From 633769c9267fadadffd31e27655bf028538238ad Mon Sep 17 00:00:00 2001
From: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Date: Thu, 18 May 2023 10:55:12 -0400
Subject: [PATCH] maple_tree: avoid unnecessary ascending
Git-commit: 633769c9267fadadffd31e27655bf028538238ad
Patch-mainline: v6.5-rc1
References: bsc#1219404
The maple tree node limits are implied by the parent. When walking up the
tree, the limit may not be known until a slot that does not have implied
limits are encountered. However, if the node is the left-most or
right-most node, the walking up to find that limit can be skipped.
This commit also fixes the debug/testing code that was not setting the
limit on walking down the tree as that optimization is not compatible with
this change.
Link: https://lkml.kernel.org/r/20230518145544.1722059-4-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
lib/maple_tree.c | 11 ++++++++---
tools/testing/radix-tree/maple.c | 4 ++++
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 0471215e5761..ccd834d624ed 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1103,7 +1103,6 @@ static int mas_ascend(struct ma_state *mas)
enum maple_type a_type;
unsigned long min, max;
unsigned long *pivots;
- unsigned char offset;
bool set_max = false, set_min = false;
a_node = mas_mn(mas);
@@ -1115,8 +1114,9 @@ static int mas_ascend(struct ma_state *mas)
p_node = mte_parent(mas->node);
if (unlikely(a_node == p_node))
return 1;
+
a_type = mas_parent_type(mas, mas->node);
- offset = mte_parent_slot(mas->node);
+ mas->offset = mte_parent_slot(mas->node);
a_enode = mt_mk_node(p_node, a_type);
/* Check to make sure all parent information is still accurate */
@@ -1124,7 +1124,6 @@ static int mas_ascend(struct ma_state *mas)
return 1;
mas->node = a_enode;
- mas->offset = offset;
if (mte_is_root(a_enode)) {
mas->max = ULONG_MAX;
@@ -1132,6 +1131,12 @@ static int mas_ascend(struct ma_state *mas)
return 0;
}
+ if (!mas->min)
+ set_min = true;
+
+ if (mas->max == ULONG_MAX)
+ set_max = true;
+
min = 0;
max = ULONG_MAX;
do {
diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c
index 9286d3baa12d..75df543e019c 100644
--- a/tools/testing/radix-tree/maple.c
+++ b/tools/testing/radix-tree/maple.c
@@ -35259,6 +35259,7 @@ static void mas_dfs_preorder(struct ma_state *mas)
struct maple_enode *prev;
unsigned char end, slot = 0;
+ unsigned long *pivots;
if (mas->node == MAS_START) {
mas_start(mas);
@@ -35291,6 +35292,9 @@ static void mas_dfs_preorder(struct ma_state *mas)
mas_ascend(mas);
goto walk_up;
}
+ pivots = ma_pivots(mte_to_node(prev), mte_node_type(prev));
+ mas->max = mas_safe_pivot(mas, pivots, slot, mte_node_type(prev));
+ mas->min = mas_safe_min(mas, pivots, slot);
return;
done:
--
2.35.3