From 3d287de3b828226e5a450c7fd5bf4283792dc2b0 Mon Sep 17 00:00:00 2001 From: Dmitry Monakhov Date: Wed, 27 Oct 2010 22:08:46 -0400 Subject: [PATCH] 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 Signed-off-by: "Theodore Ts'o" --- fs/ext4/inode.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 9e60d0b8fa75..3ba237b0b2aa 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))