linux-kernel - [PATCH 4/4] mm: don't set page count in deferred_init

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Date:   Fri, 22 Sep 2023 15:09:23 +0800
From:   Yajun Deng <yajun.deng@...ux.dev>
To:     akpm@...ux-foundation.org, mike.kravetz@...cle.com,
        muchun.song@...ux.dev, glider@...gle.com, elver@...gle.com,
        dvyukov@...gle.com, rppt@...nel.org, david@...hat.com,
        osalvador@...e.de
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        kasan-dev@...glegroups.com, Yajun Deng <yajun.deng@...ux.dev>
Subject: [PATCH 4/4] mm: don't set page count in deferred_init_pages

The operations of page count in deferred_init_pages and deferred_free_range
is the opposite operation. It's unnecessary and time-consuming.

Don't set page count in deferred_init_pages, as it'll be reset later.

The following data was tested on an x86 machine with 190GB of RAM.

before:
node 0 deferred pages initialised in 78ms

after:
node 0 deferred pages initialised in 72ms

Signed-off-by: Yajun Deng <yajun.deng@...ux.dev>
---
 mm/mm_init.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 1cc310f706a9..fe78f6916c66 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -1984,7 +1984,7 @@ static void __init deferred_free_range(unsigned long pfn,
 	if (nr_pages == MAX_ORDER_NR_PAGES && IS_MAX_ORDER_ALIGNED(pfn)) {
 		for (i = 0; i < nr_pages; i += pageblock_nr_pages)
 			set_pageblock_migratetype(page + i, MIGRATE_MOVABLE);
-		__free_pages_core(page, MAX_ORDER, MEMINIT_LATE);
+		__free_pages_core(page, MAX_ORDER, MEMINIT_EARLY);
 		return;
 	}
 
@@ -1994,7 +1994,7 @@ static void __init deferred_free_range(unsigned long pfn,
 	for (i = 0; i < nr_pages; i++, page++, pfn++) {
 		if (pageblock_aligned(pfn))
 			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
-		__free_pages_core(page, 0, MEMINIT_LATE);
+		__free_pages_core(page, 0, MEMINIT_EARLY);
 	}
 }
 
@@ -2068,7 +2068,7 @@ static unsigned long  __init deferred_init_pages(struct zone *zone,
 		} else {
 			page++;
 		}
-		__init_single_page(page, pfn, zid, nid, true, false);
+		__init_single_page(page, pfn, zid, nid, false, false);
 		nr_pages++;
 	}
 	return (nr_pages);
-- 
2.25.1