance)
static inline void destroy_memory_type(struct memory_dev_type *memtype)
>
>> /* CPU only nodes are not part of memory tiers. */
>> - default_dram_type.nodes = node_states[N_MEMORY];
>> + default_dram_type->nodes = node_states[N_MEMORY];
>>
>> - memtier = find_create_memory_tier(&default_dram_type);
>> + memtier = find_create_memory_tier(default_dram_type);
>> if (IS_ERR(memtier))
>> panic("%s() failed to register memory tier: %ld\n",
>> __func__, PTR_ERR(memtier));
>>
>> for_each_node_state(node, N_MEMORY)
>> - node_memory_types[node] = &default_dram_type;
>> + __init_node_memory_type(node, default_dram_type);
>>
>> mutex_unlock(&memory_tier_lock);
>
> Best Regards,
> Huang, Ying
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH v13 1/9] mm/demotion: Add support for explicit memory tiers
2022-08-09 1:58 ` Huang, Ying
@ 2022-08-09 5:34 ` Aneesh Kumar K V
0 siblings, 0 replies; 21+ messages in thread
From: Aneesh Kumar K V @ 2022-08-09 5:34 UTC (permalink / raw)
To: Huang, Ying
Cc: linux-mm, akpm, Wei Xu, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss
On 8/9/22 7:28 AM, Huang, Ying wrote:
> "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
>
>> In the current kernel, memory tiers are defined implicitly via a demotion path
>> relationship between NUMA nodes, which is created during the kernel
>> initialization and updated when a NUMA node is hot-added or hot-removed. The
>> current implementation puts all nodes with CPU into the highest tier, and builds
>> the tier hierarchy by establishing the per-node demotion targets based on the
>> distances between nodes.
>>
>> This current memory tier kernel implementation needs to be improved for several
>> important use cases,
>>
>> The current tier initialization code always initializes each memory-only NUMA
>> node into a lower tier. But a memory-only NUMA node may have a high performance
>> memory device (e.g. a DRAM-backed memory-only node on a virtual machine) that
>> should be put into a higher tier.
>>
>> The current tier hierarchy always puts CPU nodes into the top tier. But on a
>> system with HBM or GPU devices, the memory-only NUMA nodes mapping these devices
>> should be in the top tier, and DRAM nodes with CPUs are better to be placed into
>> the next lower tier.
>>
>> With current kernel higher tier node can only be demoted to nodes with shortest
>> distance on the next lower tier as defined by the demotion path, not any other
>> node from any lower tier. This strict, demotion order does not work in all use
>> cases (e.g. some use cases may want to allow cross-socket demotion to another
>> node in the same demotion tier as a fallback when the preferred demotion node is
>> out of space), This demotion order is also inconsistent with the page allocation
>> fallback order when all the nodes in a higher tier are out of space: The page
>> allocation can fall back to any node from any lower tier, whereas the demotion
>> order doesn't allow that.
>>
>> This patch series address the above by defining memory tiers explicitly.
>>
>> Linux kernel presents memory devices as NUMA nodes and each memory device is of
>> a specific type. The memory type of a device is represented by its abstract
>> distance. A memory tier corresponds to a range of abstract distance. This allows
>> for classifying memory devices with a specific performance range into a memory
>> tier.
>>
>> This patch configures the range/chunk size to be 128. The default DRAM abstract
>> distance is 512. We can have 4 memory tiers below the default DRAM with abstract
>> distance range 0 - 127, 127 - 255, 256- 383, 384 - 511. Faster memory devices
>> can be placed in these faster(higher) memory tiers. Slower memory devices like
>> persistent memory will have abstract distance higher than the default DRAM
>> level.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>> include/linux/memory-tiers.h | 15 +++++
>> mm/Makefile | 1 +
>> mm/memory-tiers.c | 107 +++++++++++++++++++++++++++++++++++
>> 3 files changed, 123 insertions(+)
>> create mode 100644 include/linux/memory-tiers.h
>> create mode 100644 mm/memory-tiers.c
>>
>> diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
>> new file mode 100644
>> index 000000000000..bc7c1b799bef
>> --- /dev/null
>> +++ b/include/linux/memory-tiers.h
>> @@ -0,0 +1,15 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +#ifndef _LINUX_MEMORY_TIERS_H
>> +#define _LINUX_MEMORY_TIERS_H
>> +
>> +/*
>> + * Each tier cover a abstrace distance chunk size of 128
>> + */
>> +#define MEMTIER_CHUNK_BITS 7
>> +#define MEMTIER_CHUNK_SIZE (1 << MEMTIER_CHUNK_BITS)
>> +/*
>> + * Smaller abstract distance value imply faster(higher) memory tiers.
