From 6664bfc8e934dd008565510a41d86a552bd0bb00 Mon Sep 17 00:00:00 2001
From: Wei Yang <richard.weiyang@linux.alibaba.com>
Date: Tue, 13 Oct 2020 16:56:39 -0700
Subject: [PATCH] mm/hugetlb: take the free hpage during the iteration directly

Function dequeue_huge_page_node_exact() iterates the free list and return
the first valid free hpage.

Instead of break and check the loop variant, we could return in the loop
directly.  This could reduce some redundant check.

[mike.kravetz@oracle.com: points out a logic error]
[richard.weiyang@linux.alibaba.com: v4]
  Link: https://lkml.kernel.org/r/20200901014636.29737-8-richard.weiyang@linux.alibaba.com

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: https://lkml.kernel.org/r/20200831022351.20916-8-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/hugetlb.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a5068a38d8afb..cc70e541c9bf9 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1040,21 +1040,17 @@ static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
 		if (nocma && is_migrate_cma_page(page))
 			continue;
 
-		if (!PageHWPoison(page))
-			break;
+		if (PageHWPoison(page))
+			continue;
+
+		list_move(&page->lru, &h->hugepage_activelist);
+		set_page_refcounted(page);
+		h->free_huge_pages--;
+		h->free_huge_pages_node[nid]--;
+		return page;
 	}
 
-	/*
-	 * if 'non-isolated free hugepage' not found on the list,
-	 * the allocation fails.
-	 */
-	if (&h->hugepage_freelists[nid] == &page->lru)
-		return NULL;
-	list_move(&page->lru, &h->hugepage_activelist);
-	set_page_refcounted(page);
-	h->free_huge_pages--;
-	h->free_huge_pages_node[nid]--;
-	return page;
+	return NULL;
 }
 
 static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
-- 
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