From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9BD4C433DF for ; Thu, 2 Jul 2020 14:13:52 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6CBD420780 for ; Thu, 2 Jul 2020 14:13:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6CBD420780 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 49yKp51CLbzDqSS for ; Fri, 3 Jul 2020 00:13:49 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=cmarinas@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 49yKgN1RL9zDqGT for ; Fri, 3 Jul 2020 00:08:00 +1000 (AEST) Received: from gaia (unknown [95.146.230.158]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F272720780; Thu, 2 Jul 2020 14:07:54 +0000 (UTC) Date: Thu, 2 Jul 2020 15:07:52 +0100 From: Catalin Marinas To: Anshuman Khandual Subject: Re: [PATCH V3 (RESEND) 2/3] mm/sparsemem: Enable vmem_altmap support in vmemmap_alloc_block_buf() Message-ID: <20200702140752.GF22241@gaia> References: <1592442930-9380-1-git-send-email-anshuman.khandual@arm.com> <1592442930-9380-3-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1592442930-9380-3-git-send-email-anshuman.khandual@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: x86@kernel.org, "H. Peter Anvin" , Peter Zijlstra , Dave Hansen , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ingo Molnar , Paul Mackerras , Andy Lutomirski , Borislav Petkov , Thomas Gleixner , Will Deacon , Andrew Morton , linux-arm-kernel@lists.infradead.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Jun 18, 2020 at 06:45:29AM +0530, Anshuman Khandual wrote: > There are many instances where vmemap allocation is often switched between > regular memory and device memory just based on whether altmap is available > or not. vmemmap_alloc_block_buf() is used in various platforms to allocate > vmemmap mappings. Lets also enable it to handle altmap based device memory > allocation along with existing regular memory allocations. This will help > in avoiding the altmap based allocation switch in many places. > > While here also implement a regular memory allocation fallback mechanism > when the first preferred device memory allocation fails. This will ensure > preserving the existing semantics on powerpc platform. To summarize there > are three different methods to call vmemmap_alloc_block_buf(). > > (., NULL, false) /* Allocate from system RAM */ > (., altmap, false) /* Allocate from altmap without any fallback */ > (., altmap, true) /* Allocate from altmap with fallback (system RAM) */ [...] > diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c > index bc73abf0bc25..01e25b56eccb 100644 > --- a/arch/powerpc/mm/init_64.c > +++ b/arch/powerpc/mm/init_64.c > @@ -225,12 +225,12 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, > * fall back to system memory if the altmap allocation fail. > */ > if (altmap && !altmap_cross_boundary(altmap, start, page_size)) { > - p = altmap_alloc_block_buf(page_size, altmap); > - if (!p) > - pr_debug("altmap block allocation failed, falling back to system memory"); > + p = vmemmap_alloc_block_buf(page_size, node, > + altmap, true); > + } else { > + p = vmemmap_alloc_block_buf(page_size, node, > + NULL, false); > } > - if (!p) > - p = vmemmap_alloc_block_buf(page_size, node); > if (!p) > return -ENOMEM; Is the fallback argument actually necessary. It may be cleaner to just leave the code as is with the choice between altmap and NULL. If an arch needs a fallback (only powerpc), they have the fallback in place already. I don't see the powerpc code any better after this change. I'm fine with the altmap argument though. -- Catalin