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=-12.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 24668C4363D for ; Tue, 6 Oct 2020 03:38:15 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 AD45C208A9 for ; Tue, 6 Oct 2020 03:38:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="CGhzCZfX" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AD45C208A9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=/rz99iC8bXWltibJMkUxmmxM3BHORHzR7L0wEqrmat4=; b=CGhzCZfXDyPX0axA21r3uz++4 96LsWzj/WjPg0Va58lzCIvfJ6t8aaiiPq8gTa094Rw29SQlCIhbYGEWkiLED+THwXnmHeMmR/3KUu PsUphpdXMB4NG80gtveFSW9Oh4hQNBua5vmr8+blDZA17CGtG+uNc0Cp6AemgNn0zVDrUaaD2iyem 0exvAjJsdRsLHG+hMCv3FZBfeEHGOUVRelol2pq0CcL7Ik0GLRJR3Szl2ZkFkUufac9dt+YKhTjex EjNhxyChx7t5Zww0VVTWpt85s1D+nCWpixLtVYOvoH0BQ00saMJLBis/Ck7p+opOEe5r8fz/zsmaT b2/mba+WQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kPdme-0003B8-Vy; Tue, 06 Oct 2020 03:37:01 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kPdmc-0003Aa-GC for linux-arm-kernel@lists.infradead.org; Tue, 06 Oct 2020 03:36:59 +0000 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 7DDDB113E; Mon, 5 Oct 2020 20:36:54 -0700 (PDT) Received: from [10.163.74.99] (unknown [10.163.74.99]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7045B3F71F; Mon, 5 Oct 2020 20:36:51 -0700 (PDT) Subject: Re: [PATCH v3] arm64/mm: add fallback option to allocate virtually contiguous memory To: Sudarshan Rajagopalan , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <9e6178d2828e9c36275487263c5842c688e5b731.1601582954.git.sudaraja@codeaurora.org> From: Anshuman Khandual Message-ID: <49dd60a7-25f4-8dc1-b905-088dff2a84fb@arm.com> Date: Tue, 6 Oct 2020 09:06:20 +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: <9e6178d2828e9c36275487263c5842c688e5b731.1601582954.git.sudaraja@codeaurora.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201005_233658_587577_8196D4C6 X-CRM114-Status: GOOD ( 23.30 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Will Deacon , David Hildenbrand , Catalin Marinas , Steven Price , Andrew Morton , Logan Gunthorpe Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 10/02/2020 01:46 AM, Sudarshan Rajagopalan wrote: > When section mappings are enabled, we allocate vmemmap pages from physically > continuous memory of size PMD_SIZE using vmemmap_alloc_block_buf(). Section > mappings are good to reduce TLB pressure. But when system is highly fragmented > and memory blocks are being hot-added at runtime, its possible that such > physically continuous memory allocations can fail. Rather than failing the > memory hot-add procedure, add a fallback option to allocate vmemmap pages from > discontinuous pages using vmemmap_populate_basepages(). > > Signed-off-by: Sudarshan Rajagopalan > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Anshuman Khandual > Cc: Mark Rutland > Cc: Logan Gunthorpe > Cc: David Hildenbrand > Cc: Andrew Morton > Cc: Steven Price > --- > arch/arm64/mm/mmu.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 75df62f..11f8639 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1121,8 +1121,15 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, > void *p = NULL; > > p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); > - if (!p) > - return -ENOMEM; > + if (!p) { > + /* > + * fallback allocating with virtually > + * contiguous memory for this section > + */ Mapping is always virtually contiguous with or without huge pages. Please drop this comment here, as it's obvious. > + if (vmemmap_populate_basepages(addr, next, node, NULL)) > + return -ENOMEM; Please send in the 'altmap' instead of NULL for allocation from device memory if and when requested. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel