Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761580AbZDANzf (ORCPT ); Wed, 1 Apr 2009 09:55:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756622AbZDANzF (ORCPT ); Wed, 1 Apr 2009 09:55:05 -0400 Received: from smtp.ultrahosting.com ([74.213.174.254]:42412 "EHLO smtp.ultrahosting.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765404AbZDANzD (ORCPT ); Wed, 1 Apr 2009 09:55:03 -0400 Date: Wed, 1 Apr 2009 09:49:25 -0400 (EDT) From: Christoph Lameter X-X-Sender: cl@qirst.com To: Tejun Heo cc: Ingo Molnar , Martin Schwidefsky , rusty@rustcorp.com.au, tglx@linutronix.de, x86@kernel.org, linux-kernel@vger.kernel.org, hpa@zytor.com, Paul Mundt , rmk@arm.linux.org.uk, starvik@axis.com, ralf@linux-mips.org, davem@davemloft.net, cooloney@kernel.org, kyle@mcmartin.ca, matthew@wil.cx, grundler@parisc-linux.org, takata@linux-m32r.org, benh@kernel.crashing.org, rth@twiddle.net, ink@jurassic.park.msu.ru, heiko.carstens@de.ibm.com, Linus Torvalds , Nick Piggin Subject: Re: [PATCH UPDATED] percpu: use dynamic percpu allocator as the default percpu allocator In-Reply-To: <49D2B209.9060000@kernel.org> Message-ID: References: <1236671631-9305-1-git-send-email-tj@kernel.org> <20090316190132.7965a49a@skybase> <49C300D8.5080204@kernel.org> <49C8FAC4.6060508@kernel.org> <20090325122738.42d105b7@skybase> <49CA1AC3.9080908@kernel.org> <20090325150035.541e707a@skybase> <49CA3C2C.5030702@kernel.org> <49D099F0.3000807@kernel.org> <20090330114938.GB10070@elte.hu> <49D2B209.9060000@kernel.org> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 911 Lines: 19 On Wed, 1 Apr 2009, Tejun Heo wrote: > > 1. Lot of unnecessary use of __read_mostly for local static variables that > > are not on the hotpath. Patch follows in this message. > > Hmmm... Those are basically read-only vars once initialization is > complete. IIUC, __read_mostly just puts the tagged variables into a > separate segment so that they don't have to worry about cacheline > bouncing. Is there any reason to remove __read_mostly? Or is it just > that it's mostly superflous? Yes its better for the variables to be all together if its not on hot cache paths. And its better to keep the __read_mostly segment reserved for frequently accessed variables. -- 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/