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 A0BBBC433E0 for ; Fri, 3 Jul 2020 06:38:26 +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 C243020772 for ; Fri, 3 Jul 2020 06:38:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C243020772 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 49ylf827kmzDqjJ for ; Fri, 3 Jul 2020 16:38:24 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=anshuman.khandual@arm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 49ylWT36v7zDqwT for ; Fri, 3 Jul 2020 16:32:35 +1000 (AEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id ADD9431B; Thu, 2 Jul 2020 23:32:32 -0700 (PDT) Received: from [10.163.85.168] (unknown [10.163.85.168]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B20083F73C; Thu, 2 Jul 2020 23:32:27 -0700 (PDT) Subject: Re: [PATCH V3 (RESEND) 2/3] mm/sparsemem: Enable vmem_altmap support in vmemmap_alloc_block_buf() To: Catalin Marinas References: <1592442930-9380-1-git-send-email-anshuman.khandual@arm.com> <1592442930-9380-3-git-send-email-anshuman.khandual@arm.com> <20200702140752.GF22241@gaia> From: Anshuman Khandual Message-ID: Date: Fri, 3 Jul 2020 12:02:11 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20200702140752.GF22241@gaia> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 07/02/2020 07:37 PM, Catalin Marinas wrote: > 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. Okay. Will drop 'fallback' from vmemmap_alloc_block_buf() and update the callers. There will also be a single change in the subsequent patch i.e vmemmap_alloc_block_buf(PMD_SIZE, node, altmap).