From 992bf77591cb7e696fcc59aa7e64d1200b673513 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 18 Aug 2022 18:40:33 +0530 Subject: [PATCH 01/11] mm/demotion: add support for explicit memory tiers Patch series "mm/demotion: Memory tiers and demotion", v15. 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. This patch (of 10): 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. [akpm@linux-foundation.org: fix comment, per Aneesh] Link: https://lkml.kernel.org/r/20220818131042.113280-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20220818131042.113280-2-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: Jagdish Gediya Cc: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/memory-tiers.h | 18 +++++ mm/Makefile | 1 + mm/memory-tiers.c | 129 +++++++++++++++++++++++++++++++++++ 3 files changed, 148 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..ecada7bf4091 --- /dev/null +++ b/include/linux/memory-tiers.h @@ -0,0 +1,18 @@ +/* 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 values imply faster (higher) memory tiers. Offset + * the DRAM adistance so that we can accommodate devices with a slightly lower + * adistance value (slightly faster) than default DRAM adistance to be part of + * the same memory tier. + */ +#define MEMTIER_ADISTANCE_DRAM ((4 * MEMTIER_CHUNK_SIZE) + (MEMTIER_CHUNK_SIZE >> 1)) + +#endif /* _LINUX_MEMORY_TIERS_H */ diff --git a/mm/Makefile b/mm/Makefile index 9a564f836403..488f604e77e0 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..1f494e69776a --- /dev/null +++ b/mm/memory-tiers.c @@ -0,0 +1,129 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include + +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 we can have 4 faster memory tiers with smaller adistance + * than 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 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 int __init memory_tier_init(void) +{ + int node; + struct memory_tier *memtier; + + mutex_lock(&memory_tier_lock); + /* + * Look at all the existing N_MEMORY nodes and add them to + * default memory tier or to a tier if we already have memory + * types assigned. + */ + for_each_node_state(node, N_MEMORY) { + memtier = set_node_memory_tier(node); + if (IS_ERR(memtier)) + /* + * Continue with memtiers we are able to setup + */ + break; + } + mutex_unlock(&memory_tier_lock); + + return 0; +} +subsys_initcall(memory_tier_init); From 9195244022788935eac0df16132394ffa5613542 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 18 Aug 2022 18:40:34 +0530 Subject: [PATCH 02/11] mm/demotion: move memory demotion related code This moves memory demotion related code to mm/memory-tiers.c. No functional change in this patch. Link: https://lkml.kernel.org/r/20220818131042.113280-3-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/memory-tiers.h | 8 +++++ include/linux/migrate.h | 2 -- mm/memory-tiers.c | 64 ++++++++++++++++++++++++++++++++++++ mm/migrate.c | 62 ++-------------------------------- mm/vmscan.c | 1 + 5 files changed, 75 insertions(+), 62 deletions(-) diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index ecada7bf4091..5f24396da76c 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -15,4 +15,12 @@ */ #define MEMTIER_ADISTANCE_DRAM ((4 * MEMTIER_CHUNK_SIZE) + (MEMTIER_CHUNK_SIZE >> 1)) +#ifdef CONFIG_NUMA +#include +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 22c0a0cf5e0c..96f8c84413fe 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 1f494e69776a..f3dc3318d931 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -3,6 +3,8 @@ #include #include #include +#include +#include #include struct memory_tier { @@ -127,3 +129,65 @@ 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 06a653977835..30477cf4868d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2590,64 +2590,6 @@ void __init migrate_on_reclaim_init(void) set_migration_target_nodes(); cpus_read_unlock(); } - -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 1628521b8eda..b7e9d8f8f649 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #include #include From c6123a19c9f040e597f55f856c679651c26b31d1 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 18 Aug 2022 18:40:35 +0530 Subject: [PATCH 03/11] mm/demotion: add hotplug callbacks to handle new numa node onlined If the new NUMA node onlined doesn't have a abstract distance assigned, the kernel adds the NUMA node to default memory