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=-3.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 D5A03C07E85 for ; Mon, 10 Dec 2018 01:15:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 867952064D for ; Mon, 10 Dec 2018 01:15:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="IGakDlDC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 867952064D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726375AbeLJBPR (ORCPT ); Sun, 9 Dec 2018 20:15:17 -0500 Received: from mail-pl1-f196.google.com ([209.85.214.196]:44057 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726326AbeLJBPR (ORCPT ); Sun, 9 Dec 2018 20:15:17 -0500 Received: by mail-pl1-f196.google.com with SMTP id k8so4404261pls.11 for ; Sun, 09 Dec 2018 17:15:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=MkSsWMVSAeJSTGMkLIBUq4R1LV61HkOQXyu0ciWvNcA=; b=IGakDlDC4jzbyobxgJg+2BtK6pRzujiaHW9b/NlUxa0oN4Q+v0nQbxHrvV6rztYHh8 d3fr24CtYwIkYSO3HiHHaG/leWfyED+lGSqnIV7h/Xbo2OepSP1vmM9e307pfWp5Ne7t 7rnRbEZVNe0rbWbSsRsAUfgBYrhNOmlCsnIq0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=MkSsWMVSAeJSTGMkLIBUq4R1LV61HkOQXyu0ciWvNcA=; b=GacebjeX6lhGgQ3AL5cx7ZqCz/lcl2S4PG1gFzgC9ImsbAIfRJgSSafqUeyF/YE8w/ VjeL6A7OSBvLEUEZT/iQmNoXK4/1aeSwIGx7rENyASuWnhUTn/yDm3LwaoSf3/FH028L /9dvANMQRcDrMYU72ENlGym4mW4hMAqg52ztavPGdrYxfKuITN5b3aaYWNjORTvRI9db Q7/fSS4n768X8dTsWkJzBPLPis8U/Ilq+H8uipwjunghe7RfAftyB6CkBoGCtf7bUslJ AlbLd0Cg6UDgvEHyDDstnFyrmb6i3knWz+1g/WnL607XyNmPy8Czi6fgNYOWnGCppEMW ta/Q== X-Gm-Message-State: AA+aEWaOCvq2x/1i0gjifkxmzn+x2lTv5aHmS3faXayqdA2RigWu6XqB 3HuzcQ2DJ6MI34/nrsqhZq0HTg== X-Google-Smtp-Source: AFSGD/WjUF0Gawkk7vT2zAOu4MoHSXVpXqw+NlA2IDYWtN/771s4IQ/JHyV568QM+ZRV7zANefqpgA== X-Received: by 2002:a17:902:7d90:: with SMTP id a16mr9818780plm.249.1544404516350; Sun, 09 Dec 2018 17:15:16 -0800 (PST) Received: from drinkcat2.tpe.corp.google.com ([2401:fa00:1:b:f659:7f17:ea11:4e8e]) by smtp.gmail.com with ESMTPSA id b10sm16516336pfj.183.2018.12.09.17.15.12 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 09 Dec 2018 17:15:15 -0800 (PST) From: Nicolas Boichat To: Will Deacon Cc: Robin Murphy , Joerg Roedel , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Michal Hocko , Mel Gorman , Levin Alexander , Huaisheng Ye , Mike Rapoport , linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Yong Wu , Matthias Brugger , Tomasz Figa , yingjoe.chen@mediatek.com, hch@infradead.org, Matthew Wilcox , hsinyi@chromium.org, stable@vger.kernel.org Subject: [PATCH v6 0/3] iommu/io-pgtable-arm-v7s: Use DMA32 zone for page tables Date: Mon, 10 Dec 2018 09:15:01 +0800 Message-Id: <20181210011504.122604-1-drinkcat@chromium.org> X-Mailer: git-send-email 2.20.0.rc2.403.gdbc3b29805-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a follow-up to the discussion in [1], [2]. IOMMUs using ARMv7 short-descriptor format require page tables (level 1 and 2) to be allocated within the first 4GB of RAM, even on 64-bit systems. For L1 tables that are bigger than a page, we can just use __get_free_pages with GFP_DMA32 (on arm64 systems only, arm would still use GFP_DMA). For L2 tables that only take 1KB, it would be a waste to allocate a full page, so we considered 3 approaches: 1. This series, adding support for GFP_DMA32 slab caches. 2. genalloc, which requires pre-allocating the maximum number of L2 page tables (4096, so 4MB of memory). 3. page_frag, which is not very memory-efficient as it is unable to reuse freed fragments until the whole page is freed. [3] This series is the most memory-efficient approach. stable@ note: We confirmed that this is a regression, and IOMMU errors happen on 4.19 and linux-next/master on MT8173 (elm, Acer Chromebook R13). The issue most likely starts from commit ad67f5a6545f ("arm64: replace ZONE_DMA with ZONE_DMA32"), i.e. 4.15, and presumably breaks a number of Mediatek platforms (and maybe others?). [1] https://lists.linuxfoundation.org/pipermail/iommu/2018-November/030876.html [2] https://lists.linuxfoundation.org/pipermail/iommu/2018-December/031696.html [3] https://patchwork.codeaurora.org/patch/671639/ Changes since v1: - Add support for SLAB_CACHE_DMA32 in slab and slub (patches 1/2) - iommu/io-pgtable-arm-v7s (patch 3): - Changed approach to use SLAB_CACHE_DMA32 added by the previous commit. - Use DMA or DMA32 depending on the architecture (DMA for arm, DMA32 for arm64). Changes since v2: - Reworded and expanded commit messages - Added cache_dma32 documentation in PATCH 2/3. v3 used the page_frag approach, see [3]. Changes since v4: - Dropped change that removed GFP_DMA32 from GFP_SLAB_BUG_MASK: instead we can just call kmem_cache_*alloc without GFP_DMA32 parameter. This also means that we can drop PATCH v4 1/3, as we do not make any changes in GFP flag verification. - Dropped hunks that added cache_dma32 sysfs file, and moved the hunks to PATCH v5 3/3, so that maintainer can decide whether to pick the change independently. Changes since v5: - Rename ARM_V7S_TABLE_SLAB_CACHE to ARM_V7S_TABLE_SLAB_FLAGS. - Add stable@ to cc. Nicolas Boichat (3): mm: Add support for kmem caches in DMA32 zone iommu/io-pgtable-arm-v7s: Request DMA32 memory, and improve debugging mm: Add /sys/kernel/slab/cache/cache_dma32 Documentation/ABI/testing/sysfs-kernel-slab | 9 +++++++++ drivers/iommu/io-pgtable-arm-v7s.c | 19 +++++++++++++++---- include/linux/slab.h | 2 ++ mm/slab.c | 2 ++ mm/slab.h | 3 ++- mm/slab_common.c | 2 +- mm/slub.c | 16 ++++++++++++++++ tools/vm/slabinfo.c | 7 ++++++- 8 files changed, 53 insertions(+), 7 deletions(-) -- 2.20.0.rc2.403.gdbc3b29805-goog