Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761907AbZCYOR3 (ORCPT ); Wed, 25 Mar 2009 10:17:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750915AbZCYORS (ORCPT ); Wed, 25 Mar 2009 10:17:18 -0400 Received: from hera.kernel.org ([140.211.167.34]:57670 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751898AbZCYORR (ORCPT ); Wed, 25 Mar 2009 10:17:17 -0400 Message-ID: <49CA3C2C.5030702@kernel.org> Date: Wed, 25 Mar 2009 23:14:04 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Martin Schwidefsky CC: mingo@elte.hu, 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 Subject: Re: [GIT RFC] percpu: use dynamic percpu allocator as the default percpu allocator 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> In-Reply-To: <20090325150035.541e707a@skybase> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Wed, 25 Mar 2009 14:14:08 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1314 Lines: 35 Martin Schwidefsky wrote: > On Wed, 25 Mar 2009 20:51:31 +0900 > Tejun Heo wrote: > >>> With your patches and a RELOC_HIDE version that uses the GOTENT >>> indirection the kernel won't compile because the "X" constraint for >>> the GOTENT access needs a symbol and there are quite a few users that >>> pass a pointer. I do not see a simple solution for that problem yet. >> Ah... okay. Now I get it. It wasn't expecting variables there. How >> about doing the following? >> >> #define SHIFT_PERCPU_PTR(ptr, offset) (({ \ >> if (__builtin_constant_p(ptr)) \ >> do GOTENT trick; \ >> else \ >> RELOC_HIDE(); \ >> })) > > That doesn't work because __builtin_constant_p is false for variable > symbols. I would need a __builtin_symbol_p but that doesn't exist. Right, I somehow always get confused about the two. Eh... Not easy. I think alpha might have the same problem too. I suppose we'll have to make the legacy allocator available for alpha and s390 for the time being. I'll get to that. Thanks. -- tejun -- 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/