From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752253AbbE1IN1 (ORCPT ); Thu, 28 May 2015 04:13:27 -0400 Received: from lb2-smtp-cloud2.xs4all.net ([194.109.24.25]:46402 "EHLO lb2-smtp-cloud2.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751372AbbE1INS (ORCPT ); Thu, 28 May 2015 04:13:18 -0400 Message-ID: <1432800791.8508.15.camel@x220> Subject: Re: [PATCH 2/1] init/Kconfig: Split expert menu into a separate file, init/Kconfig.expert From: Paul Bolle To: Josh Triplett Cc: Ingo Molnar , Andrew Morton , "Paul E. McKenney" , Michal Hocko , Vladimir Davydov , Johannes Weiner , Geert Uytterhoeven , Andy Lutomirski , Bertrand Jacquin , "Luis R. Rodriguez" , Iulia Manda , Pranith Kumar , Clark Williams , Mel Gorman , Randy Dunlap , linux-kernel@vger.kernel.org Date: Thu, 28 May 2015 10:13:11 +0200 In-Reply-To: <1431382517.2398.127.camel@x220> References: <20150511181327.GA1884@jtriplet-mobl1> <20150511202301.GA11897@jtriplet-mobl1> <1431381021.2398.111.camel@x220> <20150511220419.GB15791@jtriplet-mobl1> <1431382517.2398.127.camel@x220> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-4.fc20) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Yes, this patch is superseded by your series starting at https://lkml.org/lkml/2015/5/14/447 . But I wanted to jot this down somewhere.] On Tue, 2015-05-12 at 00:15 +0200, Paul Bolle wrote: > On Mon, 2015-05-11 at 15:04 -0700, Josh Triplett wrote: > > On Mon, May 11, 2015 at 11:50:21PM +0200, Paul Bolle wrote: > > > On Mon, 2015-05-11 at 13:23 -0700, Josh Triplett wrote: > > > > +config KALLSYMS_ALL > > > > + bool "Include all symbols in kallsyms" > > > > > > (For some reason this entry doesn't have if EXPERT but it seems to > > > behave as expected. Odd.) > > > > Because it depends on KALLSYMS. Magic! > > Welcome to the land of Kconfig! It's even more subtle (at least currently, ie before this patch is applied). KALLSYMS_ALL's prompt doesn't depend on EXPERT. KALLSYMS's prompt does. For some reason, perhaps because KALLSYMS_ALL depends on KALLSYMS, this makes both entries visible under EXPERT's menu even if EXPERT is _not_ set. But, in contrast to BPF_SYSCALL, this doesn't influence the following symbols that do have a prompt that depends on EXPERT. Adding "if EXPERT" to the prompt of KALLSYMS_ALL does hide that symbol _and_ KALLSYMS (when EXPERT is not set, of course). (This may be documented, or clearly commented in the code. I didn't check.) > > > > + depends on DEBUG_KERNEL && KALLSYMS > > > > + help > > > > + Normally kallsyms only contains the symbols of functions for nicer > > > > + OOPS messages and backtraces (i.e., symbols from the text and inittext > > > > + sections). This is sufficient for most cases. And only in very rare > > > > + cases (e.g., when a debugger is used) all symbols are required (e.g., > > > > + names of variables from the data sections, etc). > > > > + > > > > + This option makes sure that all symbols are loaded into the kernel > > > > + image (i.e., symbols from all sections) in cost of increased kernel > > > > + size (depending on the kernel configuration, it may be 300KiB or > > > > + something like this). > > > > + > > > > + Say N unless you really need all symbols. Thanks, Paul Bolle