[merged mm-stable] maple_tree-refine-mas_preallocate-node-calculations.patch removed from -mm tree

[merged mm-stable] maple_tree-refine-mas_preallocate-node-calculations.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: maple_tree: refine mas_preallocate() node calculations
has been removed from the -mm tree.  Its filename was
     maple_tree-refine-mas_preallocate-node-calculations.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Subject: maple_tree: refine mas_preallocate() node calculations
Date: Mon, 24 Jul 2023 14:31:55 -0400

Calculate the number of nodes based on the pending write action instead
of assuming the worst case.

This addresses a performance regression introduced in platforms that
have longer allocation timing.

Link: https://lkml.kernel.org/r/20230724183157.3939892-14-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/maple_tree.c |   44 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

--- a/lib/maple_tree.c~maple_tree-refine-mas_preallocate-node-calculations
+++ a/lib/maple_tree.c
@@ -5535,9 +5535,51 @@ EXPORT_SYMBOL_GPL(mas_store_prealloc);
  */
 int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
 {
+	MA_WR_STATE(wr_mas, mas, entry);
+	unsigned char node_size;
+	int request = 1;
 	int ret;
 
-	mas_node_count_gfp(mas, 1 + mas_mt_height(mas) * 3, gfp);
+
+	if (unlikely(!mas->index && mas->last == ULONG_MAX))
+		goto ask_now;
+
+	mas_wr_store_setup(&wr_mas);
+	wr_mas.content = mas_start(mas);
+	/* Root expand */
+	if (unlikely(mas_is_none(mas) || mas_is_ptr(mas)))
+		goto ask_now;
+
+	if (unlikely(!mas_wr_walk(&wr_mas))) {
+		/* Spanning store, use worst case for now */
+		request = 1 + mas_mt_height(mas) * 3;
+		goto ask_now;
+	}
+
+	/* At this point, we are at the leaf node that needs to be altered. */
+	/* Exact fit, no nodes needed. */
+	if (wr_mas.r_min == mas->index && wr_mas.r_max == mas->last)
+		return 0;
+
+	mas_wr_end_piv(&wr_mas);
+	node_size = mas_wr_new_end(&wr_mas);
+	if (node_size >= mt_slots[wr_mas.type]) {
+		/* Split, worst case for now. */
+		request = 1 + mas_mt_height(mas) * 2;
+		goto ask_now;
+	}
+
+	/* New root needs a singe node */
+	if (unlikely(mte_is_root(mas->node)))
+		goto ask_now;
+
+	/* Potential spanning rebalance collapsing a node, use worst-case */
+	if (node_size  - 1 <= mt_min_slots[wr_mas.type])
+		request = mas_mt_height(mas) * 2 - 1;
+
+	/* node store, slot store needs one node */
+ask_now:
+	mas_node_count_gfp(mas, request, gfp);
 	mas->mas_flags |= MA_STATE_PREALLOC;
 	if (likely(!mas_is_err(mas)))
 		return 0;
_

Patches currently in -mm which might be from Liam.Howlett@oracle.com are

maple_tree-add-hex-output-to-maple_arange64-dump.patch
maple_tree-reorder-replacement-of-nodes-to-avoid-live-lock.patch
maple_tree-introduce-mas_put_in_tree.patch
maple_tree-introduce-mas_tree_parent-definition.patch
maple_tree-change-mas_adopt_children-parent-usage.patch
maple_tree-replace-data-before-marking-dead-in-split-and-spanning-store.patch