2023-08-20 17:08:44

by Baolin Wang

[permalink] [raw]
Subject: [PATCH 2/4] mm: migrate: move the numamigrate_isolate_page() into do_numa_page()

Move the numamigrate_isolate_page() into do_numa_page() to simplify the
migrate_misplaced_page(), which now only focuses on page migration, and
it also serves as a preparation for supporting batch migration for NUMA
balancing.

Signed-off-by: Baolin Wang <[email protected]>
---
include/linux/migrate.h | 6 ++++++
mm/huge_memory.c | 10 ++++++++++
mm/memory.c | 10 ++++++++++
mm/migrate.c | 16 ++++------------
4 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 711dd9412561..7c5189043707 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -144,12 +144,18 @@ const struct movable_operations *page_movable_ops(struct page *page)
#ifdef CONFIG_NUMA_BALANCING
int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
int node);
+int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page);
#else
static inline int migrate_misplaced_page(struct page *page,
struct vm_area_struct *vma, int node)
{
return -EAGAIN; /* can't migrate now */
}
+
+static inline int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
+{
+ return -EAGAIN;
+}
#endif /* CONFIG_NUMA_BALANCING */

#ifdef CONFIG_MIGRATION
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index cb4432792b88..b7cc6828ce9e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1496,6 +1496,8 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK);
bool migrated = false, writable = false;
int flags = 0;
+ pg_data_t *pgdat;
+ int isolated;

vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) {
@@ -1540,11 +1542,19 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
spin_unlock(vmf->ptl);
writable = false;

+ pgdat = NODE_DATA(target_nid);
+ isolated = numamigrate_isolate_page(pgdat, page);
+ if (!isolated) {
+ put_page(page);
+ goto isolate_fail;
+ }
+
migrated = migrate_misplaced_page(page, vma, target_nid);
if (migrated) {
flags |= TNF_MIGRATED;
page_nid = target_nid;
} else {
+isolate_fail:
flags |= TNF_MIGRATE_FAIL;
vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) {
diff --git a/mm/memory.c b/mm/memory.c
index bee9b1e86ef0..01b1980d4fb7 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4779,6 +4779,8 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
int target_nid;
pte_t pte, old_pte;
int flags = 0;
+ pg_data_t *pgdat;
+ int isolated;

/*
* The "pte" at this point cannot be used safely without
@@ -4849,11 +4851,19 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
pte_unmap_unlock(vmf->pte, vmf->ptl);
writable = false;

+ pgdat = NODE_DATA(target_nid);
+ isolated = numamigrate_isolate_page(pgdat, page);
+ if (!isolated) {
+ put_page(page);
+ goto isolate_fail;
+ }
+
/* Migrate to the requested node */
if (migrate_misplaced_page(page, vma, target_nid)) {
page_nid = target_nid;
flags |= TNF_MIGRATED;
} else {
+isolate_fail:
flags |= TNF_MIGRATE_FAIL;
vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
vmf->address, &vmf->ptl);
diff --git a/mm/migrate.c b/mm/migrate.c
index 9cc98fb1d6ec..5eeeb2cda21c 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2478,7 +2478,7 @@ static struct folio *alloc_misplaced_dst_folio(struct folio *src,
return __folio_alloc_node(gfp, order, nid);
}

-static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
+int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
{
int nr_pages = thp_nr_pages(page);
int order = compound_order(page);
@@ -2523,16 +2523,12 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
int node)
{
pg_data_t *pgdat = NODE_DATA(node);
- int isolated;
+ int migrated = 1;
int nr_remaining;
unsigned int nr_succeeded;
LIST_HEAD(migratepages);
int nr_pages = thp_nr_pages(page);

- isolated = numamigrate_isolate_page(pgdat, page);
- if (!isolated)
- goto out;
-
list_add(&page->lru, &migratepages);
nr_remaining = migrate_pages(&migratepages, alloc_misplaced_dst_folio,
NULL, node, MIGRATE_ASYNC,
@@ -2544,7 +2540,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
page_is_file_lru(page), -nr_pages);
putback_lru_page(page);
}
- isolated = 0;
+ migrated = 0;
}
if (nr_succeeded) {
count_vm_numa_events(NUMA_PAGE_MIGRATE, nr_succeeded);
@@ -2553,11 +2549,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
nr_succeeded);
}
BUG_ON(!list_empty(&migratepages));
- return isolated;
-
-out:
- put_page(page);
- return 0;
+ return migrated;
}
#endif /* CONFIG_NUMA_BALANCING */
#endif /* CONFIG_NUMA */
--
2.39.3