On 2015-11-12 01:42, Theo de Raadt wrote:
On 2015-11-12 01:30, Theo de Raadt wrote:
>> I find this conversation puzzling, since even back in BSD 4.3, read()
>> was
>> actually implemented by memory mapping the underlying file.
>
> That is an wildly incorrect description of the 4.3 BSD buffer cache,
> furthermore 4.3 lacked a working mmap() to hit the coherency issue.
Wait, so if you make a read-only mmap(), will the buffer in OpenBSD be
"unified" in the sense that fwrite():s always will be immediately
visible in the memory mapped version?
My reply is specifically about what Howard said.
(This is what I understood that Howard suggested would apply from BSD
4.3 and on and Theo now said not was correct, so, my question is if
that
behavior was introduced later in OpenBSD.)
I made none of the claims you are composing.
Aha noted, so unifying the buffer cache then is still altogether in the
future. Thanks for clarifyign.
