[RFC PATCH 3/3] mm: Make free_area_init_node call certain functions only when booting

From: osalvador
Date: Tue Jul 17 2018 - 06:57:00 EST


From: Oscar Salvador <osalvador@xxxxxxx>

If free_area_init_node got called from memhotplug code, we do not need
to call calculate_node_totalpages(), as the node has no pages.

We do not need to set the range for the deferred initialization either,
as memmap_init_zone skips that when the context is MEMMAP_HOTPLUG.

Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
---
mm/page_alloc.c | 37 ++++++++++++++++++++++---------------
1 file changed, 22 insertions(+), 15 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3bf939393ca1..d2562751dbfd 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6299,8 +6299,6 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
spin_lock_init(&pgdat->lru_lock);
lruvec_init(node_lruvec(pgdat));

- pgdat->per_cpu_nodestats = &boot_nodestats;
-
for (j = 0; j < MAX_NR_ZONES; j++) {
struct zone *zone = pgdat->node_zones + j;

@@ -6386,6 +6384,21 @@ static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
static void __ref alloc_node_mem_map(struct pglist_data *pgdat) { }
#endif /* CONFIG_FLAT_NODE_MEM_MAP */

+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+static void pgdat_set_deferred_range(pg_data_t *pgdat)
+{
+ /*
+ * We start only with one section of pages, more pages are added as
+ * needed until the rest of deferred pages are initialized.
+ */
+ pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION,
+ pgdat->node_spanned_pages);
+ pgdat->first_deferred_pfn = ULONG_MAX;
+}
+#else
+static void pgdat_set_deferred_range(pg_data_t *pgdat) {}
+#endif
+
void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
unsigned long node_start_pfn, unsigned long *zholes_size)
{
@@ -6407,20 +6420,14 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
#else
start_pfn = node_start_pfn;
#endif
- calculate_node_totalpages(pgdat, start_pfn, end_pfn,
- zones_size, zholes_size);
-
- alloc_node_mem_map(pgdat);
+ if (system_state == SYSTEM_BOOTING) {
+ calculate_node_totalpages(pgdat, start_pfn, end_pfn,
+ zones_size, zholes_size);
+ alloc_node_mem_map(pgdat);
+ pgdat_set_deferred_range(pgdat);
+ pgdat->per_cpu_nodestats = &boot_nodestats;
+ }

-#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
- /*
- * We start only with one section of pages, more pages are added as
- * needed until the rest of deferred pages are initialized.
- */
- pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION,
- pgdat->node_spanned_pages);
- pgdat->first_deferred_pfn = ULONG_MAX;
-#endif
free_area_init_core(pgdat);
}

--
2.13.6