linux-kernel - [PATCH 1/1] memblock cleanup: Remove unnecessary check in memblock_find_in_range

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Date:	Thu, 15 Aug 2013 11:23:19 +0800
From:	Tang Chen <tangchen@...fujitsu.com>
To:	mingo@...hat.com, hpa@...or.com, akpm@...ux-foundation.org,
	liwanp@...ux.vnet.ibm.com, tj@...nel.org
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/1] memblock cleanup: Remove unnecessary check in memblock_find_in_range_node()

In memblock_find_in_range_node(), it has the following check at line 117 and 118:

 113         for_each_free_mem_range_reverse(i, nid, &this_start, &this_end, NULL) {
 114                 this_start = clamp(this_start, start, end);
 115                 this_end = clamp(this_end, start, end);
 116
 117                 if (this_end < size)
 118                         continue;
 119
 120                 cand = round_down(this_end - size, align);
 121                 if (cand >= this_start)
 122                         return cand;
 123         }

Since it finds memory from higher memory downwards, if this_end < size,
we can break because the rest memory will all under size. It won't satisfy
us ang more.

Furthermore, we don't need to check "if (this_end < size)" actually. Without
this confusing check, we only waste some loops. So this patch removes the
check.

Signed-off-by: Tang Chen <tangchen@...fujitsu.com>
---
 mm/memblock.c |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/mm/memblock.c b/mm/memblock.c
index a847bfe..e0c626e 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -114,9 +114,6 @@ phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t start,
 		this_start = clamp(this_start, start, end);
 		this_end = clamp(this_end, start, end);
 
-		if (this_end < size)
-			continue;
-
 		cand = round_down(this_end - size, align);
 		if (cand >= this_start)
 			return cand;
-- 
1.7.1

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