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authorDmitry Monakhov <dmonakhov@openvz.org>2010-10-27 22:08:46 -0400
committerTheodore Ts'o <tytso@mit.edu>2010-10-27 22:08:46 -0400
commit3d287de3b828226e5a450c7fd5bf4283792dc2b0 (patch)
tree4adcc534e2042aed924750df3ef2433bd2f14fd8
parentbeed5ecbaa377fa8bb6a54a6608e8725a21efdbc (diff)
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ext4: optimize orphan_list handling for ext4_setattr
Surprisingly chown() on ext4 is not SMP scalable operation. Due to unconditional orphan_del(NULL, inode) in ext4_setattr() result in significant performance overhead because of global orphan mutex, especially in no-journal mode (where orphan_add() is noop). It is possible to skip explicit orphan_del if possible. Results of fchown() micro-benchmark in no-journal mode while (1) { iteration++; fchown(fd, uid, gid); fchown(fd, uid + 1, gid + 1) } measured: iterations per millisecond | nr_tasks | w/o patch | with patch | | 1 | 142 | 185 | | 4 | 109 | 642 | Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
-rw-r--r--fs/ext4/inode.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9e60d0b..3ba237b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5281,6 +5281,7 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = dentry->d_inode;
int error, rc = 0;
+ int orphan = 0;
const unsigned int ia_valid = attr->ia_valid;
error = inode_change_ok(inode, attr);
@@ -5336,8 +5337,10 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
error = PTR_ERR(handle);
goto err_out;
}
-
- error = ext4_orphan_add(handle, inode);
+ if (ext4_handle_valid(handle)) {
+ error = ext4_orphan_add(handle, inode);
+ orphan = 1;
+ }
EXT4_I(inode)->i_disksize = attr->ia_size;
rc = ext4_mark_inode_dirty(handle, inode);
if (!error)
@@ -5355,6 +5358,7 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
goto err_out;
}
ext4_orphan_del(handle, inode);
+ orphan = 0;
ext4_journal_stop(handle);
goto err_out;
}
@@ -5377,7 +5381,7 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
* If the call to ext4_truncate failed to get a transaction handle at
* all, we need to clean up the in-core orphan list manually.
*/
- if (inode->i_nlink)
+ if (orphan && inode->i_nlink)
ext4_orphan_del(NULL, inode);
if (!rc && (ia_valid & ATTR_MODE))