Re: [PATCH] limited support for non-root mlock()

[Justus Winter]

Hi :)

Quoting Samuel Thibault (2015-07-08 15:55:33)
> I have implemented a start of support for calling mlock() in a non-root
> process, which I have attached.

Sweet.  You talked about that in your FOSDEM talk, right?  Ever since
I thought that managing this in userspace is the better solution, then
again, the implementation is simple enough.

> I had to introduce a newer RPC since the existing vm_wire RPC is
> done on the privileged host port.

Alternatively, you could re-purpose the existing RPC `vm_wire',
changing the type of its first argument from `host_priv_t' to `host_t'
(this is backwards compatible as the privileged host control port is
also a host port), and changing the behavior slightly depending on
whether the user passed the priv port or a normal host port.

> It for now allows 64KiB mlocked memory per task (the default Linux
> value).

Isn't a per-process limit rather pointless?  I thought Linux limit is
per-user.

> Could somebody review it? (in particular on the name of the RPC)

Looks good, modulo maybe what I wrote above wrt to just using
`vm_wire'.

Oh, and why did you chose `mach4.defs' to add a new RPC?  I mean, it
doesn't really matter, the Mach API isn't properly grouped into
protocols, and there is just one huge dispatcher, but I thought we put
new definitions into `gnumach.defs'.

Cheers,
Justus