Sandro/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-09-18 23:09:29 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

maple_tree: optimise mas_wr_node_store() when not in rcu mode

Browse Source 
Clearing the entire node on the stack is unnecessary since most of the
node will be overwritten anyways.  Just clear what isn't used after the
data is in place.

Benchmarking shows a speedup of 0.67% on a height 4 tree with 2048
entries.

Link: https://lore.kernel.org/20260821192627.4085470-10-liam@infradead.org
Signed-off-by: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Chris Mason <clm@meta.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joe Perches <joe@perches.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liam R. Howlett (Oracle)
2026-08-24 18:43:30 -07:00
committed by Andrew Morton
parent 4bd59d5bc2
commit 88f87f8812
1 changed files with 17 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/maple_tree.c
+17 -3
View File
@@ -3187,7 +3187,7 @@ static void mas_wr_spanning_store(struct ma_wr_state *wr_mas)
static inline void mas_wr_node_store(struct ma_wr_state *wr_mas)
{
unsigned char dst_offset, offset_end;
unsigned char copy_size, node_pivots;
unsigned char copy_size, node_pivots, node_slots;
struct maple_node reuse, *newnode;
unsigned long *dst_pivots;
void __rcu **dst_slots;
@@ -3200,6 +3200,7 @@ static inline void mas_wr_node_store(struct ma_wr_state *wr_mas)
in_rcu = mt_in_rcu(mas->tree);
offset_end = wr_mas->offset_end;
node_pivots = mt_pivots[wr_mas->type];
node_slots = mt_slots[wr_mas->type];
/* Assume last adds an entry */
new_end = mas->end + 1 - offset_end + mas->offset;
if (mas->last == wr_mas->end_piv) {
@@ -3211,7 +3212,6 @@ static inline void mas_wr_node_store(struct ma_wr_state *wr_mas)
if (in_rcu) {
newnode = mas_pop_node(mas);
} else {
memset(&reuse, 0, sizeof(struct maple_node));
newnode = &reuse;
}
@@ -3255,7 +3255,21 @@ static inline void mas_wr_node_store(struct ma_wr_state *wr_mas)
dst_pivots[new_end] = mas->max;
done:
mas_leaf_set_meta(newnode, maple_leaf_64, new_end);
if (!in_rcu && new_end + 2 < node_slots) {
unsigned char clear_from = new_end + 1;
/*
* Note that the last slot is never cleared, since the metadata
* will be stored there or it has a value.
*/
memset(dst_slots + clear_from, 0,
sizeof(void __rcu *) * (node_slots - clear_from));
if (clear_from < node_pivots)
memset(dst_pivots + clear_from, 0,
sizeof(unsigned long) * (node_pivots - clear_from));
}
mas_leaf_set_meta(newnode, wr_mas->type, new_end);
if (in_rcu) {
struct maple_enode *old_enode = mas->node;