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 868A1C77B7A for ; Wed, 17 May 2023 10:19:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EBDFF900005; Wed, 17 May 2023 06:19:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E6D53900003; Wed, 17 May 2023 06:19:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D360E900005; Wed, 17 May 2023 06:19:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id BEB4C900003 for ; Wed, 17 May 2023 06:19:14 -0400 (EDT) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 7DA041404E3 for ; Wed, 17 May 2023 10:19:14 +0000 (UTC) X-FDA: 80799349428.25.12CDCAB Received: from mail-ua1-f48.google.com (mail-ua1-f48.google.com [209.85.222.48]) by imf20.hostedemail.com (Postfix) with ESMTP id A145D1C000F for ; Wed, 17 May 2023 10:19:12 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=linaro.org header.s=google header.b=gx73QOkq; spf=pass (imf20.hostedemail.com: domain of sumit.garg@linaro.org designates 209.85.222.48 as permitted sender) smtp.mailfrom=sumit.garg@linaro.org; dmarc=pass (policy=none) header.from=linaro.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1684318752; 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=OrHrY3AWtq70CRoLtNhxsvgCg243JPmz7/kyzBYJpQA=; b=ShTWTtcBVHkzX4JB+PhvPcwH4EAxkWUxOSZSL5xcWZENAy5j4YcV9cxza5Zs3MwFrY96Qk n7mmNy8FM5dbwm1xDUE84rSmbQcnAEf48GsfsJfHjXhG/cRUJaNN6JGaZMhcPkAjpA9mDp KHq7UoDUye1IFBVCxA/PfAMdcZcgvvE= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=linaro.org header.s=google header.b=gx73QOkq; spf=pass (imf20.hostedemail.com: domain of sumit.garg@linaro.org designates 209.85.222.48 as permitted sender) smtp.mailfrom=sumit.garg@linaro.org; dmarc=pass (policy=none) header.from=linaro.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1684318752; a=rsa-sha256; cv=none; b=Iqb1VfSh+aAZL8cqbWCkYbjguaMjhW6MKsUtOednMgdC63fglRIdU3hpASMyTmpassiM0r 00QlGzfu1IpPPyIvFb5l70ztzwPej0/sJZxJuKrA1OIABDJTPoHPcG0NgrKN00QmSe+zYy 6yiEehg/Atzqs0tSFXrkiTe3yPfXOjU= Received: by mail-ua1-f48.google.com with SMTP id a1e0cc1a2514c-783f17f0a00so216912241.2 for ; Wed, 17 May 2023 03:19:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1684318751; x=1686910751; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=OrHrY3AWtq70CRoLtNhxsvgCg243JPmz7/kyzBYJpQA=; b=gx73QOkq3byJIA/Bb/mmsN9l7Oz6EDJzEum6sbZ3Du/ESMpCrjyioyH0N9FWcwijXM +NyJZyziL7HGeGgIkhmTVFF0Qxb40NcFuFoneKGdSAjo/1DnKBfOyuTM4rRaYqLJGq7c QIWiNpi/sxFZ5zHKF245m3qOEb4GeX48lYZ0jZ3ToNt2qfbLERFcdBQpsOuXB971LJJ7 gl2zBEpZdKtjmNHs5ZJTLJdlRa86JMIdfwyOCHNDFpkxpKv9op0twjBO9rBNxlovc578 foz1HwAK7hRLdoQVMoQIhAwfd/88fHF1+KlE0VSxD4KtH6Mjwt29JraZjX23m7C0xtsb xSwA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684318751; x=1686910751; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=OrHrY3AWtq70CRoLtNhxsvgCg243JPmz7/kyzBYJpQA=; b=QDMvuBUWCnmTz9AOr3Z19dAzzy0OGiI5+CyghhpQofDpqgdKR085vTYP4ufuKVyhbz ONJQHFGS48YQkrmqQb58BQA1kVhWh2NWdgfzFWvN6FyzUVQj19efQBfSv79yG3be5Lc/ cL277gkXt8DntrGRKNIYlWe3lxPDrz/PcIpYg9pog4ZNh+PdddGKMRDoKlA1iUzHhEqY