tier. [aneesh.kumar@linux.ibm.com: fix kernel error with memory hotplug] Link: https://lkml.kernel.org/r/20220825092019.379069-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20220818131042.113280-4-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/memory-tiers.h | 1 + mm/memory-tiers.c | 68 ++++++++++++++++++++++++++++++++++++ 2 files changed, 69 insertions(+) diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index 5f24396da76c..7ae6308b2191 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -14,6 +14,7 @@ * the same memory tier. */ #define MEMTIER_ADISTANCE_DRAM ((4 * MEMTIER_CHUNK_SIZE) + (MEMTIER_CHUNK_SIZE >> 1)) +#define MEMTIER_HOTPLUG_PRIO 100 #ifdef CONFIG_NUMA #include diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index f3dc3318d931..f74e077533ac 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -5,6 +5,7 @@ #include #include #include +#include #include struct memory_tier { @@ -105,6 +106,72 @@ static struct memory_tier *set_node_memory_tier(int node) return 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 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_init(&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; @@ -126,6 +193,7 @@ 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); From 7b88bda3761b95856cf97822efe8281c8100067b Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 18 Aug 2022 18:40:36 +0530 Subject: [PATCH 04/11] mm/demotion/dax/kmem: set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE 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. [aneesh.kumar@linux.ibm.com: assign correct memory type for multiple dax devices with the same node affinity] Link: https://lkml.kernel.org/r/20220826100224.542312-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20220818131042.113280-5-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: SeongJae Park Signed-off-by: Andrew Morton --- drivers/dax/kmem.c | 44 ++++++++++++-- include/linux/memory-tiers.h | 42 ++++++++++++- mm/memory-tiers.c | 114 ++++++++++++++++++++++++++++------- 3 files changed, 172 insertions(+), 28 deletions(-) diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c index a37622060fff..4852a2dbdb27 100644 --- a/drivers/dax/kmem.c +++ b/drivers/dax/kmem.c @@ -11,9 +11,17 @@ #include #include #include +#include #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 * 5) + /* 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; @@ -79,11 +88,13 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) return -EINVAL; } - data = kzalloc(struct_size(data, res, dev_dax->nr_range), GFP_KERNEL); - if (!data) - return -ENOMEM; + init_node_memory_type(numa_node, dax_slowmem_type); rc = -ENOMEM; + data = kzalloc(struct_size(data, res, dev_dax->nr_range), GFP_KERNEL); + if (!data) + goto err_dax_kmem_data; + data->res_name = kstrdup(dev_name(dev), GFP_KERNEL); if (!data->res_name) goto err_res_name; @@ -155,6 +166,8 @@ err_reg_mgid: kfree(data->res_name); err_res_name: kfree(data); +err_dax_kmem_data: + clear_node_memory_type(numa_node, dax_slowmem_type); return rc; } @@ -162,6 +175,7 @@ err_res_name: 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 +212,14 @@ 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 +250,22 @@ static int __init dax_kmem_init(void) if (!kmem_name) return -ENOMEM; + dax_slowmem_type = alloc_memory_type(MEMTIER_DEFAULT_DAX_ADISTANCE); + if (IS_ERR(dax_slowmem_type)) { + rc = PTR_ERR(dax_slowmem_type); + goto err_dax_slowmem_type; + } + rc = dax_driver_register(&device_dax_kmem_driver); if (rc) - kfree_const(kmem_name); + goto error_dax_driver; + + return rc; + +error_dax_driver: + destroy_memory_type(dax_slowmem_type); +err_dax_slowmem_type: + kfree_const(kmem_name); return rc; } @@ -239,6 +274,7 @@ static void __exit dax_kmem_exit(void) dax_driver_unregister(&device_dax_kmem_driver); if (!any_hotremove_failed) kfree_const(kmem_name); + destroy_memory_type(dax_slowmem_type); } MODULE_AUTHOR("Intel Corporation"); diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index 7ae6308b2191..49d281866dca 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -2,6 +2,9 @@ #ifndef _LINUX_MEMORY_TIERS_H #define _LINUX_MEMORY_TIERS_H +#include +#include +#include /* * Each tier cover a abstrace distance chunk size of 128 */ @@ -16,12 +19,49 @@ #define MEMTIER_ADISTANCE_DRAM ((4 * MEMTIER_CHUNK_SIZE) + (MEMTIER_CHUNK_SIZE >> 1)) #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 