From: Sidhartha Kumar Date: Thu, 27 Feb 2025 20:48:21 +0000 (+0000) Subject: maple_tree: break on convergence in mas_spanning_rebalance() X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0bd7eff46a19403e13cd6aeca39f58947a18b18d;p=users%2Fjedix%2Flinux-maple.git maple_tree: break on convergence in mas_spanning_rebalance() This allows support for using the vacant height to calculate the worst case number of nodes needed for wr_rebalance operation. mas_spanning_rebalance() was seen to perform unnecessary node allocations. We can reduce allocations by breaking early during the rebalancing loop once we realize that we have ascended to a common ancestor. Link: https://lkml.kernel.org/r/20250227204823.758784-5-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Suggested-by: Liam Howlett Reviewed-by: Wei Yang Reviewed-by: Liam R. Howlett Signed-off-by: Andrew Morton --- diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 6a59f2d15769..8cea953a0cb5 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -2895,11 +2895,24 @@ static void mas_spanning_rebalance(struct ma_state *mas, mast_combine_cp_right(mast); mast->orig_l->last = mast->orig_l->max; - if (mast_sufficient(mast)) - continue; + if (mast_sufficient(mast)) { + if (mast_overflow(mast)) + continue; + + if (mast->orig_l->node == mast->orig_r->node) { + /* + * The data in b_node should be stored in one + * node and in the tree + */ + slot = mast->l->offset; + /* May be a new root stored in mast->bn */ + if (mas_is_root_limits(mast->orig_l)) + new_height++; + break; + } - if (mast_overflow(mast)) continue; + } /* May be a new root stored in mast->bn */ if (mas_is_root_limits(mast->orig_l)) {