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=-15.2 required=3.0 tests=BAYES_00, 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=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 DF59EC433B4 for ; Sat, 15 May 2021 18:49:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB4C7611BD for ; Sat, 15 May 2021 18:49:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234507AbhEOSu3 (ORCPT ); Sat, 15 May 2021 14:50:29 -0400 Received: from mx2.suse.de ([195.135.220.15]:58370 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231558AbhEOSu0 (ORCPT ); Sat, 15 May 2021 14:50:26 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 688AAAF5B; Sat, 15 May 2021 18:49:11 +0000 (UTC) Subject: Re: [PATCH v4 1/3] drm: Add support for GEM buffers backed by non-coherent memory To: Paul Cercueil , Maarten Lankhorst , Maxime Ripard , David Airlie , Daniel Vetter Cc: Christoph Hellwig , list@opendingux.net, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org References: <20210515145359.64802-1-paul@crapouillou.net> <20210515145359.64802-2-paul@crapouillou.net> From: Thomas Zimmermann Message-ID: Date: Sat, 15 May 2021 20:49:08 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <20210515145359.64802-2-paul@crapouillou.net> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="sJrRFkDAoEyRy39xoYSrAUozzf6xYe2ID" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --sJrRFkDAoEyRy39xoYSrAUozzf6xYe2ID Content-Type: multipart/mixed; boundary="qhw4perhhhklxwtWZJOyFEtlE03cfno0Q"; protected-headers="v1" From: Thomas Zimmermann To: Paul Cercueil , Maarten Lankhorst , Maxime Ripard , David Airlie , Daniel Vetter Cc: Christoph Hellwig , list@opendingux.net, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org Message-ID: Subject: Re: [PATCH v4 1/3] drm: Add support for GEM buffers backed by non-coherent memory References: <20210515145359.64802-1-paul@crapouillou.net> <20210515145359.64802-2-paul@crapouillou.net> In-Reply-To: <20210515145359.64802-2-paul@crapouillou.net> --qhw4perhhhklxwtWZJOyFEtlE03cfno0Q Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Am 15.05.21 um 16:53 schrieb Paul Cercueil: > Having GEM buffers backed by non-coherent memory is interesting in the > particular case where it is faster to render to a non-coherent buffer > then sync the data cache, than to render to a write-combine buffer, and= > (by extension) much faster than using a shadow buffer. This is true for= > instance on some Ingenic SoCs, where even simple blits (e.g. memcpy) > are about three times faster using this method. >=20 > Add a 'map_noncoherent' flag to the drm_gem_cma_object structure, which= > can be set by the drivers when they create the dumb buffer. >=20 > Since this really only applies to software rendering, disable this flag= > as soon as the CMA objects are exported via PRIME. >=20 > v3: New patch. Now uses a simple 'map_noncoherent' flag to control how > the objects are mapped, and use the new dma_mmap_pages function. >=20 > v4: Make sure map_noncoherent is always disabled when creating GEM > objects meant to be used with dma-buf. >=20 > Signed-off-by: Paul Cercueil Acked-by: Thomas Zimmermann > --- > drivers/gpu/drm/drm_gem_cma_helper.c | 38 +++++++++++++++++++++------= - > include/drm/drm_gem_cma_helper.h | 3 +++ > 2 files changed, 32 insertions(+), 9 deletions(-) >=20 > diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm= _gem_cma_helper.c > index 7942cf05cd93..235c7a63da2b 100644 > --- a/drivers/gpu/drm/drm_gem_cma_helper.c > +++ b/drivers/gpu/drm/drm_gem_cma_helper.c > @@ -46,6 +46,7 @@ static const struct drm_gem_object_funcs drm_gem_cma_= default_funcs =3D { > * __drm_gem_cma_create - Create a GEM CMA object without allocating = memory > * @drm: DRM device > * @size: size of the object to allocate > + * @private: true if used for internal purposes > * > * This function creates and initializes a GEM CMA object of the give= n size, > * but doesn't allocate any memory to back the object. > @@ -55,11 +56,11 @@ static const struct drm_gem_object_funcs drm_gem_cm= a_default_funcs =3D { > * error code on failure. > */ > static struct drm_gem_cma_object * > -__drm_gem_cma_create(struct drm_device *drm, size_t size) > +__drm_gem_cma_create(struct drm_device *drm, size_t size, bool private= ) > { > struct drm_gem_cma_object *cma_obj; > struct drm_gem_object *gem_obj; > - int