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Subject: Re: [RFC][PATCH] inotify 0.10.0
From: Ray Lee <ray-lk@madrabbit.org>
To: John McCutchan <ttb@tentacle.dhs.org>
Cc: Andrew Morton <akpm@osdl.org>, rml@novell.com,
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Date: Tue, 28 Sep 2004 14:32:12 -0700
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On Tue, 2004-09-28 at 16:40 -0400, John McCutchan wrote:
> On Tue, 2004-09-28 at 15:08, Andrew Morton wrote:
> > Ray Lee <ray-lk@madrabbit.org> wrote:
> > >
> > > The current way pads out the structure unnecessarily, and still doesn't
> > > handle the really long filenames, by your admission. It incurs extra
> > > syscalls, as few filenames are really 256 characters in length. 
> > 
> > Why don't you pass a file descriptor into the syscall instead of a pathname?
> > You can then take a ref on the inode and userspace can close the file.
> > That gets you permission checking for free.
> > 
> 
> I don't think moving inotify to a syscall based interface is worth it.
> 
> First off, on startup, this would require about 2k open() calls,
> followed by 2k syscalls to inotify.

And then 2k close() calls.

> Not as nice as just 2k ioctl() calls.

<shrug> Syscalls aren't free, but they aren't the end of the world.

> The character device interface right now suits it perfectly. If we used
> syscalls we would need to provide a syscall that gives user space a FD
> that it can read events on,

Again, apologies, I should know better than to write email on short
sleep. All I was suggesting was that we pass in an fd that comes from
open(), and that we should look at replacing the ioctl with write(). I
like it as a character device, honest.

Ray

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