linux-kernel - [Patch v2 7/7] mm/hugetlb: narrow the hugetlb_lock protection area during preparing huge page

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Date:   Fri, 28 Aug 2020 11:32:42 +0800
From:   Wei Yang <richard.weiyang@...ux.alibaba.com>
To:     mike.kravetz@...cle.com, akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org, bhe@...hat.com,
        Wei Yang <richard.weiyang@...ux.alibaba.com>
Subject: [Patch v2 7/7] mm/hugetlb: narrow the hugetlb_lock protection area during preparing huge page

set_hugetlb_cgroup_[rsvd] just manipulate page local data, which is not
necessary to be protected by hugetlb_lock.

Let's take this out.

Signed-off-by: Wei Yang <richard.weiyang@...ux.alibaba.com>
Reviewed-by: Baoquan He <bhe@...hat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@...cle.com>
---
 mm/hugetlb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6ad365dd1e96..ae840dc09197 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1492,9 +1492,9 @@ static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
 {
 	INIT_LIST_HEAD(&page->lru);
 	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
-	spin_lock(&hugetlb_lock);
 	set_hugetlb_cgroup(page, NULL);
 	set_hugetlb_cgroup_rsvd(page, NULL);
+	spin_lock(&hugetlb_lock);
 	h->nr_huge_pages++;
 	h->nr_huge_pages_node[nid]++;
 	spin_unlock(&hugetlb_lock);
-- 
2.20.1 (Apple Git-117)