The patch titled
Subject: maple_tree: add benchmarking for mas_for_each
has been added to the -mm mm-unstable branch. Its filename is
maple_tree-add-benchmarking-for-mas_for_each.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-add-benchmarking-for-mas_for_each.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: maple_tree: add benchmarking for mas_for_each
Date: Mon, 12 Jun 2023 16:39:38 -0400
Patch series "Reduce preallocations for maple tree", v2.
Initial work on preallocations showed no regression in performance during
testing, but recently some users (both on [1] and off [android] list) have
reported that preallocating the worst-case number of nodes has caused some
slow down. This patch set addresses the number of allocations in a few
ways.
During munmap() most munmap() operations will remove a single VMA, so
leverage the fact that the maple tree can place a single pointer at range
0 - 0 without allocating. This is done by changing the index in the
'sidetree'.
Re-introduce the entry argument to mas_preallocate() so that a more
intelligent guess of the node count can be made.
During development of v2 of this patch set, I also noticed that the number
of nodes being allocated for a rebalance was beyond what could possibly be
needed. This is addressed in patch 0008.
Patches are in the following order:
0001-0002: Testing framework for benchmarking some operations
0003-0004: Reduction of maple node allocation in sidetree
0005: Small cleanup of do_vmi_align_munmap()
0006-0015: mas_preallocate() calculation change
0016: Change the vma iterator order
This patch (of 16):
Add a way to test the speed of mas_for_each() to the testing code.
Link: https://lkml.kernel.org/r/20230612203953.2093911-1-Liam.Howlett@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20230612203953.2093911-2-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/test_maple_tree.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
--- a/lib/test_maple_tree.c~maple_tree-add-benchmarking-for-mas_for_each
+++ a/lib/test_maple_tree.c
@@ -44,6 +44,7 @@ atomic_t maple_tree_tests_passed;
/* #define BENCH_WALK */
/* #define BENCH_MT_FOR_EACH */
/* #define BENCH_FORK */
+/* #define BENCH_MAS_FOR_EACH */
#ifdef __KERNEL__
#define mt_set_non_kernel(x) do {} while (0)
@@ -1705,6 +1706,36 @@ static noinline void __init bench_mt_for
}
#endif
+#if defined(BENCH_MAS_FOR_EACH)
+static noinline void __init bench_mas_for_each(struct maple_tree *mt)
+{
+ int i, count = 1000000;
+ unsigned long max = 2500;
+ void *entry;
+ MA_STATE(mas, mt, 0, 0);
+
+ for (i = 0; i < max; i += 5) {
+ int gap = 4;
+ if (i % 30 == 0)
+ gap = 3;
+ mtree_store_range(mt, i, i + gap, xa_mk_value(i), GFP_KERNEL);
+ }
+
+ rcu_read_lock();
+ for (i = 0; i < count; i++) {
+ unsigned long j = 0;
+
+ mas_for_each(&mas, entry, max) {
+ MT_BUG_ON(mt, entry != xa_mk_value(j));
+ j += 5;
+ }
+ mas_set(&mas, 0);
+ }
+ rcu_read_unlock();
+
+}
+#endif
+
/* check_forking - simulate the kernel forking sequence with the tree. */
static noinline void __init check_forking(struct maple_tree *mt)
{
@@ -3430,6 +3461,13 @@ static int __init maple_tree_seed(void)
mtree_destroy(&tree);
goto skip;
#endif
+#if defined(BENCH_MAS_FOR_EACH)
+#define BENCH
+ mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE);
+ bench_mas_for_each(&tree);
+ mtree_destroy(&tree);
+ goto skip;
+#endif
mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE);
check_iteration(&tree);
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
mm-mprotect-fix-do_mprotect_pkey-limit-check.patch
maple_tree-add-benchmarking-for-mas_for_each.patch
maple_tree-add-benchmarking-for-mas_prev.patch
mm-move-unmap_vmas-declaration-to-internal-header.patch
mm-change-do_vmi_align_munmap-side-tree-index.patch
mm-remove-prev-check-from-do_vmi_align_munmap.patch
maple_tree-introduce-__mas_set_range.patch
mm-remove-re-walk-from-mmap_region.patch
maple_tree-adjust-node-allocation-on-mas_rebalance.patch
maple_tree-re-introduce-entry-to-mas_preallocate-arguments.patch
mm-use-vma_iter_clear_gfp-in-nommu.patch
mm-set-up-vma-iterator-for-vma_iter_prealloc-calls.patch
maple_tree-move-mas_wr_end_piv-below-mas_wr_extend_null.patch
maple_tree-update-mas_preallocate-testing.patch
maple_tree-refine-mas_preallocate-node-calculations.patch
maple_tree-reduce-resets-during-store-setup.patch
mm-mmap-change-vma-iteration-order-in-do_vmi_align_munmap.patch
userfaultfd-fix-regression-in-userfaultfd_unmap_prep.patch
