mm: meminit: minimise number of pfn->page lookups during initialisation
Deferred struct page initialisation is using pfn_to_page() on every PFN
unnecessarily. This patch minimises the number of lookups and scheduler
checks.
Signed-off-by: Mel Gorman <[email protected]>
Tested-by: Nate Zimmer <[email protected]>
Tested-by: Waiman Long <[email protected]>
Tested-by: Daniel J Blueman <[email protected]>
Acked-by: Pekka Enberg <[email protected]>
Cc: Robin Holt <[email protected]>
Cc: Nate Zimmer <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Waiman Long <[email protected]>
Cc: Scott Norton <[email protected]>
Cc: "Luck, Tony" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c30f5a0..0f770cc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1091,6 +1091,7 @@
for_each_mem_pfn_range(i, nid, &walk_start, &walk_end, NULL) {
unsigned long pfn, end_pfn;
+ struct page *page = NULL;
end_pfn = min(walk_end, zone_end_pfn(zone));
pfn = first_init_pfn;
@@ -1100,13 +1101,32 @@
pfn = zone->zone_start_pfn;
for (; pfn < end_pfn; pfn++) {
- struct page *page;
-
- if (!pfn_valid(pfn))
+ if (!pfn_valid_within(pfn))
continue;
- if (!meminit_pfn_in_nid(pfn, nid, &nid_init_state))
+ /*
+ * Ensure pfn_valid is checked every
+ * MAX_ORDER_NR_PAGES for memory holes
+ */
+ if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) {
+ if (!pfn_valid(pfn)) {
+ page = NULL;
+ continue;
+ }
+ }
+
+ if (!meminit_pfn_in_nid(pfn, nid, &nid_init_state)) {
+ page = NULL;
continue;
+ }
+
+ /* Minimise pfn page lookups and scheduler checks */
+ if (page && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) {
+ page++;
+ } else {
+ page = pfn_to_page(pfn);
+ cond_resched();
+ }
if (page->flags) {
VM_BUG_ON(page_zone(page) != zone);
@@ -1116,7 +1136,6 @@
__init_single_page(page, pfn, zid, nid);
__free_pages_boot_core(page, pfn, 0);
nr_pages++;
- cond_resched();
}
first_init_pfn = max(end_pfn, first_init_pfn);
}
