linux-kernel - [PATCH 10/10] mm/hugetlb: not necessary to abuse temporary page to workaround the nasty free_huge

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Date:   Fri,  7 Aug 2020 17:12:51 +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,
        Wei Yang <richard.weiyang@...ux.alibaba.com>
Subject: [PATCH 10/10] mm/hugetlb: not necessary to abuse temporary page to workaround the nasty free_huge_page

Let's always increase surplus_huge_pages and so that free_huge_page
could decrease it at free time.

Signed-off-by: Wei Yang <richard.weiyang@...ux.alibaba.com>
---
 mm/hugetlb.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 1f2010c9dd8d..a0eb81e0e4c5 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1913,21 +1913,19 @@ static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
 		return NULL;
 
 	spin_lock(&hugetlb_lock);
+
+	h->surplus_huge_pages++;
+	h->surplus_huge_pages_node[page_to_nid(page)]++;
+
 	/*
 	 * We could have raced with the pool size change.
 	 * Double check that and simply deallocate the new page
-	 * if we would end up overcommiting the surpluses. Abuse
-	 * temporary page to workaround the nasty free_huge_page
-	 * codeflow
+	 * if we would end up overcommiting the surpluses.
 	 */
-	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
-		SetPageHugeTemporary(page);
+	if (h->surplus_huge_pages > h->nr_overcommit_huge_pages) {
 		spin_unlock(&hugetlb_lock);
 		put_page(page);
 		return NULL;
-	} else {
-		h->surplus_huge_pages++;
-		h->surplus_huge_pages_node[page_to_nid(page)]++;
 	}
 
 out_unlock:
-- 
2.20.1 (Apple Git-117)