diff options
author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2022-08-18 18:40:37 +0530 |
---|---|---|
committer | Andrew Morton <akpm@linux-foundation.org> | 2022-09-26 19:46:12 -0700 |
commit | 6c542ab75714fe90dae292aeb3e91ac53f5ff599 (patch) | |
tree | ddc14072be56d9171f8038436cf2045a5992e842 /mm/memory-tiers.c | |
parent | 7b88bda3761b95856cf97822efe8281c8100067b (diff) |
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 <aneesh.kumar@linux.ibm.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Wei Xu <weixugc@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Bharata B Rao <bharata@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hesham Almatary <hesham.almatary@huawei.com>
Cc: Jagdish Gediya <jvgediya.oss@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/memory-tiers.c')
-rw-r--r-- | mm/memory-tiers.c | 238 |
1 files changed, 226 insertions, 12 deletions
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 <linux/memory.h> #include <linux/memory-tiers.h> +#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 = <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) { @@ -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); |