Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752649Ab3HVKUm (ORCPT ); Thu, 22 Aug 2013 06:20:42 -0400 Received: from mail-qc0-f176.google.com ([209.85.216.176]:56021 "EHLO mail-qc0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752552Ab3HVKUk (ORCPT ); Thu, 22 Aug 2013 06:20:40 -0400 MIME-Version: 1.0 In-Reply-To: <20130822100008.2669b0d9@armhf> References: <20130820120105.55a4c0ce@armhf> <20130822100008.2669b0d9@armhf> From: Grant Likely Date: Thu, 22 Aug 2013 11:20:19 +0100 X-Google-Sender-Auth: 3cH-_hwMq4IWv4ngj2YOq2XXn5k Message-ID: Subject: Re: [PATCH] of: reduce the number of PROBE_DEFERs To: Jean-Francois Moine Cc: Rob Herring , "devicetree@vger.kernel.org" , Linux Kernel Mailing List , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1651 Lines: 37 On Thu, Aug 22, 2013 at 9:00 AM, Jean-Francois Moine wrote: > On Tue, 20 Aug 2013 11:13:24 +0100 > Grant Likely wrote: > >> On Tue, Aug 20, 2013 at 11:01 AM, Jean-Francois Moine wrote: >> > This patch populates the platform from the device tree into two steps: >> > the first step creates the nodes that are referenced by a phandle, >> > the second step creates the other nodes. >> > >> > This permits to reduce the number of PROBE_DEFERs. >> > >> > Signed-off-by: Jean-Francois Moine >> > --- >> > A better way to reduce probe deferral could be sorting the nodes >> > according to their phandle level in the DT blob at compilation time ... >> >> Have you got measurements or statistics that show this making a >> difference? I suspect you'll find for boot time it will have little to >> no affect since the device driver probe order is more closely related >> to the kernel link order than the order that devices were registered. > > With the device tree and most drivers as modules, the kernel link order > does not matter. > > I admit that the gain may be small: I just get none or just one probe > deferral instead of 3 on my cubox with this patch. If you've only got 3 probe deferrals, then is this really an issue worth complicating the code over? I'd like to see a more significant impact before taking this step. g. -- 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/