Date: Mon, 10 Sep 2012 14:43:31 -0400 From: John Baldwin <jhb@freebsd.org> To: attilio@freebsd.org Cc: Konstantin Belousov <kostikbel@gmail.com>, Davide Italiano <davide@freebsd.org>, src-committers@freebsd.org, svn-src-projects@freebsd.org Subject: Re: svn commit: r238907 - projects/calloutng/sys/kern Message-ID: <201209101443.31207.jhb@freebsd.org> In-Reply-To: <CAJ-FndBNC-ZheSzJaujCSijXpVZAUEO8F6ZWHEzhFM9C=XvNgA@mail.gmail.com> References: <201207301350.q6UDobCI099069@svn.freebsd.org> <504CEAE0.704@FreeBSD.org> <CAJ-FndBNC-ZheSzJaujCSijXpVZAUEO8F6ZWHEzhFM9C=XvNgA@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sunday, September 09, 2012 10:07:18 pm Attilio Rao wrote: > On Sun, Sep 9, 2012 at 8:15 PM, John Baldwin <jhb@freebsd.org> wrote: > > On 9/9/12 11:03 AM, Attilio Rao wrote: > >> On 8/2/12, Attilio Rao <attilio@freebsd.org> wrote: > >>> On 7/30/12, John Baldwin <jhb@freebsd.org> wrote: > >> > >> [ trimm ] > >> > >>>> --- //depot/projects/smpng/sys/kern/subr_turnstile.c 2012-06-04 > >>>> 18:27:32.000000000 0000 > >>>> +++ //depot/user/jhb/lock/kern/subr_turnstile.c 2012-06-05 > >>>> 00:27:57.000000000 0000 > >>>> @@ -684,6 +684,7 @@ > >>>> if (owner) > >>>> MPASS(owner->td_proc->p_magic == P_MAGIC); > >>>> MPASS(queue == TS_SHARED_QUEUE || queue == TS_EXCLUSIVE_QUEUE); > >>>> + KASSERT(!TD_IS_IDLETHREAD(td), ("idle threads cannot block on locks")); > >>>> > >>>> /* > >>>> * If the lock does not already have a turnstile, use this thread's > >>> > >>> I'm wondering if we should also use similar checks in places doing > >>> adaptive spinning (including the TD_NO_SLEEPING check). Likely yes. > >> > >> So what do you think about this? > > > > This is isn't really good enough then. An idle thread should not > > acquire any lock that isn't a spin lock. Instead, you would be > > better off removing the assert I added above and adding an assert to > > mtx_lock(), rw_{rw}lock(), sx_{sx}lock(), lockmgr(), rm_{rw}lock() and > > all the try variants of those. > > What do you think about these then? These look good, thanks! -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201209101443.31207.jhb>