linux-kernel - [PATCH v3 12/16] mm/huge_memory: minor cleanup for split_huge_pages

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Message-ID: <20220704132201.14611-13-linmiaohe@huawei.com>
Date:   Mon, 4 Jul 2022 21:21:57 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>
CC:     <shy828301@...il.com>, <willy@...radead.org>, <zokeefe@...gle.com>,
        <songmuchun@...edance.com>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>, <linmiaohe@...wei.com>
Subject: [PATCH v3 12/16] mm/huge_memory: minor cleanup for split_huge_pages_all

There is nothing to do if a zone doesn't have any pages managed by the
buddy allocator. So we should check managed_zone instead. Also if a thp
is found, there's no need to traverse the subpages again.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 mm/huge_memory.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 6d95751ebfc9..77be7dec1420 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2961,9 +2961,12 @@ static void split_huge_pages_all(void)
 	unsigned long total = 0, split = 0;
 
 	pr_debug("Split all THPs\n");
-	for_each_populated_zone(zone) {
+	for_each_zone(zone) {
+		if (!managed_zone(zone))
+			continue;
 		max_zone_pfn = zone_end_pfn(zone);
 		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) {
+			int nr_pages;
 			if (!pfn_valid(pfn))
 				continue;
 
@@ -2979,8 +2982,10 @@ static void split_huge_pages_all(void)
 
 			total++;
 			lock_page(page);
+			nr_pages = thp_nr_pages(page);
 			if (!split_huge_page(page))
 				split++;
+			pfn += nr_pages - 1;
 			unlock_page(page);
 next:
 			put_page(page);
-- 
2.23.0