The patch titled
Subject: maple_tree: avoid unnecessary ascending
has been added to the -mm mm-unstable branch. Its filename is
maple_tree-avoid-unnecessary-ascending.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-avoid-unnecessary-ascending.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: maple_tree: avoid unnecessary ascending
Date: Fri, 12 May 2023 14:20:04 -0400
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/20230512182036.359030-4-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reviewed-by: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx>
Cc: David Binderman <dcb314@xxxxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Vernon Yang <vernon2gm@xxxxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/maple_tree.c | 11 ++++++++---
tools/testing/radix-tree/maple.c | 4 ++++
2 files changed, 12 insertions(+), 3 deletions(-)
--- a/lib/maple_tree.c~maple_tree-avoid-unnecessary-ascending
+++ a/lib/maple_tree.c
@@ -1103,7 +1103,6 @@ static int mas_ascend(struct ma_state *m
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 *m
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 *m
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 *m
return 0;
}
+ if (!mas->min)
+ set_min = true;
+
+ if (mas->max == ULONG_MAX)
+ set_max = true;
+
min = 0;
max = ULONG_MAX;
do {
--- a/tools/testing/radix-tree/maple.c~maple_tree-avoid-unnecessary-ascending
+++ a/tools/testing/radix-tree/maple.c
@@ -35259,6 +35259,7 @@ static void mas_dfs_preorder(struct ma_s
struct maple_enode *prev;
unsigned char end, slot = 0;
+ unsigned long *pivots;
if (mas->node == MAS_START) {
mas_start(mas);
@@ -35291,6 +35292,9 @@ walk_up:
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:
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
maple_tree-fix-static-analyser-cppcheck-issue.patch
maple_tree-avoid-unnecessary-ascending.patch
maple_tree-clean-up-mas_dfs_postorder.patch
maple_tree-add-debug-bug_on-and-warn_on-variants.patch
maple_tree-use-mas_bug_on-when-setting-a-leaf-node-as-a-parent.patch
maple_tree-use-mas_bug_on-in-mas_set_height.patch
maple_tree-use-mas_bug_on-from-mas_topiary_range.patch
maple_tree-use-mas_wr_bug_on-in-mas_store_prealloc.patch
maple_tree-use-mas_bug_on-prior-to-calling-mas_meta_gap.patch
maple_tree-return-error-on-mte_pivots-out-of-range.patch
maple_tree-make-test-code-work-without-debug-enabled.patch
mm-update-validate_mm-to-use-vma-iterator.patch
mm-update-vma_iter_store-to-use-mas_warn_on.patch
maple_tree-add-__init-and-__exit-to-test-module.patch
maple_tree-remove-unnecessary-check-from-mas_destroy.patch
maple_tree-mas_start-reset-depth-on-dead-node.patch
mm-mmap-change-do_vmi_align_munmap-for-maple-tree-iterator-changes.patch
maple_tree-try-harder-to-keep-active-node-after-mas_next.patch
maple_tree-try-harder-to-keep-active-node-with-mas_prev.patch
maple_tree-revise-limit-checks-in-mas_empty_area_rev.patch
maple_tree-fix-testing-mas_empty_area.patch
maple_tree-introduce-mas_next_slot-interface.patch
maple_tree-add-mas_next_range-and-mas_find_range-interfaces.patch
maple_tree-relocate-mas_rewalk-and-mas_rewalk_if_dead.patch
maple_tree-introduce-mas_prev_slot-interface.patch
maple_tree-add-mas_prev_range-and-mas_find_range_rev-interface.patch
maple_tree-clear-up-index-and-last-setting-in-single-entry-tree.patch
maple_tree-update-testing-code-for-mas_nextprevwalk.patch
mm-add-vma_iter_nextprev_range-to-vma-iterator.patch
mm-avoid-rewalk-in-mmap_region.patch
