Re: [RFC,PATCH] dnotify: enhance or replace?

Rüdiger Klaehn
2004-03-24T16:52:18Z

John McCutchan wrote:

[snip]
> Maybe adding a rate limiter on these write events would be a better
> idea, live updates are usefull for the desktop. Also with a netlink
> socket I think the overhead of many events would drop siginificantly.
>
You could always merge read/write events if you get too many of them.
E.g. write [10,11] + write [11,12] => write [10,12]. But I never had
event buffer overflows with my tests. And a buffer of a few kbytes per
file system for fam won't be that bad, so I am not sure wether it is
nessecary to do something as complicated as rate limiting or merging.

> Also a couple other items I think need to be on the list of features,
>
> * Some way to not have an open file descriptor for each directory you
> are monitoring. This causes so many problems when unmounting, and this
> is really the most noticable problem for the user.
>
You can monitor a whole tree with a single file descriptor. But you need
at least one open fd per file system, so it would indeed be a problem
when unmounting.

> * Better event vocabulary, we should fire events for all VFS ops. I
> think right now it is limited to delete,create,written to. It would be
> good to tell the listener exactly what happened, moved,renamed, etc.
>
I had this for a short time, but I threw it away since I wanted to
concentrate on the event dispatch infrastructure first. It would not be
a big problem to add this again.