Forgot the references, sorry about that:
[1] http://wiki.hiit.fi/display/psirpcode/Blackhawk
[2] www.psirp.org
--Pekka Nikander
On 2010-08 -30, at 15:54 , Pekka Nikander wrote:
> We are trying to interface the Blackhawk memory-sharing
> publish/subscribe-based IPC system [1], developed in the PSIRP project [2],
> with Click, initially at the user level.
>
> One particular problem that we are facing is that the Blackhawk IPC is
> heavily based on using EVFILT_VNODE kevents, even extending them at the
> kernel side. Now, Click as it is currently only supports EVFILT_READ and
> EVFILT_WRITE kevents. While it would be possible to change Blackhawk to
> support them, too, in addition to EVFILT_VNODE kevents, it would not be
> sufficient since Blackhawk also uses the kevent->udata field for houskeeping,
> and Click's Master class does not support it.
>
> Thus, we have ended up looking at how to extend the Master class to have
> better kevent support, in a way that would also benefit others and not only
> our project. Right now we have made some minimal changes to the Master
> class, allowing it to be more easily subclassed, and created a subclass of
> Master, called KqueueMaster. However, this approach has the problem that we
> also need to modify the click.cc itself, to instantiate a KqueueMaster
> instead of the regular Master, an approach that I don't consider very
> elegant. It works for now, but it is not nice.
>
> Hence, I'm looking for advice and opinions on how to approach the issue. Our
> initial patch (the master.{hh,cc} part) included below.
>
> --Pekka Nikander
>
> diff --git a/include/click/master.hh b/include/click/master.hh
> index f0cc360..e2c4861 100644
> --- a/include/click/master.hh
> +++ b/include/click/master.hh
> @@ -69,6 +69,15 @@ class Master { public:
> static volatile sig_atomic_t signals_pending;
> #endif
>
> +#if CLICK_KQUEUE_MASTER
> + protected:
> + void select_lock_acquire();
> + void select_lock_release();
> + void register_kqueue(int fd, short filter, u_int fflags,
> + intptr_t d, void *ud);
> + virtual void call_kqueued(int fd, struct kevent *event);
> +#endif
> +
> private:
>
> // stick _timer_expiry here so it will most likely fit in a cache line,
> @@ -360,5 +369,19 @@ Element::master() const
> return _router->master();
> }
>
> +#if CLICK_KQUEUE_MASTER
> +inline void Master::select_lock_acquire() {
> + _select_lock.acquire();
> +}
> +
> +inline void Master::select_lock_release() {
> + _select_lock.release();
> +}
> +
> +inline void Master::call_kqueued(int /*fd*/, struct kevent */*event*/) {
> + // Do nothing
> +}
> +#endif
> +
> CLICK_ENDDECLS
> #endif
>
> diff --git a/lib/master.cc b/lib/master.cc
> index 95ee585..1c80282 100644
> --- a/lib/master.cc
> +++ b/lib/master.cc
> @@ -535,6 +535,26 @@ Master::run_timers()
>
> #if CLICK_USERLEVEL
>
> +# if CLICK_KQUEUE_MASTER
> +void
> +Master::register_kqueue(int fd, short filter, u_int fflags, intptr_t d, void
> *ud) {
> + if (_kqueue >= 0) {
> + // Add events to the kqueue
> + struct kevent kev[2];
> + int nkev = 0;
> + EV_SET(&kev[nkev], fd, filter, EV_ADD, fflags, d, ud);
> + nkev++;
> + int r = kevent(_kqueue, &kev[0], nkev, 0, 0, 0);
> + if (r < 0) {
> + // Not all file descriptors are kqueueable. So if we encounter
> + // a problem, fall back to select() or poll().
> + close(_kqueue);
> + _kqueue = -1;
> + }
> + }
> +}
> +# endif
> +
> namespace {
> enum { SELECT_READ = Element::SELECT_READ, SELECT_WRITE =
> Element::SELECT_WRITE };
> }
> @@ -560,6 +580,14 @@ Master::register_select(int fd, bool add_read, bool
> add_write)
> _pollfds[pi].events |= POLLOUT;
>
> #if HAVE_USE_KQUEUE
> +# if CLICK_KQUEUE_MASTER
> + if (add_read) {
> + register_kqueue(fd, EVFILT_READ, 0, 0, EV_SET_UDATA_CAST ((intptr_t)
> 0));
> + }
> + if (add_write) {
> + register_kqueue(fd, EVFILT_WRITE, 0, 0, EV_SET_UDATA_CAST ((intptr_t)
> 0));
> + }
> +# else
> if (_kqueue >= 0) {
> // Add events to the kqueue
> struct kevent kev[2];
> @@ -580,6 +608,7 @@ Master::register_select(int fd, bool add_read, bool
> add_write)
> _kqueue = -1;
> }
> }
> +# endif
> #endif
> #if !HAVE_POLL_H || HAVE_USE_SELECT
> @@ -839,6 +868,10 @@ Master::run_selects_kqueue(RouterThread *thread, bool
> more_tasks)
> mask |= Element::SELECT_READ;
> else if (p->filter == EVFILT_WRITE)
> mask |= Element::SELECT_WRITE;
> +# if CLICK_KQUEUE_MASTER
> + else
> + call_kqueued(fd, p);
> +# endif
> call_selected(fd, mask);
> }
> }
>
>
> _______________________________________________
> click mailing list
> click@amsterdam.lcs.mit.edu
> https://amsterdam.lcs.mit.edu/mailman/listinfo/click
_______________________________________________
click mailing list
click@amsterdam.lcs.mit.edu
https://amsterdam.lcs.mit.edu/mailman/listinfo/click
