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authorLiam R. Howlett <Liam.Howlett@oracle.com>2023-07-24 14:31:55 -0400
committerAndrew Morton <akpm@linux-foundation.org>2023-08-18 10:12:50 -0700
commit17983dc617837a588a52848ab4034d8efa6c1fa6 (patch)
tree889f63c90352aa40c8360f78fe115cab5305e28b /lib
parent0b8bb544b1a7051c9072c26ca03a7840fb9573ad (diff)
maple_tree: refine mas_preallocate() node calculations
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/20230724183157.3939892-14-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/maple_tree.c44
1 files changed, 43 insertions, 1 deletions
diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index db61cdd8a649..4a111785360f 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5535,9 +5535,51 @@ 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;