[PATCH v3 16/21] mm/mm_init: init deferred page migratetype in deferred_init_pages()

[Pratyush Yadav]

From: "Pratyush Yadav (Google)" <pratyush@xxxxxxxxxx>

The deferred pages are initialized in deferred_init_pages(), but their
migratetype is initialized later when freeing them in
deferred_free_pages(). Setting the migrate type is part of initializing
the pages, so move it to deferred_init_pages().

This simplifies the logic in deferred_free_pages(), which now only does
the freeing. For non-max-order-aligned pages, it also drops the
if (pageblock_aligned) for each freed page, which in theory should be a
tiny bit faster.

Another motivation for this change is that in a coming patch, KHO will
need to update the migrate type for its scratch pages. Moving all the
pageblock init in one place makes that simpler.

Signed-off-by: Pratyush Yadav (Google) <pratyush@xxxxxxxxxx>
---
 mm/mm_init.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 84d4b1c997bc..bd9dc1829005 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -1985,8 +1985,6 @@ static void __init deferred_free_pages(unsigned long pfn,
 
 	/* Free a large naturally-aligned chunk if possible */
 	if (nr_pages == MAX_ORDER_NR_PAGES && IS_MAX_ORDER_ALIGNED(pfn)) {
-		for (i = 0; i < nr_pages; i += pageblock_nr_pages)
-			init_pageblock_migratetype(page + i, mt, false);
 		__free_pages_core(page, MAX_PAGE_ORDER, MEMINIT_EARLY);
 		return;
 	}
@@ -1994,11 +1992,8 @@ static void __init deferred_free_pages(unsigned long pfn,
 	/* Accept chunks smaller than MAX_PAGE_ORDER upfront */
 	accept_memory(PFN_PHYS(pfn), nr_pages * PAGE_SIZE);
 
-	for (i = 0; i < nr_pages; i++, page++, pfn++) {
-		if (pageblock_aligned(pfn))
-			init_pageblock_migratetype(page, mt, false);
+	for (i = 0; i < nr_pages; i++, page++, pfn++)
 		__free_pages_core(page, 0, MEMINIT_EARLY);
-	}
 }
 
 /* Completion tracking for deferred_init_memmap() threads */
@@ -2017,15 +2012,23 @@ static inline void __init pgdat_init_report_one_done(void)
  * Return number of pages initialized.
  */
 static unsigned long __init deferred_init_pages(struct zone *zone,
-		unsigned long pfn, unsigned long end_pfn)
+		unsigned long start_pfn, unsigned long end_pfn,
+		enum migratetype mt)
 {
 	int nid = zone_to_nid(zone);
-	unsigned long nr_pages = end_pfn - pfn;
+	unsigned long nr_pages = end_pfn - start_pfn, pfn = start_pfn;
 	int zid = zone_idx(zone);
 	struct page *page = pfn_to_page(pfn);
 
 	for (; pfn < end_pfn; pfn++, page++)
 		__init_single_page(page, pfn, zid, nid);
+
+	/* Now initialize migrate types for these pages. */
+	pfn = pageblock_align(start_pfn);
+	page = pfn_to_page(pfn);
+	for (; pfn < end_pfn; pfn += pageblock_nr_pages, page += pageblock_nr_pages)
+		init_pageblock_migratetype(page, mt, false);
+
 	return nr_pages;
 }
 
@@ -2067,7 +2070,7 @@ deferred_init_memmap_chunk(unsigned long start_pfn, unsigned long end_pfn,
 			unsigned long mo_pfn = ALIGN(spfn + 1, MAX_ORDER_NR_PAGES);
 			unsigned long chunk_end = min(mo_pfn, epfn);
 
-			nr_pages += deferred_init_pages(zone, spfn, chunk_end);
+			nr_pages += deferred_init_pages(zone, spfn, chunk_end, mt);
 			deferred_free_pages(spfn, chunk_end - spfn, mt);
 
 			spfn = chunk_end;
-- 
2.55.0.141.g00534a21ce-goog