DESCRIPTION¶
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 well.
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 the shutdown.
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.