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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 91A8FC433E0 for ; Thu, 4 Mar 2021 00:32:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7175F64EF8 for ; Thu, 4 Mar 2021 00:32:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380616AbhCDAc0 (ORCPT ); Wed, 3 Mar 2021 19:32:26 -0500 Received: from pio-pvt-msa2.bahnhof.se ([79.136.2.41]:56004 "EHLO pio-pvt-msa2.bahnhof.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244083AbhCCTV1 (ORCPT ); Wed, 3 Mar 2021 14:21:27 -0500 Received: from localhost (localhost [127.0.0.1]) by pio-pvt-msa2.bahnhof.se (Postfix) with ESMTP id DE02B3F4D9; Wed, 3 Mar 2021 20:07:56 +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=K3jxx52L; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se 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 WWAsjB0nZGID; Wed, 3 Mar 2021 20:07:55 +0100 (CET) Received: by pio-pvt-msa2.bahnhof.se (Postfix) with ESMTPA id 8A7E93F2DC; Wed, 3 Mar 2021 20:07:53 +0100 (CET) Received: from [192.168.0.209] (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) by mail1.shipmail.org (Postfix) with ESMTPSA id ED2D1360057; Wed, 3 Mar 2021 20:07:52 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1614798473; bh=nKupVD6Xba+2uKQHTUnVnHc3sylFOHvp30xUyrZ7/AU=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=K3jxx52L2803o5MEVtLNblLXmNDqm9f9fB2aegV1Y5Y3ayfcYcOPumRfxAqWSqA4T HLnvLLZzf3rQq74nnomUpdnh2f0sTSKk6VYVaOF5T+Zb26ZifxmuVF/6EOOJrKLj62 dbS6RKPwjMoGEgPlfRiLXT6LrtC/dIbqiBLzZ2Mk= Subject: Re: [Linaro-mm-sig] [PATCH] dma-fence: Document recoverable page fault implications To: Daniel Vetter , DRI Development Cc: Felix Kuehling , Maarten Lankhorst , linaro-mm-sig@lists.linaro.org, Jerome Glisse , =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= , Daniel Vetter , =?UTF-8?Q?Christian_K=c3=b6nig?= , linux-media@vger.kernel.org References: <20210203152921.2429937-1-daniel.vetter@ffwll.ch> From: =?UTF-8?Q?Thomas_Hellstr=c3=b6m_=28Intel=29?= Message-ID: Date: Wed, 3 Mar 2021 20:07:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210203152921.2429937-1-daniel.vetter@ffwll.ch> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On 2/3/21 4:29 PM, Daniel Vetter wrote: > Recently there was a fairly long thread about recoreable hardware page > faults, how they can deadlock, and what to do about that. > > While the discussion is still fresh I figured good time to try and > document the conclusions a bit. This documentation section explains > what's the potential problem, and the remedies we've discussed, > roughly ordered from best to worst. > > v2: Linus -> Linux typoe (Dave) > > v3: > - Make it clear drivers only need to implement one option (Christian) > - Make