The patch titled
Subject: maple_tree: refine mas_preallocate() node calculations
has been added to the -mm mm-unstable branch. Its filename is
maple_tree-refine-mas_preallocate-node-calculations.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-refine-mas_preallocate-node-calculations.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: refine mas_preallocate() node calculations
Date: Wed, 31 May 2023 22:16:04 -0400
Calculate the number of nodes based on the pending write action instead of
assuming the worst case.
This addresses a performance regression introduced in platforms that have
longer allocation timing.
Link: https://lkml.kernel.org/r/20230601021605.2823123-14-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/maple_tree.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 43 insertions(+), 1 deletion(-)
--- a/lib/maple_tree.c~maple_tree-refine-mas_preallocate-node-calculations
+++ a/lib/maple_tree.c
@@ -5541,9 +5541,51 @@ EXPORT_SYMBOL_GPL(mas_store_prealloc);
*/
int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
{
+ MA_WR_STATE(wr_mas, mas, entry);
+ unsigned char node_size;
+ int request = 1;
int ret;
- mas_node_count_gfp(mas, 1 + mas_mt_height(mas) * 3, gfp);
+
+ if (unlikely(!mas->index && mas->last == ULONG_MAX))
+ goto ask_now;
+
+ mas_wr_store_setup(&wr_mas);
+ wr_mas.content = mas_start(mas);
+ /* Root expand */
+ if (unlikely(mas_is_none(mas) || mas_is_ptr(mas)))
+ goto ask_now;
+
+ if (unlikely(!mas_wr_walk(&wr_mas))) {
+ /* Spanning store, use worst case for now */
+ request = 1 + mas_mt_height(mas) * 3;
+ goto ask_now;
+ }
+
+ /* At this point, we are at the leaf node that needs to be altered. */
+ /* Exact fit, no nodes needed. */
+ if (wr_mas.r_min == mas->index && wr_mas.r_max == mas->last)
+ return 0;
+
+ mas_wr_end_piv(&wr_mas);
+ node_size = mas_wr_new_end(&wr_mas);
+ if (node_size >= mt_slots[wr_mas.type]) {
+ /* Split, worst case for now. */
+ request = 1 + mas_mt_height(mas) * 2;
+ goto ask_now;
+ }
+
+ /* New root needs a singe node */
+ if (unlikely(mte_is_root(mas->node)))
+ goto ask_now;
+
+ /* Potential spanning rebalance collapsing a node, use worst-case */
+ if (node_size - 1 <= mt_min_slots[wr_mas.type])
+ request = mas_mt_height(mas) * 2 - 1;
+
+ /* node store, slot store needs one node */
+ask_now:
+ mas_node_count_gfp(mas, request, gfp);
mas->mas_flags |= MA_STATE_PREALLOC;
if (likely(!mas_is_err(mas)))
return 0;
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
maple_tree-fix-static-analyser-cppcheck-issue.patch
maple_tree-avoid-unnecessary-ascending.patch
maple_tree-clean-up-mas_dfs_postorder.patch
maple_tree-add-debug-bug_on-and-warn_on-variants.patch
maple_tree-use-mas_bug_on-when-setting-a-leaf-node-as-a-parent.patch
maple_tree-use-mas_bug_on-in-mas_set_height.patch
maple_tree-use-mas_bug_on-from-mas_topiary_range.patch
maple_tree-use-mas_wr_bug_on-in-mas_store_prealloc.patch
maple_tree-use-mas_bug_on-prior-to-calling-mas_meta_gap.patch
maple_tree-return-error-on-mte_pivots-out-of-range.patch
maple_tree-make-test-code-work-without-debug-enabled.patch
mm-update-validate_mm-to-use-vma-iterator.patch
mm-update-vma_iter_store-to-use-mas_warn_on.patch
maple_tree-add-__init-and-__exit-to-test-module.patch
maple_tree-remove-unnecessary-check-from-mas_destroy.patch
maple_tree-mas_start-reset-depth-on-dead-node.patch
mm-mmap-change-do_vmi_align_munmap-for-maple-tree-iterator-changes.patch
maple_tree-try-harder-to-keep-active-node-after-mas_next.patch
maple_tree-try-harder-to-keep-active-node-with-mas_prev.patch
maple_tree-revise-limit-checks-in-mas_empty_area_rev.patch
maple_tree-fix-testing-mas_empty_area.patch
maple_tree-introduce-mas_next_slot-interface.patch
maple_tree-add-mas_next_range-and-mas_find_range-interfaces.patch
maple_tree-relocate-mas_rewalk-and-mas_rewalk_if_dead.patch
maple_tree-introduce-mas_prev_slot-interface.patch
maple_tree-add-mas_prev_range-and-mas_find_range_rev-interface.patch
maple_tree-clear-up-index-and-last-setting-in-single-entry-tree.patch
maple_tree-update-testing-code-for-mas_nextprevwalk.patch
mm-add-vma_iter_nextprev_range-to-vma-iterator.patch
mm-avoid-rewalk-in-mmap_region.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-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
mm-mmap-change-vma-iteration-order-in-do_vmi_align_munmap.patch
userfaultfd-fix-regression-in-userfaultfd_unmap_prep.patch
