From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pbcl.net (pbcl.net [159.69.221.92]) by mx.groups.io with SMTP id smtpd.web11.1346.1591132526296159072 for ; Tue, 02 Jun 2020 14:15:26 -0700 Authentication-Results: mx.groups.io; dkim=missing; spf=pass (domain: pbcl.net, ip: 159.69.221.92, mailfrom: pb@pbcl.net) Received: from pb by pbcl.net with local (Exim 4.92) (envelope-from ) id 1jgEFo-0004Ts-CQ; Tue, 02 Jun 2020 23:15:24 +0200 Date: Tue, 2 Jun 2020 23:15:24 +0200 From: "Phil Blundell" To: Richard Purdie Cc: Rasmus Villemoes , openembedded-core@lists.openembedded.org, Martin Jansa , Khem Raj , Andreas Oberritter Subject: Re: [OE-core] [PATCH v3] glibc: move ld.so.conf back to main package Message-ID: <20200602211524.GC2207@pbcl.net> References: <1614B0E5E96C4272.14405@lists.openembedded.org> <20200602121722.32623-1-rasmus.villemoes@prevas.dk> <20200602200008.GB2207@pbcl.net> <24a52dc42bb9eb49e2f8802a3c7558859160de18.camel@linuxfoundation.org> MIME-Version: 1.0 In-Reply-To: <24a52dc42bb9eb49e2f8802a3c7558859160de18.camel@linuxfoundation.org> User-Agent: Mutt/1.10.1 (2018-07-13) Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Jun 02, 2020 at 09:17:44PM +0100, Richard Purdie wrote: > I understand the concern, I am a little torn on this as adding in too > many different controls and options complicates the test matrix and > makes things harder for users. > > You're effectively suggesting a new DISTRO_FEATURE to control this? or > maybe better, perhaps a glibc PACKAGECONFIG? Yes, right. I don't think it need be a DISTRO_FEATURE because nothing outside glibc needs to care. Here are the scenarios that I think matter, ordered from simplest to most complex: 1. Immutable filesystem, every library installed in the place where ld.so would first look for it anyway (i.e. everything in {/usr}/lib). In this case, we don't want ldconfig (because it can never do anything useful), we don't want ld.so.cache and we don't want ld.so.conf because they would cause ld.so to do extra file loads and computation but end up with the same result that it would anyway. 2. Immutable filesystem but some libraries are in places that ld.so wouldn't automatically know about. In this case we do want ld.so.conf and ld.so.cache, but we still don't want ldconfig. 3. Mutable filesystem where arbitrary binaries can be installed in arbitrary places. It's probably debatable whether ldconfig is needed in all these cases, but clearly it's needed in some and I think at this point it can be left to a DISTRO decision how exactly they want to optimize things. I think right now oe-core supports #1 and #3. The proposed patch seems to be aimed at #2, which is a completely valid usecase, but my concern is that we don't want to pessimize #1 in the process. There is a whole parallel discussion to be had about the merits or otherwise of ld.so's hwcaps mechanism. meta-micro has been carrying a patch for about a decade to turn all that stuff off, on the grounds that it's just a loss on any kind of embedded environment. Maybe I should make some effort to get it upstream as an option. p.