linux-kernel - [PATCH 2/3] mm/page_ext: remove rollback for untouched mem_section in online_page

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Message-Id: <20230714114749.1743032-3-shikemeng@huaweicloud.com>
Date:   Fri, 14 Jul 2023 19:47:48 +0800
From:   Kemeng Shi <shikemeng@...weicloud.com>
To:     akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Cc:     shikemeng@...weicloud.com
Subject: [PATCH 2/3] mm/page_ext: remove rollback for untouched mem_section in online_page_ext

If init_section_page_ext failed, we only need rollback for mem_section
before failed mem_section. Make rollback end point to failed mem_section
to remove unnecessary rollback.

As pfn += PAGES_PER_SECTION will be executed even if init_section_page_ext
failed. So pfn points to mem_section after failed mem_section. Subtract
one mem_section from pfn to get failed mem_section.

Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
---
 mm/page_ext.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/page_ext.c b/mm/page_ext.c
index 096451df1c87..f052397dc70f 100644
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -424,6 +424,7 @@ static int __meminit online_page_ext(unsigned long start_pfn,
 		return 0;

 	/* rollback */
+	end = pfn - PAGES_PER_SECTION;
 	for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
 		__free_page_ext(pfn);

-- 
2.30.0