From: "Liam R. Howlett" <Liam.Howlett@oracle.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
maple-tree@lists.infradead.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Matthew Wilcox <willy@infradead.org>,
Suren Baghdasaryan <surenb@google.com>
Cc: "Liam R. Howlett" <Liam.Howlett@Oracle.com>,
stable@vger.kernel.org, Liam Howlett <Liam.Howlett@oracle.com>
Subject: [PATCH 4/8] maple_tree: remove extra smp_wmb() from mas_dead_leaves()
Date: Mon, 27 Mar 2023 14:55:28 -0400 [thread overview]
Message-ID: <20230327185532.2354250-5-Liam.Howlett@oracle.com> (raw)
In-Reply-To: <20230327185532.2354250-1-Liam.Howlett@oracle.com>
From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>
The call to mte_set_dead_node() before the smp_wmb() already calls
smp_wmb() so this is not needed. This is an optimization for the RCU mode
of the maple tree.
Link: https://lkml.kernel.org/r/20230227173632.3292573-5-surenb@google.com
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Cc: stable@vger.kernel.org
Signed-off-by: Liam Howlett <Liam.Howlett@oracle.com>
---
lib/maple_tree.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 44d6ce30b28e..3d5ab02f981a 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5517,7 +5517,6 @@ unsigned char mas_dead_leaves(struct ma_state *mas, void __rcu **slots,
break;
mte_set_node_dead(entry);
- smp_wmb(); /* Needed for RCU */
node->type = type;
rcu_assign_pointer(slots[offset], node);
}
--
2.39.2
next prev parent reply other threads:[~2023-03-27 19:02 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-27 18:55 [PATCH 0/8] Fix VMA tree modification under mmap read lock Liam R. Howlett
2023-03-27 18:55 ` [PATCH 1/8] maple_tree: be more cautious about dead nodes Liam R. Howlett
2023-03-27 18:55 ` [PATCH 2/8] maple_tree: detect dead nodes in mas_start() Liam R. Howlett
2023-03-27 18:55 ` [PATCH 3/8] maple_tree: fix freeing of nodes in rcu mode Liam R. Howlett
2023-03-27 18:55 ` Liam R. Howlett [this message]
2023-03-27 18:55 ` [PATCH 5/8] maple_tree: fix write memory barrier of nodes once dead for RCU mode Liam R. Howlett
2023-03-27 19:05 ` Liam R. Howlett
2023-03-27 19:45 ` Andrew Morton
2023-03-27 18:55 ` [PATCH 6/8] maple_tree: add smp_rmb() to dead node detection Liam R. Howlett
2023-03-27 18:55 ` [PATCH 7/8] maple_tree: add RCU lock checking to rcu callback functions Liam R. Howlett
2023-03-27 18:55 ` [PATCH 8/8] mm: enable maple tree RCU mode by default Liam R. Howlett
2023-03-27 19:38 ` Andrew Morton
2023-03-27 19:43 ` Liam R. Howlett
2023-04-11 1:25 ` kernel test robot
2023-04-11 2:25 ` Matthew Wilcox
2023-03-27 19:35 ` [PATCH 0/8] Fix VMA tree modification under mmap read lock Andrew Morton
2023-03-27 19:48 ` Liam R. Howlett
2023-03-28 9:10 ` Vlastimil Babka
2023-03-28 13:02 ` Liam R. Howlett
2023-04-03 19:44 ` Liam R. Howlett
2023-04-03 20:19 ` Andrew Morton
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