linux-kernel - [PATCH RFC 3/6] maple_tree: use percpu sheaves for maple_node

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20241112-slub-percpu-caches-v1-3-ddc0bdc27e05@suse.cz>
Date: Tue, 12 Nov 2024 17:38:47 +0100
From: Vlastimil Babka <vbabka@...e.cz>
To: Suren Baghdasaryan <surenb@...gle.com>, 
 "Liam R. Howlett" <Liam.Howlett@...cle.com>, 
 Christoph Lameter <cl@...ux.com>, David Rientjes <rientjes@...gle.com>, 
 Pekka Enberg <penberg@...nel.org>, Joonsoo Kim <iamjoonsoo.kim@....com>
Cc: Roman Gushchin <roman.gushchin@...ux.dev>, 
 Hyeonggon Yoo <42.hyeyoo@...il.com>, 
 "Paul E. McKenney" <paulmck@...nel.org>, 
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, 
 Matthew Wilcox <willy@...radead.org>, Boqun Feng <boqun.feng@...il.com>, 
 Uladzislau Rezki <urezki@...il.com>, linux-mm@...ck.org, 
 linux-kernel@...r.kernel.org, rcu@...r.kernel.org, 
 maple-tree@...ts.infradead.org, Vlastimil Babka <vbabka@...e.cz>
Subject: [PATCH RFC 3/6] maple_tree: use percpu sheaves for
 maple_node_cache

Setup the maple_node_cache with percpu sheaves of size 32 to hopefully
improve its performance. Change the single node rcu freeing in
ma_free_rcu() to use kfree_rcu() instead of the custom callback, which
allows the rcu_free sheaf batching to be used. Note there are other
users of mt_free_rcu() where larger parts of maple tree are submitted to
call_rcu() as a whole, and that cannot use the rcu_free sheaf, but it's
still possible for maple nodes freed this way to be reused via the barn,
even if only some cpus are allowed to process rcu callbacks.

Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
---
 lib/maple_tree.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 3619301dda2ebeaaba8a73837389b6ee3c7e1a3f..c69365e17fcbfe963dcedd0de07335fc6bbdfb27 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -194,7 +194,7 @@ static void mt_free_rcu(struct rcu_head *head)
 static void ma_free_rcu(struct maple_node *node)
 {
 	WARN_ON(node->parent != ma_parent_ptr(node));
-	call_rcu(&node->rcu, mt_free_rcu);
+	kfree_rcu(node, rcu);
 }

 static void mas_set_height(struct ma_state *mas)
@@ -6299,9 +6299,14 @@ bool mas_nomem(struct ma_state *mas, gfp_t gfp)

 void __init maple_tree_init(void)
 {
+	struct kmem_cache_args args = {
+		.align  = sizeof(struct maple_node),
+		.sheaf_capacity = 32,
+	};
+
 	maple_node_cache = kmem_cache_create("maple_node",
-			sizeof(struct maple_node), sizeof(struct maple_node),
-			SLAB_PANIC, NULL);
+			sizeof(struct maple_node), &args,
+			SLAB_PANIC);
 }

 /**

-- 
2.47.0