On Thu, Nov 27, 2014 at 10:37 AM, Alfred Perlstein <bri...@mu.org> wrote: > > On Nov 27, 2014, at 1:52 AM, Konstantin Belousov wrote: > >> On Wed, Nov 26, 2014 at 04:41:27PM -0800, Davide Italiano wrote: >>> On Mon, Aug 25, 2014 at 12:37 PM, John Baldwin <j...@freebsd.org> wrote: >>>> On Wednesday, August 20, 2014 11:00:14 AM Davide Italiano wrote: >>>>> One of my personal goals for 11 is to get rid of cloning mechanism >>>>> entirely, and pty(4) is one of the few in-kernel drivers still relying >>>>> on such mechanism. >> Why this is good thing to do ? >> >>>>> It's not possible, at least to my understanding, converting pty(4) to >>>>> cdevpriv(9) as happened with other drivers. This is mainly because we >>>>> always need a pair of devices (/dev/ptyXX and /dev/ttyXX) and >>>>> userspace loops over ptyXX and after it successfully opens it tries to >>>>> open the other one with the same suffix. So, having a single device is >>>>> not really enough. >>>>> My option, instead, is that of removing pty(4), which is nothing more >>>>> than a compatibility driver, and move pmtx(4) code somewhere else. >>>>> The main drawback of the removal of this is that it makes impossible >>>>> to run FreeBSD <= 7 jails and SSH into them. I personally don't >>>>> consider this a huge issue, in light of the fact that FreeBSD-7 has >>>>> been EOL for a long time, but I would like to hear other people >>>>> comments. >> You don't, but other people care about ABI. >> >> Besides older jails which you do not care about, there is significant >> set of programs which were coded to use Berkley' pty directly. Even >> high-profile applications like Emacs automatically selected pty(4) >> up to its previous version on FreeBSD. >> >>>>> >>>>> The code review for the proposed change can be found here: >>>>> https://reviews.freebsd.org/D659 >>>>> >>>>> If I won't get any objection I'll commit this in one week time, i.e. >>>>> August 27th. >>>> >>>> Why not just statically create the pairs in /dev? Use some loader tunable >>>> (kern.ptymax) to set a count on the number of pre-created device pairs to >>>> create and then just explicitly create them in the mod_event handler? It >>>> could default to 100 or so. >>>> >>> >>> Done, thank you for the suggestion, John. >>> >>> root@maxwell:/home/davide # kldload pty >>> root@maxwell/home/davide # sysctl -a |grep pty >>> kern.tty_pty_warningcnt: 1 >>> kern.npty: 32 >>> debug.softdep.emptyjblocks: 0 >>> >>> root@maxwell:/home/davide # ls /dev/pty* >>> /dev/ptyl0 /dev/ptyl2 /dev/ptyl4 /dev/ptyl6 /dev/ptyl8 /dev/ptyla >>> /dev/ptylc /dev/ptyle /dev/ptylg /dev/ptyli /dev/ptylk /dev/ptylm >>> /dev/ptylo /dev/ptylq /dev/ptyls /dev/ptylu >>> /dev/ptyl1 /dev/ptyl3 /dev/ptyl5 /dev/ptyl7 /dev/ptyl9 /dev/ptylb >>> /dev/ptyld /dev/ptylf /dev/ptylh /dev/ptylj /dev/ptyll /dev/ptyln >>> /dev/ptylp /dev/ptylr /dev/ptylt /dev/ptylv >>> >>> https://reviews.freebsd.org/D1238 for review. >>> I hope anybody that raised concerns about the previous patch can try >>> this new one. >> >> I do not see why dev_clone event makes your so unhappy. I object against >> removal of it (and this is what you are aiming at, it seems). It provides >> useful functionality, which is not substituted by anything cdevpriv(9) >> can provide. >> >> My only hope is that you are confusing dev_clone event and a library of >> clone_create(9)/clone_cleanup(9)/dev_stdclone(9) functions. The former >> is needed and cannot be replaced by cdevpriv(9). >> >> The later is clumsy and never was used properly. My opinion is that it >> is impossible to use properly. There are five uses of that in tree left, >> and it seems that removing them worth cleaning of buggy by design and >> undocumented KPI. >> >> Really big and complicated target is the hand-written timeout-based (?!) >> custom cloning code in snd(4). I believe it _can_ be converted to >> cdevpriv(9). >
All right, I dropped the review and reverted my branch. Thanks for the comment(s). -- Davide "There are no solved problems; there are only problems that are more or less solved" -- Henri Poincare _______________________________________________ email@example.com mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"