ret; > + int ret =3D 0; > =20 > if (drm->driver->gem_create_object) > gem_obj =3D drm->driver->gem_create_object(drm, size); > @@ -73,7 +74,14 @@ __drm_gem_cma_create(struct drm_device *drm, size_t = size) > =20 > cma_obj =3D container_of(gem_obj, struct drm_gem_cma_object, base); > =20 > - ret =3D drm_gem_object_init(drm, gem_obj, size); > + if (private) { > + drm_gem_private_object_init(drm, gem_obj, size); > + > + /* Always use writecombine for dma-buf mappings */ > + cma_obj->map_noncoherent =3D false; > + } else { > + ret =3D drm_gem_object_init(drm, gem_obj, size); > + } > if (ret) > goto error; > =20 > @@ -111,12 +119,19 @@ struct drm_gem_cma_object *drm_gem_cma_create(str= uct drm_device *drm, > =20 > size =3D round_up(size, PAGE_SIZE); > =20 > - cma_obj =3D __drm_gem_cma_create(drm, size); > + cma_obj =3D __drm_gem_cma_create(drm, size, false); > if (IS_ERR(cma_obj)) > return cma_obj; > =20 > - cma_obj->vaddr =3D dma_alloc_wc(drm->dev, size, &cma_obj->paddr, > - GFP_KERNEL | __GFP_NOWARN); > + if (cma_obj->map_noncoherent) { > + cma_obj->vaddr =3D dma_alloc_noncoherent(drm->dev, size, > + &cma_obj->paddr, > + DMA_TO_DEVICE, > + GFP_KERNEL | __GFP_NOWARN); > + } else { > + cma_obj->vaddr =3D dma_alloc_wc(drm->dev, size, &cma_obj->paddr, > + GFP_KERNEL | __GFP_NOWARN); > + } > if (!cma_obj->vaddr) { > drm_dbg(drm, "failed to allocate buffer with size %zu\n", > size); > @@ -432,7 +447,7 @@ drm_gem_cma_prime_import_sg_table(struct drm_device=20 *dev, > return ERR_PTR(-EINVAL); > =20 > /* Create a CMA GEM buffer. */ > - cma_obj =3D __drm_gem_cma_create(dev, attach->dmabuf->size); > + cma_obj =3D __drm_gem_cma_create(dev, attach->dmabuf->size, true); > if (IS_ERR(cma_obj)) > return ERR_CAST(cma_obj); > =20 > @@ -499,8 +514,13 @@ int drm_gem_cma_mmap(struct drm_gem_object *obj, s= truct vm_area_struct *vma) > =20 > cma_obj =3D to_drm_gem_cma_obj(obj); > =20 > - ret =3D dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr, > - cma_obj->paddr, vma->vm_end - vma->vm_start); > + vma->vm_page_prot =3D vm_get_page_prot(vma->vm_flags); > + if (!cma_obj->map_noncoherent) > + vma->vm_page_prot =3D pgprot_writecombine(vma->vm_page_prot); > + > + ret =3D dma_mmap_pages(cma_obj->base.dev->dev, > + vma, vma->vm_end - vma->vm_start, > + virt_to_page(cma_obj->vaddr)); > if (ret) > drm_gem_vm_close(vma); > =20 > diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma= _helper.h > index 0a9711caa3e8..cd13508acbc1 100644 > --- a/include/drm/drm_gem_cma_helper.h > +++ b/include/drm/drm_gem_cma_helper.h > @@ -16,6 +16,7 @@ struct drm_mode_create_dumb; > * more than one entry but they are guaranteed to have contiguo= us > * DMA addresses. > * @vaddr: kernel virtual address of the backing memory > + * @map_noncoherent: if true, the GEM object is backed by non-coherent=20 memory > */ > struct drm_gem_cma_object { > struct drm_gem_object base; > @@ -24,6 +25,8 @@ struct drm_gem_cma_object { > =20 > /* For objects with DMA memory allocated by GEM CMA */ > void *vaddr; > + > + bool map_noncoherent; > }; > =20 > #define to_drm_gem_cma_obj(gem_obj) \ >=20 --=20 Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 N=C3=BCrnberg, Germany (HRB 36809, AG N=C3=BCrnberg) Gesch=C3=A4ftsf=C3=BChrer: Felix Imend=C3=B6rffer --qhw4perhhhklxwtWZJOyFEtlE03cfno0Q-- --sJrRFkDAoEyRy39xoYSrAUozzf6xYe2ID Content-Type: application/pgp-signature; name="OpenPGP_signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="OpenPGP_signature" -----BEGIN PGP SIGNATURE----- wsF5BAABCAAjFiEExndm/fpuMUdwYFFolh/E3EQov+AFAmCgF6QFAwAAAAAACgkQlh/E3EQov+A+ EBAAtZY98FyozHDlGm2x7d3eNgL9WTOzVRGUEu9zoZ7uqTT7++ejjpRBsfOB/a+xe8xAkOsIrSkm 0IHmR1uoMAxCfNCT9IYGjGSky/ZAxMWedHxmSZzNfYE4gW5iudZAO5HIBPVFCsmr9EASxSa2Gorz u6t8fBiat9JxNUmGVULgeJogtTfIUX9AYRyMISf2Zs/E1QWVKwsnF5yAI41ePqtdxvj4UNauElnF BRv9JJxg8Sl2jVcvVRaaT9v3KOj/y5nKwxPNaDkfy5unryvUOkW2myws8inkhwPnCJVwt7hz/o69 ub7fJFhX+T9B/3J89+B7lcuERAWcOuYTI7Yz4B05XU9FQTzCvkaKgLBJX3c6eDsYZ5yBEbjSXM1s ozmb7wPrCj2x4SNj+EAPGc65BMWNr60/RBB5E8YQknenHjY1MmcrC0hHUsp258I2Z9SMqGU0ZWy7 XxH+mTIpfFGQ5sQTP4WRq+CSVwH54voG/mQkDLX56oqxfnMKB7Us4ZXKf7Yn/ecyXutvZmzB9q6G r6bnFJPvAaP1LYJuDrD+yBoVCgfT0aKqEwoJxNUAAxFYeBuiTJfsPEd2HS89RxEdup8WTgABlES3 UUhKJ/BwP5XDeL6iUYaajTumKuRi3ncfCp2tvmKTQL3MCKhcG++EHFe6+zu39aZ00Ndp90nqRRPx Ouk= =Mttz -----END PGP SIGNATURE----- --sJrRFkDAoEyRy39xoYSrAUozzf6xYe2ID--