extern bool numa_demotion_enabled; +struct memory_dev_type *alloc_memory_type(int adistance); +void destroy_memory_type(struct memory_dev_type *memtype); +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 +/* + * CONFIG_NUMA implementation returns non NULL error. + */ +static inline struct memory_dev_type *alloc_memory_type(int adistance) +{ + return NULL; +} + +static inline void destroy_memory_type(struct memory_dev_type *memtype) +{ + +} + +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 f74e077533ac..babc10a5cc13 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -1,6 +1,4 @@ // SPDX-License-Identifier: GPL-2.0 -#include -#include #include #include #include @@ -21,27 +19,15 @@ 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; +struct node_memory_type_map { + struct memory_dev_type *memtype; + int map_count; }; static DEFINE_MUTEX(memory_tier_lock); static LIST_HEAD(memory_tiers); -static struct memory_dev_type *node_memory_types[MAX_NUMNODES]; -/* - * For now we can have 4 faster memory tiers with smaller adistance - * than 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 node_memory_type_map node_memory_types[MAX_NUMNODES]; +static struct memory_dev_type *default_dram_type; static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype) { @@ -87,6 +73,24 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty return new_memtier; } +static inline void __init_node_memory_type(int node, struct memory_dev_type *memtype) +{ + if (!node_memory_types[node].memtype) + node_memory_types[node].memtype = memtype; + /* + * for each device getting added in the same NUMA node + * with this specific memtype, bump the map count. We + * Only take memtype device reference once, so that + * changing a node memtype can be done by droping the + * only reference count taken here. + */ + + if (node_memory_types[node].memtype == memtype) { + if (!node_memory_types[node].map_count++) + kref_get(&memtype->kref); + } +} + static struct memory_tier *set_node_memory_tier(int node) { struct memory_tier *memtier; @@ -97,10 +101,9 @@ static struct memory_tier *set_node_memory_tier(int node) if (!node_state(node, N_MEMORY)) 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]; + memtype = node_memory_types[node].memtype; node_set(node, memtype->nodes); memtier = find_create_memory_tier(memtype); return memtier; @@ -131,7 +134,7 @@ static bool clear_node_memory_tier(int node) if (memtier) { struct memory_dev_type *memtype; - memtype = node_memory_types[node]; + memtype = node_memory_types[node].memtype; node_clear(node, memtype->nodes); if (nodes_empty(memtype->nodes)) { list_del_init(&memtype->tier_sibiling); @@ -144,6 +147,63 @@ static bool clear_node_memory_tier(int node) return cleared; } +static void release_memtype(struct kref *kref) +{ + struct memory_dev_type *memtype; + + memtype = container_of(kref, struct memory_dev_type, kref); + kfree(memtype); +} + +struct memory_dev_type *alloc_memory_type(int adistance) +{ + struct memory_dev_type *memtype; + + memtype = kmalloc(sizeof(*memtype), GFP_KERNEL); + if (!memtype) + return ERR_PTR(-ENOMEM); + + memtype->adistance = adistance; + INIT_LIST_HEAD(&memtype->tier_sibiling); + memtype->nodes = NODE_MASK_NONE; + memtype->memtier = NULL; + kref_init(&memtype->kref); + return memtype; +} +EXPORT_SYMBOL_GPL(alloc_memory_type); + +void destroy_memory_type(struct memory_dev_type *memtype) +{ + kref_put(&memtype->kref, release_memtype); +} +EXPORT_SYMBOL_GPL(destroy_memory_type); + +void init_node_memory_type(int node, struct memory_dev_type *memtype) +{ + + mutex_lock(&memory_tier_lock); + __init_node_memory_type(node, memtype); + mutex_unlock(&memory_tier_lock); +} +EXPORT_SYMBOL_GPL(init_node_memory_type); + +void clear_node_memory_type(int node, struct memory_dev_type *memtype) +{ + mutex_lock(&memory_tier_lock); + if (node_memory_types[node].memtype == memtype) + node_memory_types[node].map_count--; + /* + * If we umapped all the attached devices to this node, + * clear the node memory type. + */ + if (!node_memory_types[node].map_count) { + node_memory_types[node].memtype = 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) { @@ -178,6 +238,14 @@ static int __init memory_tier_init(void) struct memory_tier *memtier; mutex_lock(&memory_tier_lock); + /* + * For now we can have 4 faster memory tiers with smaller adistance + * than