Commit 7e552dcd authored by Peng Zhang's avatar Peng Zhang Committed by Andrew Morton
Browse files

maple_tree: avoid checking other gaps after getting the largest gap 

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.

Link: https://lkml.kernel.org/r/20231215074632.82045-1-zhangpeng.00@bytedance.com


Signed-off-by: default avatarPeng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: default avatarLiam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent f7ef5fe7

lib/maple_tree.c

+3 −0
Original line number Diff line number Diff line
@@ -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++) {