it clearer that implicit sync is out the window with exclusive > fences (Christian) > - Add the fairly theoretical option of segementing the memory (either > statically or through dynamic checks at runtime for which piece of > memory is managed how) and explain why it's not a great idea (Felix) > > References: https://lore.kernel.org/dri-devel/20210107030127.20393-1-Felix.Kuehling@amd.com/ > Cc: Dave Airlie > Cc: Maarten Lankhorst > Cc: Thomas Hellström > Cc: "Christian König" > Cc: Jerome Glisse > Cc: Felix Kuehling > Signed-off-by: Daniel Vetter > Cc: Sumit Semwal > Cc: linux-media@vger.kernel.org > Cc: linaro-mm-sig@lists.linaro.org > --- > Documentation/driver-api/dma-buf.rst | 76 ++++++++++++++++++++++++++++ > 1 file changed, 76 insertions(+) > Acked-by: Thomas Hellström 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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 679B2C433E0 for ; Wed, 3 Mar 2021 19:08:01 +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 B812364EEE for ; Wed, 3 Mar 2021 19:08:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B812364EEE 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 103336E17A; Wed, 3 Mar 2021 19:08:00 +0000 (UTC) Received: from pio-pvt-msa2.bahnhof.se (pio-pvt-msa2.bahnhof.se [79.136.2.41]) by gabe.freedesktop.org (Postfix) with ESMTPS id 181206E17A for ; Wed, 3 Mar 2021 19:07:59 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by pio-pvt-msa2.bahnhof.se (Postfix) with ESMTP id DE02B3F4D9; Wed, 3 Mar 2021 20:07:56 +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=K3jxx52L; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se 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 WWAsjB0nZGID; Wed, 3 Mar 2021 20:07:55 +0100 (CET) Received: by pio-pvt-msa2.bahnhof.se (Postfix) with ESMTPA id 8A7E93F2DC; Wed, 3 Mar 2021 20:07:53 +0100 (CET) Received: from [192.168.0.209] (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) by mail1.shipmail.org (Postfix) with ESMTPSA id ED2D1360057; Wed, 3 Mar 2021 20:07:52 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1614798473; bh=nKupVD6Xba+2uKQHTUnVnHc3sylFOHvp30xUyrZ7/AU=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=K3jxx52L2803o5MEVtLNblLXmNDqm9f9fB2aegV1Y5Y3ayfcYcOPumRfxAqWSqA4T HLnvLLZzf3rQq74nnomUpdnh2f0sTSKk6VYVaOF5T+Zb26ZifxmuVF/6EOOJrKLj62 dbS6RKPwjMoGEgPlfRiLXT6LrtC/dIbqiBLzZ2Mk= Subject: Re: [Linaro-mm-sig] [PATCH] dma-fence: Document recoverable page fault implications To: Daniel Vetter , DRI Development References: <20210203152921.2429937-1-daniel.vetter@ffwll.ch> From: =?UTF-8?Q?Thomas_Hellstr=c3=b6m_=28Intel=29?