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-rw-r--r--mm/memory-tiers.c51
-rw-r--r--mm/vmscan.c58
2 files changed, 91 insertions, 18 deletions
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 <linux/sysfs.h>
#include <linux/kobject.h>
#include <linux/memory.h>
-#include <linux/mmzone.h>
#include <linux/memory-tiers.h>
#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;
+
+ mtc = (struct migration_target_control *)private;
+
+ allowed_mask = mtc->nmask;
+ /*
+ * make sure we allocate from the target node first also trying to
+ * demote or reclaim pages from the target node via kswapd if we are
+ * low on free memory on target node. If we don't do this and if
+ * we have free memory on the slower(lower) memtier, we would start
+ * allocating pages from slower(lower) memory tiers without even forcing
+ * a demotion of cold pages from the target memtier. This can result
+ * in the kernel placing hot pages in slower(lower) memory tiers.
+ */
+ mtc->nmask = NULL;
+ mtc->gfp_mask |= __GFP_THISNODE;
+ target_page = alloc_migration_target(page, (unsigned long)mtc);
+ if (target_page)
+ return target_page;
- return alloc_migration_target(page, (unsigned long)&mtc);
+ mtc->gfp_mask &= ~__GFP_THISNODE;
+ mtc->nmask = allowed_mask;
+
+ return alloc_migration_target(page, (unsigned long)mtc);
}
/*
@@ -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);