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>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a5068a3..cc70e54 100644 (file)
--- 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,