>> + */
>> +#define MEMTIER_ADISTANCE_DRAM (4 * MEMTIER_CHUNK_SIZE)
>> +
>> +#endif /* _LINUX_MEMORY_TIERS_H */
>> diff --git a/mm/Makefile b/mm/Makefile
>> index 6f9ffa968a1a..d30acebc2164 100644
>> --- a/mm/Makefile
>> +++ b/mm/Makefile
>> @@ -92,6 +92,7 @@ obj-$(CONFIG_KFENCE) += kfence/
>> obj-$(CONFIG_FAILSLAB) += failslab.o
>> obj-$(CONFIG_MEMTEST) += memtest.o
>> obj-$(CONFIG_MIGRATION) += migrate.o
>> +obj-$(CONFIG_NUMA) += memory-tiers.o
>> obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o
>> obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
>> obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
>> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
>> new file mode 100644
>> index 000000000000..78b311d9bde9
>> --- /dev/null
>> +++ b/mm/memory-tiers.c
>> @@ -0,0 +1,107 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +#include <linux/types.h>
>> +#include <linux/nodemask.h>
>> +#include <linux/slab.h>
>> +#include <linux/lockdep.h>
>> +#include <linux/memory-tiers.h>
>> +
>> +struct memory_tier {
>> + /* hierarchy of memory tiers */
>> + struct list_head list;
>> + /* list of all memory types part of this tier */
>> + struct list_head memory_types;
>> + /*
>> + * start value of abstract distance. memory tier maps
>> + * an abstract distance range,
>> + * adistance_start .. adistance_start + MEMTIER_CHUNK_SIZE
>> + */
>> + int adistance_start;
>> +};
>> +
>> +struct memory_dev_type {
>> + /* list of memory types that are part of same tier as this type */
>> + struct list_head tier_sibiling;
>> + /* abstract distance for this specific memory type */
>> + int adistance;
>> + /* Nodes of same abstract distance */
>> + nodemask_t nodes;
>> + struct memory_tier *memtier;
>> +};
>> +
>> +static DEFINE_MUTEX(memory_tier_lock);
>> +static LIST_HEAD(memory_tiers);
>> +static struct memory_dev_type *node_memory_types[MAX_NUMNODES];
>> +/*
>> + * For now let's have 4 memory tier below default DRAM tier.
>> + */
>> +static struct memory_dev_type default_dram_type = {
>> + .adistance = MEMTIER_ADISTANCE_DRAM,
>> + .tier_sibiling = LIST_HEAD_INIT(default_dram_type.tier_sibiling),
>> +};
>> +
>> +static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype)
>> +{
>> + bool found_slot = false;
>> + struct memory_tier *memtier, *new_memtier;
>> + int adistance = memtype->adistance;
>> + unsigned int memtier_adistance_chunk_size = MEMTIER_CHUNK_SIZE;
>> +
>> + lockdep_assert_held_once(&memory_tier_lock);
>> +
>> + /*
>> + * If the memtype is already part of a memory tier,
>> + * just return that.
