![dsl](/assets/img/avatar_default.png)
Due to a bug in mmap() the address space isn't counted against ulimit until the page is faulted in - so mmapping a large file suceeds, but cmp SIGSEGVs when it runs out of address space. Also I don't believe that the madvise( MAP_SEQUENTIAL) has the desired effect, and mmaping a large file is probably very bad for the UBC.