default DRAM tier. + */ + default_dram_type = alloc_memory_type(MEMTIER_ADISTANCE_DRAM); + if (!default_dram_type) + panic("%s() failed to allocate default DRAM tier\n", __func__); + /* * Look at all the existing N_MEMORY nodes and add them to * default memory tier or to a tier if we already have memory From 6c542ab75714fe90dae292aeb3e91ac53f5ff599 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 18 Aug 2022 18:40:37 +0530 Subject: [PATCH 05/11] mm/demotion: build demotion targets based on explicit memory tiers 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. Link: https://lkml.kernel.org/r/20220818131042.113280-6-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/memory-tiers.h | 13 ++ include/linux/migrate.h | 13 -- mm/memory-tiers.c | 238 +++++++++++++++++++-- mm/migrate.c | 394 ----------------------------------- mm/vmstat.c | 4 - 5 files changed, 239 insertions(+), 423 deletions(-) diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index 49d281866dca..ce9c6bac6725 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -37,6 +37,14 @@ struct memory_dev_type *alloc_memory_type(int adistance); void destroy_memory_type(struct memory_dev_type *memtype); 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 @@ -63,5 +71,10 @@ 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 96f8c84413fe..704a04f5a074 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 babc10a5cc13..ea57fc1f37ac 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -6,6 +6,8 @@ #include #include +#include "internal.h" + struct memory_tier { /* hierarchy of memory tiers */ struct list_head list; @@ -19,6 +21,10 @@ struct memory_tier { int adistance_start; }; +struct demotion_nodes { + nodemask_t preferred; +}; + struct node_memory_type_map { struct memory_dev_type *memtype; int map_count; @@ -28,6 +34,66 @@ static DEFINE_MUTEX(memory_tier_lock); static LIST_HEAD(memory_tiers); static struct node_memory_type_map node_memory_types[MAX_NUMNODES]; static struct memory_dev_type *default_dram_type; +#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 = + * node_demotion[3].preferred = + * + * 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 = + * node_demotion[1].preferred = + * node_demotion[2].preferred = + * + * 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 = + * + */ +static struct demotion_nodes *node_demotion __read_mostly; +#endif /* CONFIG_MIGRATION */ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype) { @@ -73,6 +139,154 @@ 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; +} + +#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 *memtype) { if (!node_memory_types[node].memtype) @@ -109,16 +323,6 @@ static struct memory_tier *set_node_memory_tier(int node) return 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 void destroy_memory_tier(struct memory_tier *memtier) { list_del(&memtier->list); @@ -207,6 +411,7 @@ 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; /* @@ -219,12 +424,15 @@ 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; } @@ -237,6 +445,11 @@ static int __init memory_tier_init(void) int node; struct memory_tier *memtier; +#ifdef CONFIG_MIGRATION + node_demotion = kcalloc(nr_node_ids, sizeof(struct demotion_nodes), + GFP_KERNEL); + WARN_ON(!node_demotion); +#endif mutex_lock(&memory_tier_lock); /* * For now we can have 4 faster memory tiers with smaller adistance @@ -259,6 +472,7 @@ static int __init memory_tier_init(void) */ break; } + establish_demotion_targets(); mutex_unlock(&memory_tier_lock); hotplug_memory_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_PRIO); diff --git a/mm/migrate.c b/mm/migrate.c index 30477cf4868d..2a2329bf7c1a 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2198,398 +2198,4 @@ out: 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 c109167a669c..779f1ea6e8ea 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -28,7 +28,6 @@ #include #include #include -#include #include "internal.h" @@ -2068,7 +2067,6 @@ 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; @@ -2093,7 +2091,6 @@ static int vmstat_cpu_dead(unsigned int cpu) return 0; node_clear_state(node, N_CPU); - set_migration_target_nodes(); return 0; } @@ -2126,7 +2123,6 @@ 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); From 7766cf7a7e7545ab434a16c6f9531b09efe14dc1 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 18 Aug 2022 18:40:38 +0530 