From: Liam R. Howlett <Liam.Howlett@oracle.com>
Date: Thu, 17 Feb 2022 22:32:14 +0000 (-0500)
Subject: maple_tree: big node weight reduction
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=38d7f582872d8e13583bb2bf7f1215b253e9fc13;p=users%2Fjedix%2Flinux-maple.git

maple_tree: big node weight reduction

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index c8cf9490e940..9588c6d1d0c8 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -109,9 +109,14 @@ static const unsigned char mt_min_slots[] = {
 
 struct maple_big_node {
 	struct maple_pnode *parent;
-	struct maple_enode *slot[MAPLE_BIG_NODE_SLOTS];
 	unsigned long pivot[MAPLE_BIG_NODE_SLOTS - 1];
-	unsigned long gap[MAPLE_BIG_NODE_SLOTS];
+	union {
+		struct maple_enode *slot[MAPLE_BIG_NODE_SLOTS];
+		struct {
+			unsigned long padding[MAPLE_BIG_NODE_SLOTS/2 + 2];
+			unsigned long gap[MAPLE_BIG_NODE_SLOTS/2 + 2];
+		};
+	};
 	unsigned long min;
 	unsigned char b_end;
 	enum maple_type type;
@@ -1742,7 +1747,8 @@ static inline void mab_shift_right(struct maple_big_node *b_node,
 
 	memmove(b_node->pivot + shift, b_node->pivot, size);
 	memmove(b_node->slot + shift, b_node->slot, size);
-	memmove(b_node->gap + shift, b_node->gap, size);
+	if (b_node->type == maple_arange_64)
+		memmove(b_node->gap + shift, b_node->gap, size);
 }
 
 /*
@@ -2353,6 +2359,7 @@ bool mast_sibling_rebalance_right(struct maple_subtree_state *mast, bool free)
 
 	old_l = mast->orig_l->node;
 	if (mas_prev_sibling(mast->orig_l)) {
+		mast->bn->type = mte_node_type(mast->orig_l->node);
 		mast_rebalance_prev(mast, old_l);
 		return true;
 	}
@@ -3208,9 +3215,13 @@ static inline void mast_fill_bnode(struct maple_subtree_state *mast,
 {
 	bool cp = true;
 	struct maple_enode *old = mas->node;
-	unsigned char split, zero;
+	unsigned char split;
 
+	memset(mast->bn->gap, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->gap));
+	memset(mast->bn->slot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->slot));
+	memset(mast->bn->pivot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->pivot));
 	mast->bn->b_end = 0;
+
 	if (mte_is_root(mas->node)) {
 		cp = false;
 	} else {
@@ -3236,13 +3247,6 @@ static inline void mast_fill_bnode(struct maple_subtree_state *mast,
 
 	mast->bn->b_end--;
 	mast->bn->type = mte_node_type(mas->node);
-
-	zero = MAPLE_BIG_NODE_SLOTS - mast->bn->b_end - 2;
-	memset(mast->bn->gap + mast->bn->b_end + 1, 0,
-	       sizeof(unsigned long) * zero);
-	memset(mast->bn->slot + mast->bn->b_end + 1, 0, sizeof(void*) * zero--);
-	memset(mast->bn->pivot + mast->bn->b_end + 1, 0,
-	       sizeof(unsigned long) * zero);
 }
 
 /*