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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 D03B9C433E0 for ; Mon, 18 May 2020 15:18:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ABD66207E8 for ; Mon, 18 May 2020 15:18:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=xs4all.nl header.i=@xs4all.nl header.b="MzvkyNhR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728110AbgERPSl (ORCPT ); Mon, 18 May 2020 11:18:41 -0400 Received: from lb3-smtp-cloud9.xs4all.net ([194.109.24.30]:34243 "EHLO lb3-smtp-cloud9.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726918AbgERPSl (ORCPT ); Mon, 18 May 2020 11:18:41 -0400 Received: from cust-b5b5937f ([IPv6:fc0c:c16d:66b8:757f:c639:739b:9d66:799d]) by smtp-cloud9.xs4all.net with ESMTPA id ahXGjvLYt8hmdahXKjhJ8z; Mon, 18 May 2020 17:18:38 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=xs4all.nl; s=s1; t=1589815118; bh=n0fFGCGdi818S+XdCRml9VArGU71ZuuWGQf3y8cVenM=; h=Subject:To:From:Message-ID:Date:MIME-Version:Content-Type:From: Subject; b=MzvkyNhR3+1xg9AJ1h0OcyOrrxCoEWkSUTzgh5VuX3AoGLhjn1B0dqZAeS/cFc6pI kWBr3VTRLnsRgQe6HvGJMYqkkEOkIRE3DhyzxZzpC/m+pufUpCfFPfFGz9Vh1kpVja 1GQg/86BG71p7CkX601+bKjh3esf/3MYj1mWsZjBC8BaMe1Rqlk+2U6lmGdl6zgTIo 8XCv/fYlzAkZdF5jiylQSOtUiTOUq4LYMZb8Mk/R0RSCCbTwE/NKZFtx4sTBQEHCAy /C8zSqiUYTwbwv0e82I3eZTh3s/wVaVN6r86EMtRX+MaVjt2MAVuS5YEO7UyWs41ZM 5Z4cgBEOAmvZg== Subject: Re: [PATCH v6 00/14] Implement V4L2_BUF_FLAG_NO_CACHE_* flags To: Sergey Senozhatsky , Hans Verkuil Cc: Mauro Carvalho Chehab , Tomasz Figa , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200514160153.3646-1-sergey.senozhatsky@gmail.com> From: Hans Verkuil Message-ID: <3fee9a3d-30fe-826a-7a36-b4c9720a94db@xs4all.nl> Date: Mon, 18 May 2020 17:18:34 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200514160153.3646-1-sergey.senozhatsky@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-CMAE-Envelope: MS4wfI6Lht0ujiOXn8w5y/udiDLlkwMRqX60HUf+iJ7HJGUpwLICDz656fqMWX//dHjq1DNJuQh7kF3onp42CadT3ClOKvouGOMf5oKLKuIeja2xByT9mRdh WKXrOGq72IFFDv1SEeMOQs0ZEwqEY7RjYh3senwLjJEjLaYB6WJHezFte8Lb/ns/erZ5w2Dnvt2mc9w8n33seQAbw+D66kWiBDl+cchpqeUsALXPN1GE8ljF PygvybUsvwXN0RFiuA6hX2xoOLhQO6yRN3UgB90to+OYrqOSXciaHs3uEISQ84dR1mNe0egY0JnLygyvaOIQ/Ih8SgjEtr3e5itS7dL8lV1Yi+tQzjYGAuB7 Bk5ZDrl8 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Sergey, On 14/05/2020 18:01, Sergey Senozhatsky wrote: > Hello > > v6 changes: > The design has been slightly reworked. The cache-hints capability has > been renamed to SUPPORTS_MMAP_CACHE_HINTS and is reported for all queues > that support MMAP and allow cache hints. However, the actual hints and > memory consistency are ignored unless the queue is used for the MMAP > streaming I/O. Plus some cleanups, documentation updates, and so on. This looks good. If there are no new comments then I plan to make a PR for 5.9 in two weeks. Thank you for all your work on this! Regards, Hans > > Previous versions: > v5 link: https://lore.kernel.org/lkml/20200424092920.4801-1-sergey.senozhatsky@gmail.com > v4 link: https://lore.kernel.org/lkml/20200302041213.27662-1-senozhatsky@chromium.org/ > v3 link: https://lore.kernel.org/lkml/20200226111529.180197-1-senozhatsky@chromium.org > v2 link: https://lore.kernel.org/lkml/20200204025641.218376-1-senozhatsky@chromium.org/ > v1 link: https://lore.kernel.org/lkml/20191217032034.54897-1-senozhatsky@chromium.org/ > > Series Intro > ======================================================================== > > This