z8VOHX+RtuE7btob+xRzuH5c7XiUcH3BcB2pZCp/QNPtB+jt7Ta2wfgqR/UnSWqin2wx DGWCvG75sZcYdsTYa9hkl2Ipm12UeJUAsDY+tStXleZai9KnMMSDl8CDtGMXRWT3DVMg 7bMg== X-Gm-Message-State: AC+VfDzPOTdLXXmKXjbnfGojGWfqYpRk1f9YklekNgaV4ru/MgHL/UDg HY6p6rToeAvei1mtgE4Bh01TPy43vBS4kX6VU27cmg== X-Google-Smtp-Source: ACHHUZ5Mb/NeiO/iDJb+RFsGn+oHgCv/thgz5utXRC5vjJkVkqjaX/1mVMnKg6tlXR15pAZMUKKT+mZqUv4DrifFGrs= X-Received: by 2002:a67:f94b:0:b0:436:5a8b:14e0 with SMTP id u11-20020a67f94b000000b004365a8b14e0mr4386138vsq.26.1684318751690; Wed, 17 May 2023 03:19:11 -0700 (PDT) MIME-Version: 1.0 References: <20230517031856.19660-1-xiaoming.ding@mediatek.com> In-Reply-To: From: Sumit Garg Date: Wed, 17 May 2023 15:49:00 +0530 Message-ID: Subject: Re: [PATCH] tee: add FOLL_LONGTERM for CMA case when alloc shm To: Christoph Hellwig , Xiaoming Ding Cc: Jens Wiklander , Matthias Brugger , AngeloGioacchino Del Regno , op-tee@lists.trustedfirmware.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, fei.xu@mediatek.com, srv_heupstream@mediatek.com, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: A145D1C000F X-Stat-Signature: gbeywoeqmj9qky1peasuasoqxy186wo4 X-HE-Tag: 1684318752-717359 X-HE-Meta: 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 4r8vTV1T Y5EmzvfT2A3TiyDUnlFLPR5Felsy53oIcf6Aubd4JkbecmskY6rSRjJ19k2sYiMPpK4YHgaH5UN7tQwe6+UCz528UbBsjyxmdRJm8mhlScIV7/UmG7A50/8/CEBRA4O/1oiLV9F8KHABhRycWg+2nvg1PCU6PouFw97FOav8tjkZ1PPkQoa1/mR9c5qV7JvM66q03ey8fmm6rCWEwSDBAsUAc7pg960uY8KEdFNztN//oQDkNTyglabVATDGSMPXjlJGp1WHO9SKxEi7bIfFK5IRfOjXYRdWCZaRRKEqGbtsSMsZRAD18jBCOrSKdgVs++YfbtB1pWfO9t+NRPzn2GVNhFVjplxVaJR9AWS+zJDCezMI0OiVLIjRowVrTDBpgsMiUXTGRk+8fQKpKzoczYbAcFg== 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: On Wed, 17 May 2023 at 15:06, Christoph Hellwig wrote: > > On Wed, May 17, 2023 at 02:56:13PM +0530, Sumit Garg wrote: > > Do you mean a pinned user-space page can be paged out automatically? > > No, pinned pages can't be paged out. > > But a short term pin implies it will be release after a short delay, > and it is feasible for wait for the pin to go away. Okay, I see. I would be interested to know the ranges for that short delay. I guess it may depend on how much memory pressure there is... > > For a long term pin waiting is not an option, and anyone wanting to > do something with the pinned page that requires it to not be pinned > must simply give up. > > > Just FYI, the underlying use-case for TEE registered shared memory is > > that the references to pinned pages are provided to TEE implementation > > to operate upon. This can happen over multiple syscalls and we want > > the pinned pages to be always in RAM as otherwise the physical > > addresses may change if they are paged out in between. > > That's a very use clear case for a long term pin. ...however, thanks for the insights. @Xiaoming, Please use the following fixes tag for the v2 along with extending the commit description regarding the reliability provided by the long term flag. Fixes: 033ddf12bcf5 ("tee: add register user memory") -Sumit