The two cases are:
/sys/src/9/pc/mmu.c:510,513
if(didmmuinit)
map = xspanalloc(BY2PG, BY2PG, 0);
else
map = rampage();
xspanalloc returns zeroed memory. rampage is only called early
in startup, and returns virgin memory which in the olden days
would have been zeroed at boot time. But nowadays:
/sys/src/9/pc/memory.c:443
/* memset(va, 0, MB); so damn slow to memset all of
memory */
So I think you want to clear the page only for the rampage case.