>> + */
>> + if (memtype->memtier)
>> + return memtype->memtier;
>> +
>> + adistance = round_down(adistance, memtier_adistance_chunk_size);
>> + list_for_each_entry(memtier, &memory_tiers, list) {
>> + if (adistance == memtier->adistance_start) {
>> + memtype->memtier = memtier;
>> + list_add(&memtype->tier_sibiling, &memtier->memory_types);
>> + return memtier;
>> + } else if (adistance < memtier->adistance_start) {
>> + found_slot = true;
>> + break;
>> + }
>> + }
>> +
>> + new_memtier = kmalloc(sizeof(struct memory_tier), GFP_KERNEL);
>> + if (!new_memtier)
>> + return ERR_PTR(-ENOMEM);
>> +
>> + new_memtier->adistance_start = adistance;
>> + INIT_LIST_HEAD(&new_memtier->list);
>> + INIT_LIST_HEAD(&new_memtier->memory_types);
>> + if (found_slot)
>> + list_add_tail(&new_memtier->list, &memtier->list);
>> + else
>> + list_add_tail(&new_memtier->list, &memory_tiers);
>> + memtype->memtier = new_memtier;
>> + list_add(&memtype->tier_sibiling, &new_memtier->memory_types);
>> + return new_memtier;
>> +}
>> +
>> +static int __init memory_tier_init(void)
>> +{
>> + int node;
>> + struct memory_tier *memtier;
>> +
>> + mutex_lock(&memory_tier_lock);
>> + /* CPU only nodes are not part of memory tiers. */
>> + default_dram_type.nodes = node_states[N_MEMORY];
>> +
>> + memtier = find_create_memory_tier(&default_dram_type);
>> + if (IS_ERR(memtier))
>> + panic("%s() failed to register memory tier: %ld\n",
>> + __func__, PTR_ERR(memtier));
>> +
>> + for_each_node_state(node, N_MEMORY)
>> + node_memory_types[node] = &default_dram_type;
>
> Although not absolutely necessary, it seems better to set
> node_memory_types[] before adding nodes to the memory type and adding
> the memory type to the memory tier.
>
>
updated.
-aneesh
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH v13 6/9] mm/demotion: Add pg_data_t member to track node memory tier details
2022-08-09 5:21 ` Huang, Ying
@ 2022-08-09 5:41 ` Aneesh Kumar K V
2022-08-10 1:03 ` Huang, Ying
0 siblings, 1 reply; 21+ messages in thread
From: Aneesh Kumar K V @ 2022-08-09 5:41 UTC (permalink / raw)
To: Huang, Ying
Cc: linux-mm, akpm, Wei Xu, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss
On 8/9/22 10:51 AM, Huang, Ying wrote:
> "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
>
>> Also update different helpes to use NODE_DATA()->memtier. Since
>> node specific memtier can change based on the reassignment of
>> NUMA node to a different memory tiers, accessing NODE_DATA()->memtier
>> needs to happen under an rcu read lock or memory_tier_lock.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>> include/linux/mmzone.h | 3 +++
>> mm/memory-tiers.c | 38 ++++++++++++++++++++++++++++++++------
>> 2 files changed, 35 insertions(+), 6 deletions(-)
>>
>> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
>> index aab70355d64f..353812495a70 100644
>> --- a/include/linux/mmzone.h
>> +++ b/include/linux/mmzone.h
>> @@ -928,6 +928,9 @@ typedef struct pglist_data {
>> /* Per-node vmstats */
>> struct per_cpu_nodestat __percpu *per_cpu_nodestats;
>> atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS];
>> +#ifdef CONFIG_NUMA
>> + struct memory_tier __rcu *memtier;
>> +#endif
>> } pg_data_t;
>>
>> #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
>> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
>> index 02e514e87d5c..3778ac6a44a1 100644
>> --- a/mm/memory-tiers.c
>> +++ b/mm/memory-tiers.c
>> @@ -5,6 +5,7 @@
>> #include <linux/kobject.h>
>> #include <linux/memory.h>
>> #include <linux/random.h>
>> +#include <linux/mmzone.h>
>> #include <linux/memory-tiers.h>
>>
>> #include "internal.h"
>> @@ -137,12 +138,18 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
>>
>> static struct memory_tier *__node_get_memory_tier(int node)
>> {
>> - struct memory_dev_type *memtype;
>> + pg_data_t *pgdat;
>>
>> - memtype = node_memory_types[node];
>> - if (memtype && node_isset(node, memtype->nodes))
>> - return memtype->memtier;
>> - return NULL;
>
> After adding pgdat->memtier, it appears there's unnecessary to keep
> memtype->memtier?
>
It do simplify find_create_memory_tier() where I use if (memtype->memtier)
to check whether the memtype is already added to a memory tier. I could switch
that to list_empty(memtype->tier_sibiling). But I felt the current one is much
cleaner
.
-aneesh
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH v13 9/9] lib/nodemask: Optimize node_random for nodemask with single NUMA node
2022-08-09 3:13 ` Huang, Ying
@ 2022-08-09 5:43 ` Aneesh Kumar K V
0 siblings, 0 replies; 21+ messages in thread
From: Aneesh Kumar K V @ 2022-08-09 5:43 UTC (permalink / raw)
To: Huang, Ying
Cc: linux-mm, akpm, Wei Xu, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss
On 8/9/22 8:43 AM, Huang, Ying wrote:
> "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
>
>> The most common case for certain node_random usage (demotion nodemask) is with
>> nodemask weight 1. We can avoid calling get_random_init() in that case and
>> always return the only node set in the nodemask.
