Re: [patch] epoll use a single inode ...

From: Linus Torvalds
Date: Tue Mar 06 2007 - 20:27:37 EST




On Tue, 6 Mar 2007, Davide Libenzi wrote:
>
> I'm OK with everything that avoid code duplication due to those fake
> inodes. The change can be localized inside the existing API, so it doesn't
> really affect me externally.

Can you try with the first patch version that doesn't do anything special
at all, and just uses a single dentry.

Yeah, the dentry name will be identical, and so you would see something
like "7 -> signalfd:signalfd" when you do "ls -l /proc/<pid>/fd/" on a
task that has such a special file descriptor (with no way to tell
different timerfd's and signalfd's apart), but I think it's better to
start off simple than to overdesign things.

And trying to tell them apart sounds a bit like overdesign, if only
because I really don't see why anybody would really *care*. So it's a
timer for poll/select/epoll - why care about anything else?

If it really really turns out that people care, we know how we can do it.
We'd hook into "proc_fd_link()" and we'd allow a per-file mntget/dget that
we could use to let special filesystems create fake entries on demand. So
it's not impossible, it's just likely simply not needed.

Linus
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