is a reworked version of the vb2 cache hints > (V4L2_BUF_FLAG_NO_CACHE_INVALIDATE / V4L2_BUF_FLAG_NO_CACHE_CLEAN) > support patch series which previsouly was developed by Sakari and > Laurent [0]. > > The patch set attempts to preserve the existing behvaiour - cache > sync is performed in ->prepare() and ->finish() (unless the buffer > is DMA exported). User space can request “default behavior” override > with cache management hints, which are handled on a per-buffer basis > and should be supplied with v4l2_buffer ->flags during buffer > preparation. There are two possible hints: > > - V4L2_BUF_FLAG_NO_CACHE_INVALIDATE > No cache sync on ->finish() > > - V4L2_BUF_FLAG_NO_CACHE_CLEAN > No cache sync on ->prepare() > > In order to keep things on the safe side, we also require driver > to explicitly state which of its queues (if any) support user space > cache management hints (such queues should have ->allow_cache_hints > bit set). > > The patch set also (to some extent) simplifies allocators' ->prepare() > and ->finish() callbacks. Namely, we move cache management decision > making to the upper - core - layer. For example, if, previously, we > would have something like this > > vb2_buffer_done() > vb2_dc_finish() > if (buf->db_attach) > return; > > where each allocators' ->finish() callback would either bail > out (DMA exported buffer, for instance) or sync, now that "bail > out or sync" decision is made before we call into the allocator. > > Along with cache management hints, user space is also able to > adjust queue's memory consistency attributes. Memory consistency > attribute (dma_attrs) is per-queue, yet it plays its role on the > allocator level, when we allocate buffers’ private memory (planes). > For the time being, only one consistency attribute is supported: > DMA_ATTR_NON_CONSISTENT. > > [0] https://www.mail-archive.com/linux-media@vger.kernel.org/msg112459.html > > Sergey Senozhatsky (14): > videobuf2: use explicit unsigned int in vb2_queue > videobuf2: add cache management members > videobuf2: handle V4L2 buffer cache flags > videobuf2: add V4L2_FLAG_MEMORY_NON_CONSISTENT flag > videobuf2: add queue memory consistency parameter > videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag > videobuf2: factor out planes prepare/finish functions > videobuf2: do not sync caches when we are allowed not to > videobuf2: check ->synced flag in prepare() and finish() > videobuf2: add begin/end cpu_access callbacks to dma-contig > videobuf2: add begin/end cpu_access callbacks to dma-sg > videobuf2: don't test db_attach in dma-contig prepare and finish > videobuf2: remove redundant if-statement > media: vivid: add cache_hints module param > > Documentation/admin-guide/media/vivid.rst | 9 ++ > .../userspace-api/media/v4l/buffer.rst | 40 +++++- > .../media/v4l/vidioc-create-bufs.rst | 7 +- > .../media/v4l/vidioc-reqbufs.rst | 21 ++- > .../media/common/videobuf2/videobuf2-core.c | 121 +++++++++++++----- > .../common/videobuf2/videobuf2-dma-contig.c | 44 ++++++- > .../media/common/videobuf2/videobuf2-dma-sg.c | 38 ++++-- > .../media/common/videobuf2/videobuf2-v4l2.c | 72 ++++++++++- > drivers/media/dvb-core/dvb_vb2.c | 2 +- > drivers/media/test-drivers/vivid/vivid-core.c | 9 ++ > drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 10 +- > drivers/media/v4l2-core/v4l2-ioctl.c | 5 +- > include/media/videobuf2-core.h | 47 +++++-- > include/uapi/linux/videodev2.h | 14 +- > 14 files changed, 366 insertions(+), 73 deletions(-) >