Impact of having a large number of open file descriptors

[Kris Kennaway]

Robert Watson wrote:

> fsevents allows user processes to subscribe, effectively on a 
> per-filesystem basis, to namespace and file close operations.

...

> I think there's also considerable overlap with other kernel event 
> systems, such as audit, and we might benefit from thinking seriously 
> about enhancing those event systems rather than introducing a new one.  
> The design of fsevents is pretty much entirely dictated by the needs of 
> Spotlight and later Time Machine.  In particular, it's not clear to me 
> that the persistency requirements, which are a large part of the 
> fsevents design, are important to us... or are they?

Yes, I keep forgetting about audit for some reason :)  It might be that 
this is already good enough for my use case, although having to maintain 
a path -> inode mapping for millions of files will be potentially 
onerous (same for kevent anyway though).  Persistency across reboots for 
unread events would be nice but probably not essential (or worth the 
trouble).

Kris