Re: [patch 01/27] fs: cleanup files_lock

From: Eric W. Biederman
Date: Sat Apr 25 2009 - 01:35:33 EST


npiggin@xxxxxxx writes:

> Lock tty_files with tty_mutex, provide helpers to manipulate the per-sb
> files list, and unexport the files_lock spinlock.

This conflicts a bit with some of my ongoing work, which is generalizing
the file list to make it more useful and makes the tty case much less
of a special case.

Do you know if the performance improvement would be anywhere near as good if
file_list and file_list_lock becoming per inode?

Do you have any idea what the performance improvement with changing the file_list_lock
is?


> Index: linux-2.6/fs/open.c
> ===================================================================
> --- linux-2.6.orig/fs/open.c
> +++ linux-2.6/fs/open.c
> @@ -828,7 +828,7 @@ static struct file *__dentry_open(struct
> f->f_path.mnt = mnt;
> f->f_pos = 0;
> f->f_op = fops_get(inode->i_fop);
> - file_move(f, &inode->i_sb->s_files);
> + file_sb_list_add(f, inode->i_sb);

You can make this just:
if (!special_file(inode->i_mode))
file_add(f, &inode->i_files);

And save yourself a lot of complexity.

Eric
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