From: Al Viro <viro@ZenIV.linux.org.uk>
To: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>
Subject: Re: RT, what to do about up/down_read_non_owner()
Date: Mon, 6 Jun 2016 20:24:46 +0100 [thread overview]
Message-ID: <20160606192446.GE14480@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1465206604.6397.18.camel@gmail.com>
On Mon, Jun 06, 2016 at 11:50:04AM +0200, Mike Galbraith wrote:
> (CCs Al, who knows, maybe he'll make them go *poof*)
>
> > > > In v4.7, Al added those buggers to NFS. BCACHE is disabled in RT
> > > > because of same.. but that's a somewhat suboptimal solution for
> > > > something as widely used as NFS.
> > > >
> > > > Suggestions? I reverted the offending commit to get 4.7-rt up and
> > > > running, but that's not gonna fly long term.
> > >
> > > This API should be avoided according to the comment and completions
> > > should be used. I am for removal of those. Were the locking people okay
> > > with this change in the first place or did this just sneak in?
> >
> > It just snuck in. Al reworked sillyunlink, whacking the wait_event()
> > stuff that was there, using annoying $subject instead.
It's more than just wait_event() crap being killed (and crap it certainly
was). The situation is pretty much the same as with bcache; we don't want
readers to stick around until the initiated action has been completed.
What exactly is RT problem, just to be sure to avoid reproducing exact same
issue in the replacement?
next prev parent reply other threads:[~2016-06-06 19:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-05 6:57 RT, what to do about up/down_read_non_owner() Mike Galbraith
2016-06-06 7:49 ` Sebastian Andrzej Siewior
2016-06-06 9:07 ` Mike Galbraith
2016-06-06 9:50 ` Mike Galbraith
2016-06-06 19:24 ` Al Viro [this message]
2016-06-07 2:39 ` Mike Galbraith
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