swp_pager_meta_build DoS printf

[Bjoern A. Zeeb]

Hey,

hitting this printf in swp_pager_meta_build()

                        if (uma_zone_exhausted(swap_zone)) {
                                printf("swap zone exhausted, increase kern.maxswzone\n");
                                vm_pageout_oom(VM_OOM_SWAPZ);
                                pause("swzonex", 10);
                        } else

seems to be an effective way to put the machine into a state of no recovery
unless the memory situation would be able to clear itself.  Not that it wouldn't
otherwise be any better but in addition having a couple of tenthousands of these
going to console as well is really not helpful to try to do anything either.  Can
we make it a log() call or something?

/bz

PS: I am not sure as I have seen it on someone else's machines and it's
probably been ZFS that caused it.  I unfortunately neither had a way to
get back in or break to a kernel debugger, so information is sparse.

-- 
Bjoern A. Zeeb                                 You have to have visions!
   It does not matter how good you are. It matters what good you do!