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From: Wei Yang <richard.weiyang@gmail.com>
To: akpm@linux-foundation.org, Liam.Howlett@oracle.com
Cc: maple-tree@lists.infradead.org, linux-mm@kvack.org,
	Wei Yang <richard.weiyang@gmail.com>
Subject: [PATCH 2/2] maple_tree: goto complete directly on a pivot of 0
Date: Wed, 11 Sep 2024 14:27:59 +0000	[thread overview]
Message-ID: <20240911142759.20989-3-richard.weiyang@gmail.com> (raw)
In-Reply-To: <20240911142759.20989-1-richard.weiyang@gmail.com>

When we break the loop after assigning a pivot, the index i/j is not
changed. Then the following code assign pivot, which means we do the
assignment with same i/j by mas_safe_pivot.

Since the loop condition is (i < piv_end), from which we can get i is
less than mt_pivots[mt]. It implies mas_safe_pivot() return pivot[i]
which is the same value we get in loop.

Now we can conclude it does a redundant assignment on a pivot of 0.
Let's just go to complete to avoid it.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
 lib/maple_tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 6fd62b7ef240..f7bb3f686548 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1942,7 +1942,7 @@ static inline void mas_mab_cp(struct ma_state *mas, unsigned char mas_start,
 	for (; i < piv_end; i++, j++) {
 		b_node->pivot[j] = pivots[i];
 		if (unlikely(!b_node->pivot[j]))
-			break;
+			goto complete;
 
 		if (unlikely(mas->max == b_node->pivot[j]))
 			goto complete;
-- 
2.34.1



  parent reply	other threads:[~2024-09-11 14:34 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-11 14:27 [PATCH 0/2] refine mas_mab_cp() Wei Yang
2024-09-11 14:27 ` [PATCH 1/2] maple_tree: i is always less than or equal to mas_end Wei Yang
2024-09-11 15:26   ` Liam R. Howlett
2024-09-11 14:27 ` Wei Yang [this message]
2024-09-11 15:26   ` [PATCH 2/2] maple_tree: goto complete directly on a pivot of 0 Liam R. Howlett

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