linux-kernel - [PATCH v2 2/2] mm/page_isolation: fixup isolate_single_pageblock() comment regarding splitting free pages

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Message-ID: <20241210102953.218122-3-david@redhat.com>
Date: Tue, 10 Dec 2024 11:29:53 +0100
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org,
	David Hildenbrand <david@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Zi Yan <ziy@...dia.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	Yu Zhao <yuzhao@...gle.com>
Subject: [PATCH v2 2/2] mm/page_isolation: fixup isolate_single_pageblock() comment regarding splitting free pages

Let's fixup the comment, documenting how free_one_page_maybe_split()
comes into play.

Reviewed-by: Zi Yan <ziy@...dia.com>
Acked-by: Vlastimil Babka <vbabka@...e.cz>
Signed-off-by: David Hildenbrand <david@...hat.com>
---
 mm/page_isolation.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index c608e9d728655..63fddf283e681 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -298,11 +298,10 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
  * pagelbocks.
  * [      MAX_PAGE_ORDER         ]
  * [  pageblock0  |  pageblock1  ]
- * When either pageblock is isolated, if it is a free page, the page is not
- * split into separate migratetype lists, which is supposed to; if it is an
- * in-use page and freed later, __free_one_page() does not split the free page
- * either. The function handles this by splitting the free page or migrating
- * the in-use page then splitting the free page.
+ * When either pageblock is isolated, if it is an in-use page and freed later,
+ * __free_one_page_maybe_split() will split the free page if required. If the
+ * page is already free, this function handles this by splitting the free page
+ * through move_freepages_block_isolate()->__free_one_page_maybe_split().
  */
 static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
 		bool isolate_before, bool skip_isolation, int migratetype)
-- 
2.47.1