linux-kernel - Re: [RFC][PATCH 7/7] kref: Implement using refcount

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Message-ID: <20161115130315.GA12957@gmail.com>
Date:   Tue, 15 Nov 2016 14:03:15 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     gregkh@...uxfoundation.org, keescook@...omium.org,
        will.deacon@....com, elena.reshetova@...el.com, arnd@...db.de,
        tglx@...utronix.de, hpa@...or.com, dave@...gbits.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC][PATCH 7/7] kref: Implement using refcount_t


* Peter Zijlstra <peterz@...radead.org> wrote:

> On Tue, Nov 15, 2016 at 11:03:59AM +0100, Ingo Molnar wrote:
> > > Should I also make a CONFIG knob that implements refcount_t with the
> > > 'normal' atomic_t primitives?
> > 
> > I'd suggest doing the saturation/safe-wrap semantics only for now (i.e. the 
> > current patch, split into two perhaps), and reconsider if there's any complaints?
> > 
> > > And possibly another knob to toggle the BUG()s into WARN()s. With the
> > > full saturation semantics WARN() is a lot safer and will not corrupt
> > > kernel state as much.
> > 
> > I'd suggest changing it to a WARN() straight away, no extra knobs.
> 
> OK, a little like so then? Note that the overflow tests went away
> because increments guarantee we saturate before we overflow.

Looks good to me!

Thanks,

	Ingo