From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?Q?Christian_K=c3=b6nig?= Subject: Re: dynamic DMA-buf sharing between devices Date: Thu, 18 Apr 2019 12:57:44 +0200 Message-ID: <7cc155fc-1582-9a80-283a-f9e7c84b120d@gmail.com> References: <20190416183841.1577-1-christian.koenig@amd.com> <20190418091315.GU13337@phenom.ffwll.local> Reply-To: christian.koenig-5C7GfCeVMHo@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; Format="flowed" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <20190418091315.GU13337-dv86pmgwkMBes7Z6vYuT8azUEOm+Xw19@public.gmane.org> Content-Language: en-US List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: amd-gfx-bounces-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org Sender: "amd-gfx" To: sumit.semwal-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, linux-media-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linaro-mm-sig-cunTk1MwBs8s++Sfvej+rw@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org QW0gMTguMDQuMTkgdW0gMTE6MTMgc2NocmllYiBEYW5pZWwgVmV0dGVyOgo+IE9uIFR1ZSwgQXBy IDE2LCAyMDE5IGF0IDA4OjM4OjI5UE0gKzAyMDAsIENocmlzdGlhbiBLw7ZuaWcgd3JvdGU6Cj4+ IEhpIGV2ZXJ5Ym9keSwKPj4KPj4gY29yZSBpZGVhIGluIHRoaXMgcGF0Y2ggc2V0IGlzIHRoYXQg RE1BLWJ1ZiBpbXBvcnRlcnMgY2FuIG5vdyBwcm92aWRlIGFuIG9wdGlvbmFsIGludmFsaWRhdGUg Y2FsbGJhY2suIFVzaW5nIHRoaXMgY2FsbGJhY2sgYW5kIHRoZSByZXNlcnZhdGlvbiBvYmplY3Qg ZXhwb3J0ZXJzIGNhbiBub3cgYXZvaWQgcGlubmluZyBETUEtYnVmIG1lbW9yeSBmb3IgYSBsb25n IHRpbWUgd2hpbGUgc2hhcmluZyBpdCBiZXR3ZWVuIGRldmljZXMuCj4+Cj4+IEkndmUgYWxyZWFk eSBzZW5kIG91dCBhbiBvbGRlciB2ZXJzaW9uIHJvdWdobHkgYSB5ZWFyIGFnbywgYnV0IGRpZG4n dCBoYWQgdGltZSB0byBmdXJ0aGVyIGxvb2sgaW50byBjbGVhbmluZyB0aGlzIHVwLgo+Pgo+PiBU aGUgbGFzdCB0aW1lIGEgbWFqb3IgcHJvYmxlbSB3YXMgdGhhdCB3ZSB3b3VsZCBoYWQgdG8gZml4 IHVwIGFsbCBkcml2ZXJzIGltcGxlbWVudGluZyBETUEtYnVmIGF0IG9uY2UuCj4+Cj4+IE5vdyBJ IGF2b2lkIHRoaXMgYnkgYWxsb3dpbmcgbWFwcGluZ3MgdG8gYmUgY2FjaGVkIGluIHRoZSBETUEt YnVmIGF0dGFjaG1lbnQgYW5kIHNvIGRyaXZlciBjYW4gb3B0aW9uYWxseSBtb3ZlIG92ZXIgdG8g dGhlIG5ldyBpbnRlcmZhY2Ugb25lIGJ5IG9uZS4KPj4KPj4gVGhpcyBpcyBhbHNvIGEgcHJlcmVx dWlzaXRlIHRvIG15IHBhdGNoc2V0IGVuYWJsaW5nIHNoYXJpbmcgb2YgZGV2aWNlIG1lbW9yeSB3 aXRoIERNQS1idWYuCj4gT2ssIHdpdGggdGhlIGRpc2N1c3Npb25zIGFuZCB0aGlua2luZyBJIHRo aW5rIHRoaXMgZGVzaWduIGlzIHNvbGlkIGFuZAo+IHNob3VsZCB3b3JrIG91dC4gQnVuY2ggb2Yg YXBpIGFuZCBkb2N1bWVudGF0aW9uIHBvbGlzaGluZyBzdGlsbCB0byBkbywgdG8KPiBtYWtlIHN1 cmUgd2UgaGF2ZSByZWFsbHkgY2xlYXIgc2VtYW50aWNzIGFuZCBhcyBsaXR0bGUgcm9vbSBhcyBw b3NzaWJsZQo+IGZvciBtaXN1bmRlcnN0YW5kaW5nIC0gcmVmYWN0b3JpbmcgYSBtZXNzIGluIGRt YS1idWYgaXMgYSBsb3QgbW9yZSB0cmlja3kKPiB0aGFuIGp1c3QgdHRtLCB0aGVyZSdzIGEgbG90 IG1vcmUgdXNlcnMuCgpZZWFoLCBJJ20gcHJldHR5IGF3YXJlIG9mIHRoYXQgYWZ0ZXIgY2hhbmdp bmcgYWxsIHRoZSB1c2VycyBvZiB0aGUgbWFwIApBUEkgdG8gdXNlIGEgc3RydWN0dXJlIGZvciB0 aGUgcGFyYW1ldGVycy4KCldlbGwgYXQgbGVhc3QgaXQncyBub3QgVUFQSSA6KQoKQ2hyaXN0aWFu Cgo+IC1EYW5pZWwKCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fCmFtZC1nZnggbWFpbGluZyBsaXN0CmFtZC1nZnhAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0 dHBzOi8vbGlzdHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vYW1kLWdmeA== 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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable 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 D857BC10F14 for ; 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([2a02:908:1252:fb60:be8a:bd56:1f94:86e7]) by smtp.gmail.com with ESMTPSA id z63sm1954512wme.30.2019.04.18.03.57.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 18 Apr 2019 03:57:46 -0700 (PDT) Reply-To: christian.koenig@amd.com Subject: Re: dynamic DMA-buf sharing between devices To: sumit.semwal@linaro.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org References: <20190416183841.1577-1-christian.koenig@amd.com> <20190418091315.GU13337@phenom.ffwll.local> From: =?UTF-8?Q?Christian_K=c3=b6nig?= Message-ID: <7cc155fc-1582-9a80-283a-f9e7c84b120d@gmail.com> Date: Thu, 18 Apr 2019 12:57:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190418091315.GU13337@phenom.ffwll.local> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Am 18.04.19 um 11:13 schrieb Daniel Vetter: > On Tue, Apr 16, 2019 at 08:38:29PM +0200, Christian König wrote: >> Hi everybody, >> >> core idea in this patch set is that DMA-buf importers can now provide an optional invalidate callback. Using this callback and the reservation object exporters can now avoid pinning DMA-buf memory for a long time while sharing it between devices. >> >> I've already send out an older version roughly a year ago, but didn't had time to further look into cleaning this up. >> >> The last time a major problem was that we would had to fix up all drivers implementing DMA-buf at once. >> >> Now I avoid this by allowing mappings to be cached in the DMA-buf attachment and so driver can optionally move over to the new interface one by one. >> >> This is also a prerequisite to my patchset enabling sharing of device memory with DMA-buf. > Ok, with the discussions and thinking I think this design is solid and > should work out. Bunch of api and documentation polishing still to do, to > make sure we have really clear semantics and as little room as possible > for misunderstanding - refactoring a mess in dma-buf is a lot more tricky > than just ttm, there's a lot more users. Yeah, I'm pretty aware of that after changing all the users of the map API to use a structure for the parameters. Well at least it's not UAPI :) Christian > -Daniel