From 8c0a85377048b64c880e76ec7368904fe46d0b94 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Wed, 26 Sep 2012 11:33:07 +1000
Subject: fs: push rcu_barrier() from deactivate_locked_super() to filesystems
There's no reason to call rcu_barrier() on every
deactivate_locked_super(). We only need to make sure that all delayed rcu
free inodes are flushed before we destroy related cache.
Removing rcu_barrier() from deactivate_locked_super() affects some fast
paths. E.g. on my machine exit_group() of a last process in IPC
namespace takes 0.07538s. rcu_barrier() takes 0.05188s of that time.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/btrfs/inode.c | 5 +++++
1 file changed, 5 insertions(+)
(limited to 'fs/btrfs/inode.c')
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ec154f95464..cf03a91d806 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7076,6 +7076,11 @@ static void init_once(void *foo)
void btrfs_destroy_cachep(void)
{
+ /*
+ * Make sure all delayed rcu free inodes are flushed before we
+ * destroy cache.
+ */
+ rcu_barrier();
if (btrfs_inode_cachep)
kmem_cache_destroy(btrfs_inode_cachep);
if (btrfs_trans_handle_cachep)
--
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