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From: compudj@krystal.dyndns.org (Mathieu Desnoyers)
Subject: [ltt-dev] [PATCH 2/2] introduce uatomic_and and uatomic_or
Date: Fri, 12 Nov 2010 07:38:57 -0500	[thread overview]
Message-ID: <20101112123856.GA31489@Krystal> (raw)
In-Reply-To: <20101112123018.GB30826@Krystal>

* Mathieu Desnoyers (compudj at krystal.dyndns.org) wrote:
> * Paolo Bonzini (pbonzini at redhat.com) wrote:
> > On 11/12/2010 01:24 PM, Paolo Bonzini wrote:
> >> Should I rename uatomic_add to uatomic_xchg_add too (I prefer this name
> >> to uatomic_return_add)?
> >
> > Uh, uatomic_add returns void actually.  Then returning void from  
> > uatomic_{and,or} is indeed more consistent.
> 
> Ah! I knew we'd find the culprit!! ;-)

BTW, I'd be fine with adding:

uatomic_and/uatomic_or (returning void)

But I wonder if, on any architecture, there is a significantly better
way to implement:

uatomic_xchg_add/uatomic_xchg_or (returning the old value)

other than using a cmpxchg() underneath ? If not, then creating this
extra primitive would be pretty much useless.

Thanks,

Mathieu


-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com



  reply	other threads:[~2010-11-12 12:38 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-12  8:57 [ltt-dev] [PATCH 0/2] Add uatomic_and and uatomic_or to uatomic library Paolo Bonzini
2010-11-12  8:57 ` [ltt-dev] [PATCH 1/2] use generic-size operations for common implementation of atomic ops Paolo Bonzini
2010-11-12 12:04   ` Mathieu Desnoyers
2010-11-12  8:57 ` [ltt-dev] [PATCH 2/2] introduce uatomic_and and uatomic_or Paolo Bonzini
2010-11-12 12:08   ` Mathieu Desnoyers
2010-11-12 12:13     ` Paolo Bonzini
2010-11-12 12:19       ` Mathieu Desnoyers
2010-11-12 12:24         ` Paolo Bonzini
2010-11-12 12:27           ` Paolo Bonzini
2010-11-12 12:30             ` Mathieu Desnoyers
2010-11-12 12:38               ` Mathieu Desnoyers [this message]
2010-11-12 14:39                 ` Paolo Bonzini
2010-11-12 12:29           ` Mathieu Desnoyers
2010-11-12 14:39             ` Paolo Bonzini
2010-11-12 12:15     ` Mathieu Desnoyers

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