NALLOC
GEM_BUG_ON(atomic_read(&pt->used) > NALLOC * I915_PDES);
GEM_BUG_ON(atomic_read(px_used(pd)) > NALLOC * I915_PDES);
l = xreallocarray(NULL, NALLOC, sizeof(LINE));
for (i = 1; i < NALLOC; i++, l++)