Subject: [PATCH 06/11] mm/demotion: add pg_data_t member to track node memory tier details 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. Link: https://lkml.kernel.org/r/20220818131042.113280-7-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/mmzone.h | 3 +++ mm/memory-tiers.c | 40 +++++++++++++++++++++++++++++++++++----- 2 files changed, 38 insertions(+), 5 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 87347945270b..e335a492c2eb 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1246,6 +1246,9 @@ 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 ea57fc1f37ac..91fc0c324a1f 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -4,6 +4,7 @@ #include #include #include +#include #include #include "internal.h" @@ -141,12 +142,18 @@ 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 @@ -309,6 +316,8 @@ 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); @@ -320,24 +329,45 @@ static struct memory_tier *set_node_memory_tier(int node) memtype = node_memory_types[node].memtype; node_set(node, memtype->nodes); memtier = find_create_memory_tier(memtype); + if (!IS_ERR(memtier)) + rcu_assign_pointer(pgdat->memtier, memtier); return memtier; } static void destroy_memory_tier(struct memory_tier *memtier) { list_del(&memtier->list); + /* + * synchronize_rcu in clear_node_memory_tier makes sure + * we don't have rcu access to this memory tier. + */ kfree(memtier); } 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. + * This also enables us to free the destroyed memory tier + * with kfree instead of kfree_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].memtype; node_clear(node, memtype->nodes); if (nodes_empty(memtype->nodes)) { From b26ac6f3ba38fac83db2d72551e6d994d0e0516f Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 18 Aug 2022 18:40:39 +0530 Subject: [PATCH 07/11] mm/demotion: drop memtier from memtype Now that we track node-specific memtier in pg_data_t, we can drop memtier from memtype. Link: https://lkml.kernel.org/r/20220818131042.113280-8-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/memory-tiers.h | 1 - mm/memory-tiers.c | 16 +++++++++------- 2 files changed, 9 insertions(+), 8 deletions(-) diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index ce9c6bac6725..7ca52ad2789f 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -28,7 +28,6 @@ struct memory_dev_type { /* Nodes of same abstract distance */ nodemask_t nodes; struct kref kref; - struct memory_tier *memtier; }; #ifdef CONFIG_NUMA diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index 91fc0c324a1f..0e2bd32375d6 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -105,17 +105,22 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty lockdep_assert_held_once(&memory_tier_lock); + adistance = round_down(adistance, memtier_adistance_chunk_size); /* * If the memtype is already part of a memory tier, * just return that. */ - if (memtype->memtier) - return memtype->memtier; + if (!list_empty(&memtype->tier_sibiling)) { + list_for_each_entry(memtier, &memory_tiers, list) { + if (adistance == memtier->adistance_start) + return memtier; + } + WARN_ON(1); + return ERR_PTR(-EINVAL); + } - 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) { @@ -135,7 +140,6 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty list_add_tail(&new_memtier->list, &memtier->list); else list_add_tail(&new_memtier->list, &memory_tiers); - memtype->memtier = new_memtier; list_add(&memtype->tier_sibiling, &new_memtier->memory_types); return new_memtier; } @@ -372,7 +376,6 @@ static bool clear_node_memory_tier(int node) node_clear(node, memtype->nodes); if (nodes_empty(memtype->nodes)) { list_del_init(&memtype->tier_sibiling); - memtype->memtier = NULL; if (list_empty(&memtier->memory_types)) destroy_memory_tier(memtier); } @@ -400,7 +403,6 @@ struct memory_dev_type *alloc_memory_type(int adistance) memtype->adistance = adistance; INIT_LIST_HEAD(&memtype->tier_sibiling); memtype->nodes = NODE_MASK_NONE; - memtype->memtier = NULL; kref_init(&memtype->kref); return memtype; } From 32008027289239100d8d2876f50b15d92bde1855 Mon Sep 17 00:00:00 2001 From: Jagdish Gediya Date: Thu, 18 Aug 2022 18:40:40 +0530 Subject: [PATCH 08/11] mm/demotion: demote pages according to allocation fallback order 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. Link: https://lkml.kernel.org/r/20220818131042.113280-9-aneesh.kumar@linux.ibm.com