Messages in this thread | | | Subject | Re: fanotify - overall design before I start sending patches | From | Peter Zijlstra <> | Date | Thu, 06 Aug 2009 12:29:08 +0200 |
| |
On Thu, 2009-08-06 at 11:20 +0100, Douglas Leeder wrote: > Pavel Machek wrote: > > On Wed 2009-08-05 17:46:16, Tvrtko Ursulin wrote: > >> On Wednesday 05 August 2009 03:05:34 Pavel Machek wrote: > > >> Just to make sure you haven't missed this - it is not that they have to > >> complete the whole operation before the timeout period (since you mention > >> realtime/mlock I suspect this is what you think?), but _during_ the operation > >> they have to show that they are active by sending something like keep alive > >> messages. > >> > >> Or you are worried about failing to meet even that on a loaded system? There > >> has to be something like this otherwise hung userspace client would kill the > >> whole system. > > > > Of course, I'm worried about failing to meet this on loaded > > system. And the fact that I _have_ to worry about that means that > > interface is ugly/broken. > > You mean that in 5 seconds, you won't have any point when you can tell > the kernel, "I'm still working"?
I have to agree with Pavel here, either you demand the monitor process is RT/mlock and can respond in time, in which case the interface doesn't need a 5 second timeout, or you cannot and you have a hole somewhere.
Now having the kernel depend on any user task to guarantee process is of course utterly insane too.
Sounds like a bad place to be, and I'd rather not have it.
If you really need the intermediate you might as well use a FUSE filesystem, but I suspect there's plenty of problems there as well.
It all reeks of ugly though..
/me craws back from whence he came.
| |