Re: What to expect with the 2.6 VM

Jamie Lokier
2003-07-04T01:20:05Z

Andrea Arcangeli wrote:
> so you agree it'd better be a separate syscall

Per-page protections might be workable just through mremap(). As you
say, it's just a matter of appropriate bits in the swap entry. To
userspace it is a transparent performance improvement.

Unfortunately without an appropriate bit in the pte too, that
restricts per-page protections to work only with shared mappings, or
anon mappings which have not been forked, due to the lack of COW. It
would still be a good optimisation, although it would be a shame if,
say, a GC implementation of malloc et al. (eg. Boehm's allocator)
would not be transparent over fork().

-- Jamie