= Message-ID: Date: Wed, 3 Mar 2021 20:07:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210203152921.2429937-1-daniel.vetter@ffwll.ch> Content-Language: en-US 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: Felix Kuehling , linaro-mm-sig@lists.linaro.org, Jerome Glisse , =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= , Daniel Vetter , =?UTF-8?Q?Christian_K=c3=b6nig?= , linux-media@vger.kernel.org Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Ck9uIDIvMy8yMSA0OjI5IFBNLCBEYW5pZWwgVmV0dGVyIHdyb3RlOgo+IFJlY2VudGx5IHRoZXJl IHdhcyBhIGZhaXJseSBsb25nIHRocmVhZCBhYm91dCByZWNvcmVhYmxlIGhhcmR3YXJlIHBhZ2UK PiBmYXVsdHMsIGhvdyB0aGV5IGNhbiBkZWFkbG9jaywgYW5kIHdoYXQgdG8gZG8gYWJvdXQgdGhh dC4KPgo+IFdoaWxlIHRoZSBkaXNjdXNzaW9uIGlzIHN0aWxsIGZyZXNoIEkgZmlndXJlZCBnb29k IHRpbWUgdG8gdHJ5IGFuZAo+IGRvY3VtZW50IHRoZSBjb25jbHVzaW9ucyBhIGJpdC4gVGhpcyBk b2N1bWVudGF0aW9uIHNlY3Rpb24gZXhwbGFpbnMKPiB3aGF0J3MgdGhlIHBvdGVudGlhbCBwcm9i bGVtLCBhbmQgdGhlIHJlbWVkaWVzIHdlJ3ZlIGRpc2N1c3NlZCwKPiByb3VnaGx5IG9yZGVyZWQg ZnJvbSBiZXN0IHRvIHdvcnN0Lgo+Cj4gdjI6IExpbnVzIC0+IExpbnV4IHR5cG9lIChEYXZlKQo+ Cj4gdjM6Cj4gLSBNYWtlIGl0IGNsZWFyIGRyaXZlcnMgb25seSBuZWVkIHRvIGltcGxlbWVudCBv bmUgb3B0aW9uIChDaHJpc3RpYW4pCj4gLSBNYWtlIGl0IGNsZWFyZXIgdGhhdCBpbXBsaWNpdCBz eW5jIGlzIG91dCB0aGUgd2luZG93IHdpdGggZXhjbHVzaXZlCj4gICAgZmVuY2VzIChDaHJpc3Rp YW4pCj4gLSBBZGQgdGhlIGZhaXJseSB0aGVvcmV0aWNhbCBvcHRpb24gb2Ygc2VnZW1lbnRpbmcg dGhlIG1lbW9yeSAoZWl0aGVyCj4gICAgc3RhdGljYWxseSBvciB0aHJvdWdoIGR5bmFtaWMgY2hl Y2tzIGF0IHJ1bnRpbWUgZm9yIHdoaWNoIHBpZWNlIG9mCj4gICAgbWVtb3J5IGlzIG1hbmFnZWQg aG93KSBhbmQgZXhwbGFpbiB3aHkgaXQncyBub3QgYSBncmVhdCBpZGVhIChGZWxpeCkKPgo+IFJl ZmVyZW5jZXM6IGh0dHBzOi8vbG9yZS5rZXJuZWwub3JnL2RyaS1kZXZlbC8yMDIxMDEwNzAzMDEy Ny4yMDM5My0xLUZlbGl4Lkt1ZWhsaW5nQGFtZC5jb20vCj4gQ2M6IERhdmUgQWlybGllIDxhaXJs aWVkQGdtYWlsLmNvbT4KPiBDYzogTWFhcnRlbiBMYW5raG9yc3QgPG1hYXJ0ZW4ubGFua2hvcnN0 QGxpbnV4LmludGVsLmNvbT4KPiBDYzogVGhvbWFzIEhlbGxzdHLDtm0gPHRob21hcy5oZWxsc3Ry b21AaW50ZWwuY29tPgo+IENjOiAiQ2hyaXN0aWFuIEvDtm5pZyIgPGNocmlzdGlhbi5rb2VuaWdA YW1kLmNvbT4KPiBDYzogSmVyb21lIEdsaXNzZSA8amdsaXNzZUByZWRoYXQuY29tPgo+IENjOiBG ZWxpeCBLdWVobGluZyA8ZmVsaXgua3VlaGxpbmdAYW1kLmNvbT4KPiBTaWduZWQtb2ZmLWJ5OiBE YW5pZWwgVmV0dGVyIDxkYW5pZWwudmV0dGVyQGludGVsLmNvbT4KPiBDYzogU3VtaXQgU2Vtd2Fs IDxzdW1pdC5zZW13YWxAbGluYXJvLm9yZz4KPiBDYzogbGludXgtbWVkaWFAdmdlci5rZXJuZWwu b3JnCj4gQ2M6IGxpbmFyby1tbS1zaWdAbGlzdHMubGluYXJvLm9yZwo+IC0tLQo+ICAgRG9jdW1l bnRhdGlvbi9kcml2ZXItYXBpL2RtYS1idWYucnN0IHwgNzYgKysrKysrKysrKysrKysrKysrKysr KysrKysrKwo+ICAgMSBmaWxlIGNoYW5nZWQsIDc2IGluc2VydGlvbnMoKykKPgpBY2tlZC1ieTog VGhvbWFzIEhlbGxzdHLDtm0gPHRob21hcy5oZWxsc3Ryb21AbGludXguaW50ZWwuY29tPgoKCl9f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCmRyaS1kZXZlbCBt YWlsaW5nIGxpc3QKZHJpLWRldmVsQGxpc3RzLmZyZWVkZXNrdG9wLm9yZwpodHRwczovL2xpc3Rz LmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2RyaS1kZXZlbAo=