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=-4.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 C2561C433E0 for ; Fri, 3 Jul 2020 10:41:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F3FF20723 for ; Fri, 3 Jul 2020 10:41:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ellerman.id.au header.i=@ellerman.id.au header.b="R6OndPXL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726276AbgGCKlY (ORCPT ); Fri, 3 Jul 2020 06:41:24 -0400 Received: from bilbo.ozlabs.org ([203.11.71.1]:43731 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726039AbgGCKlY (ORCPT ); Fri, 3 Jul 2020 06:41:24 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 49ys2R4MTvz9sQt; Fri, 3 Jul 2020 20:41:19 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ellerman.id.au; s=201909; t=1593772881; bh=ouQdbcbhXEsmtXFYa0vga5m4RkRqU+lSip6svPkAoWE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=R6OndPXLKtiDiQ1Yg6qZjpgHLC6/QS2AlJZYtOzMgFSeYNh6Sx3B0ltJCzh7sjte5 WiiVS0RAL5X390ALRNp7CDkU1RVQeSH9Wca2ibJ08WXyPDBnyYO+Gxoy56H8T0H24A F6WMbq5RKm4waWWNoG6ZJkS8Z04QD4Qfen0kPPO+o9GKjqMlrQM4oL+Hip9uWVFMld UPez+VVedhg6+MIFlsUQ+LqzA6fjTMk4Lbg8v+KsyVDGxyvtiP2F5mRej5ntf0lZ9k 3JqKlIL/mXbyppKeQNjGxRorukCOGXpRzvqKB7CGr+jE5Hsx4Z3fp9XtqzVesL+Bm3 JD0xFqCJG+Szw== From: Michael Ellerman To: Catalin Marinas , Anshuman Khandual Cc: linux-mm@kvack.org, Will Deacon , Benjamin Herrenschmidt , Paul Mackerras , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Andrew Morton , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V3 (RESEND) 2/3] mm/sparsemem: Enable vmem_altmap support in vmemmap_alloc_block_buf() In-Reply-To: <20200702140752.GF22241@gaia> References: <1592442930-9380-1-git-send-email-anshuman.khandual@arm.com> <1592442930-9380-3-git-send-email-anshuman.khandual@arm.com> <20200702140752.GF22241@gaia> Date: Fri, 03 Jul 2020 20:43:33 +1000 Message-ID: <87blkw7uay.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Catalin Marinas writes: > 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. Yeah I agree. cheers