From patchwork Fri Jan 24 09:09:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Thomas_Hellstr=C3=B6m_=28Intel=29?= X-Patchwork-Id: 11349929 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F1195924 for ; Fri, 24 Jan 2020 09:09:58 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 CFD332075D for ; Fri, 24 Jan 2020 09:09:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=shipmail.org header.i=@shipmail.org header.b="i5yiCugO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CFD332075D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=shipmail.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9C2806FFAE; Fri, 24 Jan 2020 09:09:54 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from pio-pvt-msa2.bahnhof.se (pio-pvt-msa2.bahnhof.se [79.136.2.41]) by gabe.freedesktop.org (Postfix) with ESMTPS id 66B1B6FFAE for ; Fri, 24 Jan 2020 09:09:53 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by pio-pvt-msa2.bahnhof.se (Postfix) with ESMTP id 7CDD93F684; Fri, 24 Jan 2020 10:09:51 +0100 (CET) Authentication-Results: pio-pvt-msa2.bahnhof.se; dkim=pass (1024-bit key; unprotected) header.d=shipmail.org header.i=@shipmail.org header.b=i5yiCugO; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se X-Spam-Flag: NO X-Spam-Score: -2.099 X-Spam-Level: X-Spam-Status: No, score=-2.099 tagged_above=-999 required=6.31 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no Received: from pio-pvt-msa2.bahnhof.se ([127.0.0.1]) by localhost (pio-pvt-msa2.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id u1YBJXFKoo1R; Fri, 24 Jan 2020 10:09:50 +0100 (CET) Received: from mail1.shipmail.org (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) (Authenticated sender: mb878879) by pio-pvt-msa2.bahnhof.se (Postfix) with ESMTPA id 52E243F516; Fri, 24 Jan 2020 10:09:47 +0100 (CET) Received: from localhost.localdomain.localdomain (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) by mail1.shipmail.org (Postfix) with ESMTPSA id 7EAEA360315; Fri, 24 Jan 2020 10:09:47 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1579856987; bh=0OBWc+qrG3n91MjpvfCc4sv/PlYdJ5/g79jyfk6lzSM=; h=From:To:Cc:Subject:Date:From; b=i5yiCugOnURnUfwxXoml+vC8KrAuHBqALjXrKfBL6xCveEYyjITWuQRxaJYvu8L0A Wb5nmLEGGWH56i98QuEKwVhOJ6LV2Q8q3qaQrI8GoHddItsN8PzYhqHu0PWmXNE+VY 1qGSFFk+ufpSEXCQ09EaEq4+bUZWYTg3hrKYJQQg= From: =?utf-8?q?Thomas_Hellstr=C3=B6m_=28VMware=29?= To: linux-mm@kvack.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 0/9] Huge page-table entries for TTM Date: Fri, 24 Jan 2020 10:09:31 +0100 Message-Id: <20200124090940.26571-1-thomas_os@shipmail.org> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ralph Campbell , Michal Hocko , pv-drivers@vmware.com, =?utf-8?q?Thomas_Hellstr=C3=B6m?= , Dan Williams , "Matthew Wilcox \(Oracle\)" , =?utf-8?b?SsOpcsO0bWUg?= =?utf-8?b?R2xpc3Nl?= , linux-graphics-maintainer@vmware.com, Andrew Morton , =?utf-8?q?Christian_K=C3=B6nig?= , "Kirill A. Shutemov" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" In order to reduce TLB misses and CPU usage this patchset enables huge- and giant page-table entries for TTM and TTM-enabled graphics drivers. Patch 1 and 2 introduce a vma_is_special_huge() function to make the mm code take the same path as DAX when splitting huge- and giant page table entries, (which currently means zapping the page-table entry and rely on re-faulting). Patch 3 makes the mm code split existing huge page-table entries on huge_fault fallbacks. Typically on COW or on buffer-objects that want write-notify. COW and write-notification is always done on the lowest page-table level. See the patch log message for additional considerations. Patch 4 introduces functions to allow the graphics drivers to manipulate the caching- and encryption flags of huge page-table entries without ugly hacks. Patch 5 implements the huge_fault handler in TTM. This enables huge page-table entries, provided that the kernel is configured to support transhuge pages, either by default or using madvise(). However, they are unlikely to be inserted unless the kernel buffer object pfns and user-space addresses align perfectly. There are various options here, but since buffer objects that reside in system pages typically start at huge page boundaries if they are backed by huge pages, we try to enforce buffer object starting pfns and user-space addresses to be huge page-size aligned if their size exceeds a huge page-size. If pud-size transhuge ("giant") pages are enabled by the arch, the same holds for those. Patch 6 implements a specialized huge_fault handler for vmwgfx. The vmwgfx driver may perform dirty-tracking and needs some special code to handle that correctly. Patch 7 implements a drm helper to align user-space addresses according to the above scheme, if possible. Patch 8 implements a TTM range manager for vmwgfx that does the same for graphics IO memory. This may later be reused by other graphics drivers if necessary. Patch 9 finally hooks up the helpers of patch 7 and 8 to the vmwgfx driver. A similar change is needed for graphics drivers that want a reasonable likelyhood of actually using huge page-table entries. If a buffer object size is not huge-page or giant-page aligned, its size will NOT be inflated by this patchset. This means that the buffer object tail will use smaller size page-table entries and thus no memory overhead occurs. Drivers that want to pay the memory overhead price need to implement their own scheme to inflate buffer-object sizes. PMD size huge page-table-entries have been tested with vmwgfx and found to work well both with system memory backed and IO memory backed buffer objects. PUD size giant page-table-entries have seen limited (fault and COW) testing using a modified kernel (to support 1GB page allocations) and a fake vmwgfx TTM memory type. The vmwgfx driver does otherwise not support 1GB-size IO memory resources. Comments and suggestions welcome. Thomas Changes since RFC: * Check for buffer objects present in contigous IO Memory (Christian König) * Rebased on the vmwgfx emulated coherent memory functionality. That rebase adds patch 5. Changes since v1: * Make the new TTM range manager vmwgfx-specific. (Christian König) * Minor fixes for configs that don't support or only partially support transhuge pages. Cc: Andrew Morton Cc: Michal Hocko Cc: "Matthew Wilcox (Oracle)" Cc: "Kirill A. Shutemov" Cc: Ralph Campbell Cc: "Jérôme Glisse" Cc: "Christian König" Cc: Dan Williams