linux-kernel - [PATCH 6.6 19/28] maple_tree: mtree_range

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20241024132225.2271667-4-yukuai1@huaweicloud.com>
Date: Thu, 24 Oct 2024 21:22:16 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: stable@...r.kernel.org,
	gregkh@...uxfoundation.org,
	harry.wentland@....com,
	sunpeng.li@....com,
	Rodrigo.Siqueira@....com,
	alexander.deucher@....com,
	christian.koenig@....com,
	Xinhui.Pan@....com,
	airlied@...il.com,
	daniel@...ll.ch,
	viro@...iv.linux.org.uk,
	brauner@...nel.org,
	Liam.Howlett@...cle.com,
	akpm@...ux-foundation.org,
	hughd@...gle.com,
	willy@...radead.org,
	sashal@...nel.org,
	srinivasan.shanmugam@....com,
	chiahsuan.chung@....com,
	mingo@...nel.org,
	mgorman@...hsingularity.net,
	yukuai3@...wei.com,
	chengming.zhou@...ux.dev,
	zhangpeng.00@...edance.com,
	chuck.lever@...cle.com
Cc: amd-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org,
	maple-tree@...ts.infradead.org,
	linux-mm@...ck.org,
	yukuai1@...weicloud.com,
	yi.zhang@...wei.com,
	yangerkun@...wei.com
Subject: [PATCH 6.6 19/28] maple_tree: mtree_range_walk() clean up

From: "Liam R. Howlett" <Liam.Howlett@...cle.com>

commit a3c63c8c5df6406e79490456a1fc41a287676070 upstream.

mtree_range_walk() needed to be updated to avoid checking if there was a
pivot value.  On closer examination, the code could avoid setting min or
max in certain scenarios.  The commit removes the extra check for
pivot[offset] before setting max and only sets max when necessary.  It
also only sets min if it is necessary by checking offset 0 prior to the
loop (as it has always done).

The commit also drops a dead node check since the end of the node will
return the array size when the last slot is occupied (by a potential reuse
in a dead node).  The data will be discarded later if the node is marked
dead.

Benchmarking these changes results in an increase in performance of 5.45%
using the BENCH_WALK in the maple tree test code.

Link: https://lkml.kernel.org/r/20231101171629.3612299-13-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
Cc: Peng Zhang <zhangpeng.00@...edance.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Yu Kuai <yukuai3@...wei.com>
---
 lib/maple_tree.c | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index ad8bf3413889..d90f4b7e7511 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -2806,32 +2806,29 @@ static inline void *mtree_range_walk(struct ma_state *mas)
 	min = mas->min;
 	max = mas->max;
 	do {
-		offset = 0;
 		last = next;
 		node = mte_to_node(next);
 		type = mte_node_type(next);
 		pivots = ma_pivots(node, type);
 		end = ma_data_end(node, type, pivots, max);
-		if (unlikely(ma_dead_node(node)))
-			goto dead_node;
-
-		if (pivots[offset] >= mas->index) {
-			prev_max = max;
-			prev_min = min;
-			max = pivots[offset];
+		prev_min = min;
+		prev_max = max;
+		if (pivots[0] >= mas->index) {
+			offset = 0;
+			max = pivots[0];
 			goto next;
 		}
 
-		do {
+		offset = 1;
+		while (offset < end) {
+			if (pivots[offset] >= mas->index) {
+				max = pivots[offset];
+				break;
+			}
 			offset++;
-		} while ((offset < end) && (pivots[offset] < mas->index));
+		}
 
-		prev_min = min;
 		min = pivots[offset - 1] + 1;
-		prev_max = max;
-		if (likely(offset < end && pivots[offset]))
-			max = pivots[offset];
-
 next:
 		slots = ma_slots(node, type);
 		next = mt_slot(mas->tree, slots, offset);
-- 
2.39.2