From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Weiner Subject: Re: [RFC 01/22] Generic show_mem() implementation Date: Sat, 05 Apr 2008 01:10:32 +0200 Message-ID: <87d4p5kyhj.fsf@saeurebad.de> References: <12071688283927-git-send-email-hannes@saeurebad.de> <1207168839586-git-send-email-hannes@saeurebad.de> <20080403075545.GC4125@osiris.boeblingen.de.ibm.com> <20080403124820.GA30356@uranus.ravnborg.org> <871w5nouwp.fsf@saeurebad.de> <20080403181202.GA32319@uranus.ravnborg.org> <87prt6muux.fsf@saeurebad.de> <20080404213540.GA15535@uranus.ravnborg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <20080404213540.GA15535@uranus.ravnborg.org> (Sam Ravnborg's message of "Fri, 4 Apr 2008 23:35:40 +0200") Sender: linux-kernel-owner@vger.kernel.org To: Sam Ravnborg Cc: Heiko Carstens , linux-kernel@vger.kernel.org, linux-mm@kvack.org, mingo@elte.hu, davem@davemloft.net, hskinnemoen@atmel.com, cooloney@kernel.org, starvik@axis.com, dhowells@redhat.com, ysato@users.sf.net, takata@linux-m32r.org, geert@linux-m68k.org, ralf@linux-mips.org, kyle@parisc-linux.org, paulus@samba.org, schwidefsky@de.ibm.com, lethal@linux-sh.org, jdike@addtoit.com, miles@gnu.org, chris@zankel.net, rmk@arm.linux.org.uk, tony.luck@intel.com List-Id: linux-mm.kvack.org Hi Sam, Sam Ravnborg writes: >> >> After more thinking about it, wouldn't it be better to have >> >> HAVE_ARCH_SHOW_MEM in mm/Kconfig and let archs with their own show_mem() >> >> select it? Because there are far more archs that use the generic >> >> version than those having their own. >> > >> > Positive logic is almost always simpler to grasp. >> > And the usual way to do this is to let arch's select what they >> > use. >> > We do not want to have a situation where in most cases we select >> > a generic version but in some oddball case we select to have >> > a local version. >> >> I can not follow you. Of course the arch selects what they use. But >> they should not _all_ have to be flagged with an extra select. So what >> default-value are you arguing for? > The normal pattern is to let arch select the generic implmentation they > use. > Just because the majority does use the generic version should not > make us start to use the inverse logic as in your case. > > So I want all archs that uses the generic show_mem() to > do an explicit: > > config MYARCH > select HAVE_GENERIC_SHOWMEM > > Sam What is the rationale behind this? It is not a function the arch should select at all because it is VM code. The remaining arch-specific versions are meant to be removed too. It would be like forcing all architectures to select HAVE_GENERIC_PRINTK just because one architecture oopses on printk() and needs to replace it with its own version. Hannes