[TUHS] signals and blocked in I/O

Larry McVoy lm at mcvoy.com
Sat Dec 2 03:26:03 AEST 2017


On Fri, Dec 01, 2017 at 09:33:49AM -0700, Warner Losh wrote:
> > Or what you do is kill the process, tear down all of the pages except those
> > that are locked for I/O, leave those in the process and wait for the I/O to
> > get done.  That might be simpler.
> 
> Perhaps. Even that may have issues with cleanup because you may also need
> other pages to complete the I/O processing since I think that things like
> aio allocate a tiny bit of memory associated with the requesting process
> and need that memory to finish the I/O. It's certainly not a requirement
> that all I/O initiated by userland have no extra state stored in the
> process' address space associated with it. Since the unwinding happens at a
> layer higher than the disk driver, who knows what those guys do, eh?

Yeah, it's not an easy fix but the problem we are having right now is that
the system is thrashing.  Why the OOM code isn't fixing it I don't know.
It just feels busted.


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