Signed-off-by: Jagdish Gediya Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: SeongJae Park Signed-off-by: Andrew Morton --- 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 7ca52ad2789f..42791554b9b9 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -5,6 +5,7 @@ #include #include #include +#include /* * Each tier cover a abstrace distance chunk size of 128 */ @@ -38,11 +39,17 @@ 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 @@ -75,5 +82,10 @@ 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 0e2bd32375d6..45dd6fa4e2d1 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -4,7 +4,6 @@ #include #include #include -#include #include #include "internal.h" @@ -20,6 +19,8 @@ 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 { @@ -161,6 +162,24 @@ 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 @@ -208,10 +227,19 @@ 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 @@ -243,7 +271,7 @@ 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); @@ -291,6 +319,23 @@ 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 b7e9d8f8f649..809df16c7c0d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1533,21 +1533,34 @@ 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; - return alloc_migration_target(page, (unsigned long)&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; + + mtc->gfp_mask &= ~__GFP_THISNODE; + mtc->nmask = allowed_mask; + + return alloc_migration_target(page, (unsigned long)mtc); } /* @@ -1560,6 +1573,19 @@ 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; @@ -1567,10 +1593,12 @@ 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); From 467b171af881282fc627328e6c164f044a6df888 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 18 Aug 2022 18:40:41 +0530 Subject: [PATCH 09/11] mm/demotion: update node_is_toptier to work with memory tiers With memory tier 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(slower) memory tiers added we consider all memory tiers above a memory tier having CPU NUMA nodes as a top memory tier [sj@kernel.org: include missed header file, memory-tiers.h] Link: https://lkml.kernel.org/r/20220820190720.248704-1-sj@kernel.org [akpm@linux-foundation.org: mm/memory.c needs linux/memory-tiers.h] [aneesh.kumar@linux.ibm.com: make toptier_distance inclusive upper bound of toptiers] Link: https://lkml.kernel.org/r/20220830081457.118960-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20220818131042.113280-10-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/memory-tiers.h | 11 +++++++++ include/linux/node.h | 5 ---- kernel/sched/fair.c | 1 + mm/huge_memory.c | 1 + mm/memory-tiers.c | 47 ++++++++++++++++++++++++++++++++++++ mm/memory.c | 1 + mm/migrate.c | 1 + mm/mprotect.c | 1 + 8 files changed, 63 insertions(+), 5 deletions(-) diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index 42791554b9b9..965009aa01d7 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -40,6 +40,7 @@ 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) { @@ -50,6 +51,11 @@ 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 @@ -87,5 +93,10 @@ 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/kernel/sched/fair.c b/kernel/sched/fair.c index d642e9ff2829..0e3e08a093d4 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -40,6 +40,7 @@ #include #include +#include #include #include #include diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 949d7c325133..534d30cff9d7 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index 45dd6fa4e2d1..c82eb0111383 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -37,6 +37,7 @@ static LIST_HEAD(memory_tiers); static struct node_memory_type_map node_memory_types[MAX_NUMNODES]; static struct memory_dev_type *default_dram_type; #ifdef CONFIG_MIGRATION +static int top_tier_adistance; /* * node_demotion[] examples: * @@ -162,6 +163,31 @@ 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; @@ -319,6 +345,27 @@ 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 - 1; + 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/memory.c b/mm/memory.c index 63832dab15d3..cb955c0b7738 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -66,6 +66,7 @@ #include #include #include +#include #include #include #include diff --git a/mm/migrate.c b/mm/migrate.c index 2a2329bf7c1a..d74573c36573 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -50,6 +50,7 @@ #include #include #include +#include #include diff --git a/mm/mprotect.c b/mm/mprotect.c index ed013f836b4a..55ed4a889990 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include #include From 3e061d924fe9c7b487ca45935f92fcd414ce6f1a Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 18 Aug 2022 18:40:42 +0530 Subject: [PATCH 10/11] lib/nodemask: optimize node_random for nodemask with single NUMA node 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. A simple test as below before = rdtsc_ordered(); for (i= 0; i < 100; i++) { rand = node_random(&nmask); } after = rdtsc_ordered(); Without fix after - before : 16438 With fix after - before : 816 Link: https://lkml.kernel.org/r/20220818131042.113280-11-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: "Huang, Ying" Acked-by: Wei Xu Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Yang Shi Cc: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/nodemask.h | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h index 3a0eec9f2faa..e66742db741c 100644 --- a/include/linux/nodemask.h +++ b/include/linux/nodemask.h @@ -505,12 +505,21 @@ static inline int num_node_state(enum node_states state) static inline int node_random(const nodemask_t *maskp) { #if defined(CONFIG_NUMA) && (MAX_NUMNODES > 1) - 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; #else return 0; From 9832fb87834e2bd925d30020962c81b05948fa7b Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 30 Aug 2022 13:47:36 +0530 Subject: [PATCH 11/11] mm/demotion: expose memory tier details via sysfs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add /sys/devices/virtual/memory_tiering/ where all memory tier related details can be found. All allocated memory tiers will be listed there as /sys/devices/virtual/memory_tiering/memory_tierN/ The nodes which are part of a specific memory tier can be listed via /sys/devices/virtual/memory_tiering/memory_tierN/nodes A directory hierarchy looks like :/sys/devices/virtual/memory_tiering$ tree memory_tier4/ memory_tier4/ ├── nodes ├── subsystem -> ../../../../bus/memory_tiering └── uevent :/sys/devices/virtual/memory_tiering$ cat memory_tier4/nodes 0,2 [aneesh.kumar@linux.ibm.com: drop toptier_nodes from sysfs] Link: https://lkml.kernel.org/r/20220922102201.62168-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20220830081736.119281-1-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: "Huang, Ying" Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Wei Xu Cc: Yang Shi Signed-off-by: Andrew Morton --- .../ABI/testing/sysfs-kernel-mm-memory-tiers | 25 ++++ mm/memory-tiers.c | 109 ++++++++++++++---- 2 files changed, 112 insertions(+), 22 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers b/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers new file mode 100644 index 000000000000..45985e411f13 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers @@ -0,0 +1,25 @@ +What: /sys/devices/virtual/memory_tiering/ +Date: August 2022 +Contact: Linux memory management mailing list +Description: A collection of all the memory tiers allocated. + + Individual memory tier details are contained in subdirectories + named by the abstract distance of the memory tier. + + /sys/devices/virtual/memory_tiering/memory_tierN/ + + +What: /sys/devices/virtual/memory_tiering/memory_tierN/ + /sys/devices/virtual/memory_tiering/memory_tierN/nodes +Date: August 2022 +Contact: Linux memory management mailing list +Description: Directory with details of a specific memory tier + + This is the directory containing information about a particular + memory tier, memtierN, where N is derived based on abstract distance. + + A smaller value of N implies a higher (faster) memory tier in the + hierarchy. + + nodes: NUMA nodes that are part of this memory tier. + diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index c82eb0111383..f116b7b6333e 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -19,6 +19,7 @@ struct memory_tier { * adistance_start .. adistance_start + MEMTIER_CHUNK_SIZE */ int adistance_start; + struct device dev; /* All the nodes that are part of all the lower memory tiers. */ nodemask_t lower_tier_mask; }; @@ -36,6 +37,12 @@ static DEFINE_MUTEX(memory_tier_lock); static LIST_HEAD(memory_tiers); static struct node_memory_type_map node_memory_types[MAX_NUMNODES]; static struct memory_dev_type *default_dram_type; + +static struct bus_type memory_tier_subsys = { + .name = "memory_tiering", + .dev_name = "memory_tier", +}; + #ifdef CONFIG_MIGRATION static int top_tier_adistance; /* @@ -98,8 +105,63 @@ static int top_tier_adistance; static struct demotion_nodes *node_demotion __read_mostly; #endif /* CONFIG_MIGRATION */ +static inline struct memory_tier *to_memory_tier(struct device *device) +{ + return container_of(device, struct memory_tier, dev); +} + +static __always_inline nodemask_t get_memtier_nodemask(struct memory_tier *memtier) +{ + nodemask_t nodes = NODE_MASK_NONE; + struct memory_dev_type *memtype; + + list_for_each_entry(memtype, &memtier->memory_types, tier_sibiling) + nodes_or(nodes, nodes, memtype->nodes); + + return nodes; +} + +static void memory_tier_device_release(struct device *dev) +{ + struct memory_tier *tier = to_memory_tier(dev); + /* + * synchronize_rcu in clear_node_memory_tier makes sure + * we don't have rcu access to this memory tier. + */ + kfree(tier); +} + +static ssize_t nodes_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int ret; + nodemask_t nmask; + + mutex_lock(&memory_tier_lock); + nmask = get_memtier_nodemask(to_memory_tier(dev)); + ret = sysfs_emit(buf, "%*pbl\n", nodemask_pr_args(&nmask)); + mutex_unlock(&memory_tier_lock); + return ret; +} +static DEVICE_ATTR_RO(nodes); + +static struct attribute *memtier_dev_attrs[] = { + &dev_attr_nodes.attr, + NULL +}; + +static const struct attribute_group memtier_dev_group = { + .attrs = memtier_dev_attrs, +}; + +static const struct attribute_group *memtier_dev_groups[] = { + &memtier_dev_group, + NULL +}; + static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype) { + int ret; bool found_slot = false; struct memory_tier *memtier, *new_memtier; int adistance = memtype->adistance; @@ -123,15 +185,14 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty list_for_each_entry(memtier, &memory_tiers, list) { if (adistance == memtier->adistance_start) { - list_add(&memtype->tier_sibiling, &memtier->memory_types); - return memtier; + goto link_memtype; } else if (adistance < memtier->adistance_start) { found_slot = true; break; } } - new_memtier = kmalloc(sizeof(struct memory_tier), GFP_KERNEL); + new_memtier = kzalloc(sizeof(struct memory_tier), GFP_KERNEL); if (!new_memtier) return ERR_PTR(-ENOMEM); @@ -142,8 +203,23 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty list_add_tail(&new_memtier->list, &memtier->list); else list_add_tail(&new_memtier->list, &memory_tiers); - list_add(&memtype->tier_sibiling, &new_memtier->memory_types); - return new_memtier; + + new_memtier->dev.id = adistance >> MEMTIER_CHUNK_BITS; + new_memtier->dev.bus = &memory_tier_subsys; + new_memtier->dev.release = memory_tier_device_release; + new_memtier->dev.groups = memtier_dev_groups; + + ret = device_register(&new_memtier->dev); + if (ret) { + list_del(&memtier->list); + put_device(&memtier->dev); + return ERR_PTR(ret); + } + memtier = new_memtier; + +link_memtype: + list_add(&memtype->tier_sibiling, &memtier->memory_types); + return memtier; } static struct memory_tier *__node_get_memory_tier(int node) @@ -275,17 +351,6 @@ static void disable_all_demotion_targets(void) synchronize_rcu(); } -static __always_inline nodemask_t get_memtier_nodemask(struct memory_tier *memtier) -{ - nodemask_t nodes = NODE_MASK_NONE; - struct memory_dev_type *memtype; - - list_for_each_entry(memtype, &memtier->memory_types, tier_sibiling) - nodes_or(nodes, nodes, memtype->nodes); - - return nodes; -} - /* * Find an automatic demotion target for all memory * nodes. Failing here is OK. It might just indicate @@ -433,11 +498,7 @@ static struct memory_tier *set_node_memory_tier(int node) static void destroy_memory_tier(struct memory_tier *memtier) { list_del(&memtier->list); - /* - * synchronize_rcu in clear_node_memory_tier makes sure - * we don't have rcu access to this memory tier. - */ - kfree(memtier); + device_unregister(&memtier->dev); } static bool clear_node_memory_tier(int node) @@ -566,9 +627,13 @@ static int __meminit memtier_hotplug_callback(struct notifier_block *self, static int __init memory_tier_init(void) { - int node; + int ret, node; struct memory_tier *memtier; + ret = subsys_virtual_register(&memory_tier_subsys, NULL); + if (ret) + panic("%s() failed to register memory tier subsystem\n", __func__); + #ifdef CONFIG_MIGRATION node_demotion = kcalloc(nr_node_ids, sizeof(struct demotion_nodes), GFP_KERNEL);