void slow_shut_down(int minutes)
Schedule a shutdown for the near future. minutes is the
desired time in minutes till the shutdown:
six, if just the user reserve has been put into use.
one, if the (smaller) master reserve has been put into use as
The interpreter calls this function when it runs low on
memory. At this time, it has freed its reserve, but since it
won't last long, the interpreter needs to be shut down. The
delay is to give the users the opportunity to finish their
current tasks, but don't take the 'minutes' for granted, just
deduce the urgency from it.
It is possible that the driver may reallocate some memory
after the function has been called, and then run again into a
low memory situation, calling this function again.
This function might load an 'Armageddon' object and tell it
what to do. It is the Armageddon object then which performs
Technical: The memory handling of the interpreter includes
three reserved areas: user, system and master. All three are
there to insure that the system shuts down gracefully when the
memory runs out: the user area to give the users time to
quit normally, the others to enable emergency-logouts when the
user reserve is used up as well.
The areas are allocated at start of the interpreter, and
released when no more memory could be obtained from the host.
In such a case, one of the remaining areas is freed (so the
operation can continue a short while) and a garbage collection
is initiated. If the garbage collection recycles enough memory
(either true garbage or by the aid of the quota_demon) to
reallocate the areas, all is fine, else the system shut down
is invoked by a call to this function.
quota_demon(M), notify_shutdown(M), shutdown(E), malloc(D), memory(C)