Commit f0b3d94c authored by Liam R. Howlett's avatar Liam R. Howlett Committed by Peng Zhang
Browse files

maple_tree: don't find node end in mtree_lookup_walk() 

mainline inclusion
from mainline-v6.8-rc1
commit 24662decdd44645e8f027d7912be962dd461d1aa
category: performance
bugzilla: https://gitee.com/openeuler/kernel/issues/I9EHBO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=24662decdd44645e8f027d7912be962dd461d1aa

--------------------------------

Since the pivot being set is now reliable, the optimized loop no longer
needs to find the node end.  The redundant check for a dead node can also
be avoided as there is no danger of using the wrong pivot since the
results will be thrown out in the case of a dead node by the later check.

This patch also adds a benchmark test for the function to the maple tree
test framework.  The benchmark shows an average increase performance of
5.98% over 3 runs with this commit.

Link: https://lkml.kernel.org/r/20231101171629.3612299-12-Liam.Howlett@oracle.com


Signed-off-by: default avatarLiam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarZhangPeng <zhangpeng362@huawei.com>
parent f690eac7

lib/maple_tree.c

+3 −9
Original line number Diff line number Diff line
@@ -3742,23 +3742,17 @@ static inline void *mtree_lookup_walk(struct ma_state *mas) 
	enum maple_type type;

	void __rcu **slots;

	unsigned char end;

	unsigned long max;



	next = mas->node;

	max = ULONG_MAX;

	do {

		offset = 0;

		node = mte_to_node(next);

		type = mte_node_type(next);

		pivots = ma_pivots(node, type);

		end = ma_data_end(node, type, pivots, max);

		if (unlikely(ma_dead_node(node)))

			goto dead_node;

		end = mt_pivots[type];

		offset = 0;

		do {

			if (pivots[offset] >= mas->index) {

				max = pivots[offset];

			if (pivots[offset] >= mas->index)

				break;

			}

		} while (++offset < end);



		slots = ma_slots(node, type);

lib/test_maple_tree.c

+21 −0
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ atomic_t maple_tree_tests_passed; 
/* #define BENCH_NODE_STORE */

/* #define BENCH_AWALK */

/* #define BENCH_WALK */

/* #define BENCH_LOAD */

/* #define BENCH_MT_FOR_EACH */

/* #define BENCH_FORK */

/* #define BENCH_MAS_FOR_EACH */
@@ -1754,6 +1755,19 @@ static noinline void __init bench_walk(struct maple_tree *mt) 
}

#endif



#if defined(BENCH_LOAD)

static noinline void __init bench_load(struct maple_tree *mt)

{

	int i, max = 2500, count = 550000000;



	for (i = 0; i < max; i += 10)

		mtree_store_range(mt, i, i + 5, xa_mk_value(i), GFP_KERNEL);



	for (i = 0; i < count; i++)

		mtree_load(mt, 1470);

}

#endif



#if defined(BENCH_MT_FOR_EACH)

static noinline void __init bench_mt_for_each(struct maple_tree *mt)

{
@@ -3623,6 +3637,13 @@ static int __init maple_tree_seed(void) 
	mtree_destroy(&tree);

	goto skip;

#endif

#if defined(BENCH_LOAD)

#define BENCH

	mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE);

	bench_load(&tree);

	mtree_destroy(&tree);

	goto skip;

#endif

#if defined(BENCH_FORK)

#define BENCH

	bench_forking();