[095/146] mm/page_isolation: unset migratetype directly for non Buddy page

Commit Message

Andrew Morton Jan. 14, 2022, 10:08 p.m. UTC

From: Chen Wandun <[e-mail]>
Subject: mm/page_isolation: unset migratetype directly for non Buddy page

In unset_migratetype_isolate(), we can bypass the call to
move_freepages_block() for non-buddy pages.

It will save a few cpu cycles for some situations such as cma and hugetlb
when allocating continue pages, in these situation function
alloc_contig_pages will be called.

alloc_contig_pages
	__alloc_contig_migrate_range
	isolate_freepages_range ==> pages has been remove from buddy
	undo_isolate_page_range
		unset_migratetype_isolate ==> can directly set migratetype

[[e-mail]: changelog tweak]
Link: https://lkml.kernel.org/r/[e-mail]
Fixes: 3c605096d315 ("mm/page_alloc: restrict max order of merging on isolated pageblock")
Signed-off-by: Chen Wandun <[e-mail]>
Reviewed-by: Oscar Salvador <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Cc: Joonsoo Kim <[e-mail]>
Cc: Wang Kefeng <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/page_isolation.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

--- a/mm/page_isolation.c~mm-page_isolation-unset-migratetype-directly-for-non-buddy-page
+++ a/mm/page_isolation.c
@@ -115,7 +115,7 @@  static void unset_migratetype_isolate(st
 	 * onlining - just onlined memory won't immediately be considered for
 	 * allocation.
 	 */
-	if (!isolated_page) {
+	if (!isolated_page && PageBuddy(page)) {
 		nr_pages = move_freepages_block(zone, page, migratetype, NULL);
 		__mod_zone_freepage_state(zone, nr_pages, migratetype);
 	}