Subject: Re: imon in NetBSD?
To: David Young <>
From: Pavel Cahyna <>
List: tech-kern
Date: 01/09/2005 16:01:44
On Sat, 08 Jan 2005 18:52:40 -0600, David Young wrote:

> Something I did not understand is why the VFS layer does not already
> issue the kevent notifications.

There is a reason which has something to do with the vnode locking
protocol and Jaromir Dolecek once told it to me, but I forgot it. Jaromir?

>> Also there is one other serious issue.  kqueue works by monitoring open
>> file descriptors, while imon works with path names.  So imon can easily
>> monitor a big amount of files, but doing the same thing with kqueue can
>> be problematic (you need to increase kern.maxfiles).  Just consider
> I have always thought that the way to solve this is to extend the vnode
> kevents to make them optionally "heritable" by the vnodes in the
> subtree, and then extend the "kdata" to tell me the affected path in the
> subtree. Now I can listen on one kevent descriptor for events on the
> whole subtree. I don't claim to know whether/how that heritability will
> work.

Couldn't kqueue continue to monitor files that you have closed? In a
similar way that mmaped files don't get unmapped if you close the file

Bye	Pavel