>
> I think that this patch can sit between [5/9] and [6/9], just after it
> is used.
>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>> lib/nodemask.c | 15 ++++++++++++---
>> 1 file changed, 12 insertions(+), 3 deletions(-)
>>
>> diff --git a/lib/nodemask.c b/lib/nodemask.c
>> index e22647f5181b..c91a6b0404a5 100644
>> --- a/lib/nodemask.c
>> +++ b/lib/nodemask.c
>> @@ -20,12 +20,21 @@ EXPORT_SYMBOL(__next_node_in);
>> */
>> int node_random(const nodemask_t *maskp)
>> {
>> - int w, bit = NUMA_NO_NODE;
>> + int w, bit;
>>
>> w = nodes_weight(*maskp);
>> - if (w)
>> + switch (w) {
>> + case 0:
>> + bit = NUMA_NO_NODE;
>> + break;
>> + case 1:
>> + bit = __first_node(maskp);
>
> Per my understanding, first_node() is the formal API and we should use
> that? Just like we use nodes_weight() instead of __nodes_weight().
>
updated.
-aneesh
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH v13 6/9] mm/demotion: Add pg_data_t member to track node memory tier details
2022-08-09 5:41 ` Aneesh Kumar K V
@ 2022-08-10 1:03 ` Huang, Ying
0 siblings, 0 replies; 21+ messages in thread
From: Huang, Ying @ 2022-08-10 1:03 UTC (permalink / raw)
To: Aneesh Kumar K V
Cc: linux-mm, akpm, Wei Xu, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss
Aneesh Kumar K V <aneesh.kumar@linux.ibm.com> writes:
> On 8/9/22 10:51 AM, Huang, Ying wrote:
>> "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
>>
>>> Also update different helpes to use NODE_DATA()->memtier. Since
>>> node specific memtier can change based on the reassignment of
>>> NUMA node to a different memory tiers, accessing NODE_DATA()->memtier
>>> needs to happen under an rcu read lock or memory_tier_lock.
>>>
>>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>>> ---
>>> include/linux/mmzone.h | 3 +++
>>> mm/memory-tiers.c | 38 ++++++++++++++++++++++++++++++++------
>>> 2 files changed, 35 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
>>> index aab70355d64f..353812495a70 100644
>>> --- a/include/linux/mmzone.h
>>> +++ b/include/linux/mmzone.h
>>> @@ -928,6 +928,9 @@ typedef struct pglist_data {
>>> /* Per-node vmstats */
>>> struct per_cpu_nodestat __percpu *per_cpu_nodestats;
>>> atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS];
>>> +#ifdef CONFIG_NUMA
>>> + struct memory_tier __rcu *memtier;
>>> +#endif
>>> } pg_data_t;
>>>
>>> #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
>>> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
>>> index 02e514e87d5c..3778ac6a44a1 100644
>>> --- a/mm/memory-tiers.c
>>> +++ b/mm/memory-tiers.c
>>> @@ -5,6 +5,7 @@
>>> #include <linux/kobject.h>
>>> #include <linux/memory.h>
>>> #include <linux/random.h>
>>> +#include <linux/mmzone.h>
>>> #include <linux/memory-tiers.h>
>>>
>>> #include "internal.h"
>>> @@ -137,12 +138,18 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
>>>
>>> static struct memory_tier *__node_get_memory_tier(int node)
>>> {
>>> - struct memory_dev_type *memtype;
>>> + pg_data_t *pgdat;
>>>
>>> - memtype = node_memory_types[node];
>>> - if (memtype && node_isset(node, memtype->nodes))
>>> - return memtype->memtier;
>>> - return NULL;
>>
>> After adding pgdat->memtier, it appears there's unnecessary to keep
>> memtype->memtier?
>>
>
> It do simplify find_create_memory_tier() where I use if (memtype->memtier)
> to check whether the memtype is already added to a memory tier. I could switch
> that to list_empty(memtype->tier_sibiling). But I felt the current one is much
> cleaner
I prefer "list_empty(memtype->tier_sibiling)". But I will let you to
decide.
