Date: Wed, 8 Apr 2015 19:27:46 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] nohz: make nohz_full imply isolcpus
Message-ID: <20150408172746.GK5029@twins.programming.kicks-ass.net>
References: <5522BF1E.2040606@ezchip.com>
 <1428344205-27678-1-git-send-email-cmetcalf@ezchip.com>
 <1428344205-27678-2-git-send-email-cmetcalf@ezchip.com>
 <20150408094114.GX23123@twins.programming.kicks-ass.net>
 <5525357B.2080205@ezchip.com>
 <20150408142641.GG5029@twins.programming.kicks-ass.net>
 <55254794.4070503@ezchip.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <55254794.4070503@ezchip.com>
User-Agent: Mutt/1.5.21 (2012-12-30)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 865
Lines: 19

On Wed, Apr 08, 2015 at 11:21:56AM -0400, Chris Metcalf wrote:
> Apparently the body of the commit message isn't as clear as it might be :-)
> 
> It does say the same thing, though, basically that if nohz_full DOESN'T
> imply isolcpus, that's a bad thing.  I'm happy to reword the text to avoid
> the double negative and say:
> 
>   nohz_full is only useful with isolcpus also set, since otherwise the
>   scheduler has to run periodically to try to determine whether to steal
>   work from other cores.

But you're doing the reverse! You're setting nohz_full for isolcpus, not
limiting the nohz_full mask to isolcpus.

--
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/