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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 515D5C282EC for ; Mon, 10 Mar 2025 16:28:33 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 18190280005; Mon, 10 Mar 2025 12:28:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 131F0280004; Mon, 10 Mar 2025 12:28:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F3B78280005; Mon, 10 Mar 2025 12:28:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id D556E280004 for ; Mon, 10 Mar 2025 12:28:31 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 1131D141293 for ; Mon, 10 Mar 2025 16:28:32 +0000 (UTC) X-FDA: 83206174464.13.48D87C0 Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf23.hostedemail.com (Postfix) with ESMTP id 77B3A140012 for ; Mon, 10 Mar 2025 16:28:30 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=HjCRfgvh; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf23.hostedemail.com: domain of mripard@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=mripard@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1741624110; a=rsa-sha256; cv=none; b=hZfueal8ckw2z1TkQv+wjPTGpwRIu0pbAxfg00EA/se0lf2UU0tbr7skFHgnyQqy54K9+Q QhaC6ord31slsMYkflwW2C55nRGnjVnxVwHO0YfLKV2BB86Dsn9Lbp4ote+Jl7HkNbZSr5 rTQ2A3AxP2GF+g81/Ew34mmdHXsO/XE= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=HjCRfgvh; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf23.hostedemail.com: domain of mripard@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=mripard@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1741624110; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=sfvhajnKh+JsG0G6ZCvurp8nXoOWJhhwIboB81/bSrw=; b=WfmMZ1+B6ZdcC3FE8krLSuzzlhvgP2z5qvPkH61KCQvM13iTBS1xGYdaCF/fbfK/Kg9Fzc hCJMk7aiNny6Ubq5um7Les69HqgBIGLkIlGSGkJ/EXV6j5WDiqaoaE4NLdGzrvRo7G9mMX w0BwwqUf/QyzqElXVKM8C5lR5yJiLJ0= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 80D8BA45A5A; Mon, 10 Mar 2025 16:22:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3E28C4CEE5; Mon, 10 Mar 2025 16:28:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741624109; bh=sfvhajnKh+JsG0G6ZCvurp8nXoOWJhhwIboB81/bSrw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HjCRfgvhI4AlUc9WjlFhsPXUiJyzrUc7p1qSry8OFL6MdHrIU9dymbeJiT9YIoP0D VpC7Nku3EXjciL5/o5SgIqVML56l8wAsBs9D0MV02GYwaxyVQleOU1pZm20IaC9MqS 6WL2AQtsDOrq/PSSrVIqLEmgiG7O2qg68NrFKbo0o/GbNDo1vAl8GfYDxMYrV6IemA TA2xBT4nqJ+pqLZuSkQGtcP74qh8qiWlsFnT1nJd8PimtWtBMONmIe6Y1t9kfiJZfa zgaHp90KP/TRdKxL6fw5PTlDtElMmsEjwJkxJo+mqgxXI69OPILcXnnV23cR/5WNFt Lra5gXAYY48XQ== Date: Mon, 10 Mar 2025 17:28:26 +0100 From: Maxime Ripard To: Robin Murphy Cc: Andrew Morton , Marek Szyprowski , Sumit Semwal , Christian =?utf-8?B?S8O2bmln?= , Benjamin Gaignard , Brian Starkey , John Stultz , "T.J. Mercier" , Maarten Lankhorst , Thomas Zimmermann , David Airlie , Simona Vetter , Tomasz Figa , Mauro Carvalho Chehab , Hans Verkuil , Laurent Pinchart , linux-mm@kvack.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org Subject: Re: [PATCH RFC 06/12] dma: direct: Provide accessor to dmem region Message-ID: <20250310-expert-piculet-of-fascination-3813cd@houat> References: <20250310-dmem-cgroups-v1-0-2984c1bc9312@kernel.org> <20250310-dmem-cgroups-v1-6-2984c1bc9312@kernel.org> <2af9ea85-b31d-49c9-b574-38c33cc89cef@arm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="u3dzblkp3nldqa3e" Content-Disposition: inline In-Reply-To: <2af9ea85-b31d-49c9-b574-38c33cc89cef@arm.com> X-Rspamd-Queue-Id: 77B3A140012 X-Stat-Signature: if6s5ucuut475tkydfexhr77uqf798ue X-Rspamd-Server: rspam02 X-Rspam-User: X-HE-Tag: 1741624110-469546 X-HE-Meta: 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 39yjPz5d yiEF8oeD+nWw0NUCVq9/P8qCGUMi7seUs8FmWk1FaLZsZXeV0sNFq0/Col80cu0DUSxiE+2c4/OOFu0ZVUre6m9NfpVhwc5xFHvSQWeAjPsg/6lCS/reI+Gh/Rn+s4gQypNjVI3dulp6L1hukCk+7HJFh/jWXW9HlNxpxsPpOC41o0wDzCvYggRX3Auyi+kK6XB3oHNFoS4mQTOP/O61fB2SG6j7qpQWxys2yzNo8xQOrMknSg/EhZSf6MCoOY5VXgwor76WqsmrfI6R9IKai9cJKfeEkggg0wp/0G9BEaY4wBLuRRSye+kS6Ok43h6WMIYnw/b16+ixgPwwpFXidiv8pUalNTAeEqS9YrXoLzgSVtP0tomdHVoqWB3LF1nebj48xYNb9EJN0R7zx8vXEbBoAaZaX3FaQpquHIq8+IywFEQWpvvJXkShR+g== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: --u3dzblkp3nldqa3e Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH RFC 06/12] dma: direct: Provide accessor to dmem region MIME-Version: 1.0 On Mon, Mar 10, 2025 at 02:56:37PM +0000, Robin Murphy wrote: > On 2025-03-10 12:06 pm, Maxime Ripard wrote: > > Consumers of the direct DMA API will have to know which region their > > device allocate from in order for them to charge the memory allocation > > in the right one. >=20 > This doesn't seem to make much sense - dma-direct is not an allocator > itself, it just provides the high-level dma_alloc_attrs/dma_alloc_pages/e= tc. > interfaces wherein the underlying allocations _could_ come from CMA, but > also a per-device coherent/restricted pool, or a global coherent/atomic > pool, or the regular page allocator, or in one weird corner case the SWIO= TLB > buffer, or... I guess it wasn't super clear, but what I meant is that it's an allocator to the consumer: it gets called, and returns a buffer. How it does so is transparent to the device, and on the other side of the abstraction. I do agree that the logic is complicated to follow, and that's what I was getting at in the cover letter. Maxime --u3dzblkp3nldqa3e Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCZ88TKQAKCRDj7w1vZxhR xeXsAP4+bkSf79vghGDX51PPSs2osfbQ4iJhpf10VBrMEcmucQD/fkdqnL4MMQHy pTxcWVuD9g8C9rHEtoXUgWXksoghYQ4= =f/EX -----END PGP SIGNATURE----- --u3dzblkp3nldqa3e--