Subject: Re: [PATCH 0/4] RCU: various merge candidates
From: Arjan van de Ven <arjan@infradead.org>
To: dipankar@in.ibm.com
Cc: Paul E McKenney <paulmck@us.ibm.com>, Ingo Molnar <mingo@elte.hu>,
       Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org
In-Reply-To: <20060828162904.GG3325@in.ibm.com>
References: <20060828160845.GB3325@in.ibm.com>
	 <1156781748.3034.212.camel@laptopd505.fenrus.org>
	 <20060828162904.GG3325@in.ibm.com>
Content-Type: text/plain
Organization: Intel International BV
Date: Mon, 28 Aug 2006 18:33:09 +0200
Message-Id: <1156782789.3034.216.camel@laptopd505.fenrus.org>
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1289
Lines: 36

On Mon, 2006-08-28 at 21:59 +0530, Dipankar Sarma wrote:
> On Mon, Aug 28, 2006 at 06:15:48PM +0200, Arjan van de Ven wrote:
> > On Mon, 2006-08-28 at 21:38 +0530, Dipankar Sarma wrote:
> > > This patchset consists of various merge candidates that would
> > > do well to have some testing in -mm. This patchset breaks
> > > out RCU implementation from its APIs to allow multiple
> > > implementations, 
> > 
> > 
> > can you explain why we would want multiple RCU implementations?
> > Isn't one going to be plenty already?
> 
> Hi Arjan,
> 
> See this for a background - http://lwn.net/Articles/129511/
> 
> Primarily, rcupreempt allows read-side critical sections to
> be preempted unline classic RCU currently in mainline. It is
> also a bit more aggressive in terms of grace periods by counting
> the number of readers as opposed to periodic checks in classic
> RCU.
> 

hi,

thanks for the explenation, this for sure explains one half of the
equation; the other half is ... "why do we not always want this"?

Greetings,
   Arjan van de Ven

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/