I like the idea, but I want to add another limit (pseudo code) : if(limit < 0) { error }.

```C
write_limit_high = global_option_get_long_in_range("WriteQueueLengthLimitHigh",0, 0, LONG_MAX);
write_limit_low = global_option_get_long_in_range("WriteQueueLengthLimitLow", (write_limit_high+1)/2, 0, write_limit_high-1 );
```