Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755616Ab2F1RuW (ORCPT ); Thu, 28 Jun 2012 13:50:22 -0400 Received: from mail-qc0-f174.google.com ([209.85.216.174]:41957 "EHLO mail-qc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751704Ab2F1RuV (ORCPT ); Thu, 28 Jun 2012 13:50:21 -0400 Date: Thu, 28 Jun 2012 13:50:16 -0400 (EDT) From: Nicolas Pitre To: Russell King - ARM Linux cc: Dave Martin , Minchan Kim , Catalin Marinas , Chanho Min , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Jongsung Kim , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] [RESEND] arm: limit memblock base address for early_pte_alloc In-Reply-To: <20120628090827.GH19026@n2100.arm.linux.org.uk> Message-ID: References: <1338880312-17561-1-git-send-email-minchan@kernel.org> <20120627161224.GB2310@linaro.org> <20120628090827.GH19026@n2100.arm.linux.org.uk> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1572 Lines: 42 On Thu, 28 Jun 2012, Russell King - ARM Linux wrote: > Err, I don't think you understand what's going on here. > > The sequence is: > > 1. setup the initial mappings so we can run the kernel in virtual space. > 2. provide the memory areas to memblock > 3. ask the platform to reserve whatever memory it wants from memblock > [this means using memblock_reserve or arm_memblock_steal). The > reserved memory is *not* expected to be mapped at this point, and is > therefore inaccessible. > 4. Setup the lowmem mappings. I do understand that pretty well so far. > And when we're setting up the lowmem mappings, we do *not* expect to > create any non-section page mappings, which again means we have no reason > to use the memblock allocator to obtain memory that we want to immediately > use. And why does this have to remain so? > So I don't know where you're claim of being "fragile" is coming from. It doesn't come from anything you've described so far. It comes from those previous attempts at lifting this limitation. I think that my proposal is much less fragile than the other ones. > What is fragile is people wanting to use arm_memblock_steal() without > following the rules for it I layed down. What about enhancing your rules if the technical limitations they were based on are lifted? Nicolas -- 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/