no more WITNESS errors (was: stable kqueue locking up and running on SMP)

From: Brian Fundakowski Feldman (green_at_FreeBSD.org)
Date: 04/21/04

  • Next message: Doug Rabson: "Re: no more WITNESS errors (was: stable kqueue locking up and running on SMP)" 
    To: "Brian F. Feldman" <green@FreeBSD.org>
Date: Wed, 21 Apr 2004 14:43:08 -0400

    I know everyone's tired of seeing all the e-mail on the subject, so I'll
    keep it brief ;). The kqueue fields that just happened to be stored in the
    struct filedesc have always been owned by kqueue, and now they are locked
    by kqueue, not filedesc, to become more semantically correct. Just like all
    of the rest of the things (klist, knote, kqueue, fdp->fd_kn*), the lock
    right now is just a shared, global one, and should remain so unless
    profiling proves it unnecessary.

    I would like to encourage more widespread testing. The unused and
    nearly-unimplementable-EVFILT_PROC+NOTE_TRACK is gone, but the ability to
    nest kqueues remains (and will certainly impart difficulties if locking
    is extended to separate the individual klists). I don't think there are
    any remaining issues for kqueue unless I've missed replacing some of the
    SLIST_INSERT_HEAD()/SLIST_REMOVE() calls with KLIST_INSERT()/KLIST_REMOVE().

    "Final" patch, ripe for testing/MUTEX_PROFILING, at:
    <http://69.140.204.238/~green/kqueue-giant-locking.3.patch> 

    -- 
Brian Fundakowski Feldman                           \'[ FreeBSD ]''''''''''\
  <> green@FreeBSD.org                               \  The Power to Serve! \
 Opinions expressed are my own.                       \,,,,,,,,,,,,,,,,,,,,,,\
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  • Next message: Doug Rabson: "Re: no more WITNESS errors (was: stable kqueue locking up and running on SMP)"