* Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> [231215 02:46]:
> The last range stored in maple tree is typically quite large. By
> checking if it exceeds the sum of the remaining ranges in that node, it
> is possible to avoid checking all other gaps.
>
> Running the maple tree test suite in user mode almost always results in
> a near 100% hit rate for this optimization.
This should only be triggered for right-most nodes and root though,
correct (mas->max == ULONG_MAX from just before this)?
I wonder if it's worth special case checking the first gap if the node
min is 0 as well. Might be worth looking at, but this patch is
certainly worth doing.
>
> Signed-off-by: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx>
Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> ---
> lib/maple_tree.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index c9a970ea20dd..6f241bb38799 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -1518,6 +1518,9 @@ static unsigned long mas_leaf_max_gap(struct ma_state *mas)
> gap = ULONG_MAX - pivots[max_piv];
> if (gap > max_gap)
> max_gap = gap;
> +
> + if (max_gap > pivots[max_piv] - mas->min)
> + return max_gap;
> }
>
> for (; i <= max_piv; i++) {
> --
> 2.20.1
>