Best Regards,
Huang, Ying
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH v13 4/9] mm/demotion/dax/kmem: Set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE
2022-08-09 5:33 ` Aneesh Kumar K V
@ 2022-08-10 1:09 ` Huang, Ying
0 siblings, 0 replies; 21+ messages in thread
From: Huang, Ying @ 2022-08-10 1:09 UTC (permalink / raw)
To: Aneesh Kumar K V
Cc: linux-mm, akpm, Wei Xu, Yang Shi, Davidlohr Bueso, Tim C Chen,
Michal Hocko, Linux Kernel Mailing List, Hesham Almatary,
Dave Hansen, Jonathan Cameron, Alistair Popple, Dan Williams,
Johannes Weiner, jvgediya.oss
Aneesh Kumar K V <aneesh.kumar@linux.ibm.com> writes:
> On 8/9/22 8:34 AM, Huang, Ying wrote:
>> "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
>>
>>> By default, all nodes are assigned to the default memory tier which
>>> is the memory tier designated for nodes with DRAM
>>>
>>> Set dax kmem device node's tier to slower memory tier by assigning
>>> abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE. Low-level drivers
>>> like papr_scm or ACPI NFIT can initialize memory device type to a
>>> more accurate value based on device tree details or HMAT.
>>
>> I don't know how ACPI NFIT can help here. Can you teach me?
>>
>> Per my understanding, we may use the information provided by ACPI SLIT
>> or HMAT (or device tree via papr_scm) to create memory types. Before
>> that is implemented, we just create a memory type with default abstract
>> distance.
>>
>
> My idea is to use ACPI NFIT driver that creates a persistent memory region
> (nvdimm_region_create) to also create memory type and assign that to the
> NUMA node mapping that region. For now NFIT driver manages all the persistent
> memory region/DIMM creation (drivers/acpi/nfit/core.c). It can also do the
> memory type creation using other ACPI information like SLIT/HMAT etc. Similarly
> CXL driver can do the same using CDAT.
I still think that it's better to create memory types in dax/kmem.c and
CXL driver. But we can discuss further on that later.
Best Regards,
Huang, Ying
^ permalink raw reply [flat|nested] 21+ messages in thread
end of thread, other threads:[~2022-08-10 1:10 UTC | newest]
Thread overview: 21+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-08-08 6:25 [PATCH v13 0/9] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
2022-08-08 6:25 ` [PATCH v13 1/9] mm/demotion: Add support for explicit memory tiers Aneesh Kumar K.V
2022-08-09 1:58 ` Huang, Ying
2022-08-09 5:34 ` Aneesh Kumar K V
2022-08-08 6:25 ` [PATCH v13 2/9] mm/demotion: Move memory demotion related code Aneesh Kumar K.V
2022-08-08 6:25 ` [PATCH v13 3/9] mm/demotion: Add hotplug callbacks to handle new numa node onlined Aneesh Kumar K.V
2022-08-08 6:25 ` [PATCH v13 4/9] mm/demotion/dax/kmem: Set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE Aneesh Kumar K.V
2022-08-09 3:04 ` Huang, Ying
2022-08-09 5:33 ` Aneesh Kumar K V
2022-08-10 1:09 ` Huang, Ying
2022-08-08 6:25 ` [PATCH v13 5/9] mm/demotion: Build demotion targets based on explicit memory tiers Aneesh Kumar K.V
2022-08-08 6:25 ` [PATCH v13 6/9] mm/demotion: Add pg_data_t member to track node memory tier details Aneesh Kumar K.V
2022-08-09 3:07 ` Huang, Ying
2022-08-09 5:21 ` Huang, Ying
2022-08-09 5:41 ` Aneesh Kumar K V
2022-08-10 1:03 ` Huang, Ying
2022-08-08 6:25 ` [PATCH v13 7/9] mm/demotion: Demote pages according to allocation fallback order Aneesh Kumar K.V
2022-08-08 6:26 ` [PATCH v13 8/9] mm/demotion: Update node_is_toptier to work with memory tiers Aneesh Kumar K.V
2022-08-08 6:26 ` [PATCH v13 9/9] lib/nodemask: Optimize node_random for nodemask with single NUMA node Aneesh Kumar K.V
2022-08-09 3:13 ` Huang, Ying
2022-08-09 5:43 ` Aneesh Kumar K V
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.