Em Mon, Sep 08, 2014 at 05:10:17PM +0200, Jiri Olsa escreveu: > On Mon, Sep 08, 2014 at 11:33:17AM -0300, Arnaldo Carvalho de Melo wrote: > > > IMO it's more clear to poll pm all event FDs.. and now with the > > > case Adrian described it seems necessary anyway
> > I would have to check why was that we were polling just the one where > > the mmap is done, I don't recall being the one to do it, probably who > > did it thought that since the ring buffer is there, it was enough (and > > possibly scaled better, dunno) to do the polling in just one of them. > for read notification it's ok to poll just for one event, because they > all share same ringbuffer and perf_poll checks if there's ANY new data > for the hup notification I think we need to poll all of them Yeah, I'm convinced of this, I'm working on a patch to make it look at all file descriptors at poll time. I'm doing it on top of a patch that will close the mmap when it gets a POLLHUP, as discussed recently on this thread, in a response I gave to Adrian. But since multiple fds share an mmap, we can only close that mmap when all fds are HUPed, i.e. we need to reference count struct perf_mmap, which is what I am doing. I.e. the fist mmaps and sets perf_mmap.nfds to 1, the next one, just after doing that PERF_EVENT_IOC_SET_OUTPUT will bump perf_mmap.nfds, unmap gets replaced by mmap_put, that decs and calls munmap when it hits zero, yadda, yadda. - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
