From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0B7AB26BD90 for ; Tue, 25 Feb 2025 15:05:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.251.105.195 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740495909; cv=none; b=rRx+3W17FUJbTpmsmrAKyEge41KYkF9ii9scQzFcNG+SjoU110MXyFL6w81FFemPN4EZc81V5nBvoP9cyT+QUMgc+yieD9s63bjodPAgWIQ6K3vr/p7wTgoYhEOmoIEuiXbqrsxqvFxka5z/IEJArC3kyhvC3L52Q8r7tT9/mJQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740495909; c=relaxed/simple; bh=xCTtrHDdXUTIma0E6i1UNMQGYB9gWHwdyQbD5ikxQig=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=i5UBf8Um1fr7ic4IEKKOFrGkYl9zNE8x5tU2ym3XxJ0C3Hc5xfms2PQ2MRjKhWdqpMqVg4Bq12E0tUuRY55+4d+Xe6hFKAS1mXrDBktcHThFIEHQrs9tDCXzxo0yQTPukmP0Z2aqFmUO/nOBnVld7lKEzbp/+4JH4g9gdoycUqM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=MLWQZpXz; arc=none smtp.client-ip=148.251.105.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="MLWQZpXz" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1740495905; bh=xCTtrHDdXUTIma0E6i1UNMQGYB9gWHwdyQbD5ikxQig=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=MLWQZpXzxGEwiizt3jBSXSieYKq5MHfftP6Zw4kzkzUVZ6eyd+EhyCwqgrrWqKnt7 mFhuEpstRuKMWuY+ONICCuMs6jxVOefolMEMx5fOWERsqa33NhtVvhDv70yl289oP6 QD/r/0Al8nXN/t34OV6fYGmiWrNsv0jvWyplMxHH6Rj7Mth47iRccC2Plk0YxNcWoC Sb43qL4SUXJBtWDfBwra2nSbj9AzwcDhlED0Vs4poJMHQNRryp3taSnw7qgZUGqv5k sRN3og3MfutSmqt5eUrelyAn8fTtH15NvKNbyskHebDYD083sC0+boRJRBaEdwVnSR P0h26cIWx6I2A== Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by bali.collaboradmins.com (Postfix) with ESMTPSA id 9FB5217E0CFA; Tue, 25 Feb 2025 16:05:04 +0100 (CET) Date: Tue, 25 Feb 2025 16:04:59 +0100 From: Boris Brezillon To: =?UTF-8?B?QWRyacOhbg==?= Larumbe Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Steven Price , Rob Herring , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , kernel@collabora.com Subject: Re: [RFC PATCH 6/7] drm/panfrost: Use shmem sparse allocation for heap BOs Message-ID: <20250225160459.664ce342@collabora.com> In-Reply-To: <20250218232552.3450939-7-adrian.larumbe@collabora.com> References: <20250218232552.3450939-1-adrian.larumbe@collabora.com> <20250218232552.3450939-7-adrian.larumbe@collabora.com> Organization: Collabora X-Mailer: Claws Mail 4.3.0 (GTK 3.24.43; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Tue, 18 Feb 2025 23:25:36 +0000 Adri=C3=A1n Larumbe wrote: > Panfrost heap BOs grow on demand when the GPU triggers a page fault after > accessing an address within the BO's virtual range. >=20 > We still store the sgts we get back from the shmem sparse allocation func= tion, > since it was decided management of sparse memory SGTs should be done by c= lient > drivers rather than the shmem subsystem. >=20 > Signed-off-by: Adri=C3=A1n Larumbe > --- > drivers/gpu/drm/panfrost/panfrost_gem.c | 12 ++-- > drivers/gpu/drm/panfrost/panfrost_gem.h | 2 +- > drivers/gpu/drm/panfrost/panfrost_mmu.c | 85 +++++-------------------- > 3 files changed, 25 insertions(+), 74 deletions(-) >=20 > diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/pa= nfrost/panfrost_gem.c > index 8e0ff3efede7..0cda2c4e524f 100644 > --- a/drivers/gpu/drm/panfrost/panfrost_gem.c > +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c > @@ -40,10 +40,10 @@ static void panfrost_gem_free_object(struct drm_gem_o= bject *obj) > int n_sgt =3D bo->base.base.size / SZ_2M; > =20 > for (i =3D 0; i < n_sgt; i++) { > - if (bo->sgts[i].sgl) { > - dma_unmap_sgtable(pfdev->dev, &bo->sgts[i], > + if (bo->sgts[i]) { > + dma_unmap_sgtable(pfdev->dev, bo->sgts[i], > DMA_BIDIRECTIONAL, 0); > - sg_free_table(&bo->sgts[i]); > + sg_free_table(bo->sgts[i]); > } > } > kvfree(bo->sgts); > @@ -274,7 +274,11 @@ panfrost_gem_create(struct drm_device *dev, size_t s= ize, u32 flags) > if (flags & PANFROST_BO_HEAP) > size =3D roundup(size, SZ_2M); > =20 > - shmem =3D drm_gem_shmem_create(dev, size); > + if (flags & PANFROST_BO_HEAP) > + shmem =3D drm_gem_shmem_create_sparse(dev, size); > + else > + shmem =3D drm_gem_shmem_create(dev, size); > + > if (IS_ERR(shmem)) > return ERR_CAST(shmem); > =20 > diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/pa= nfrost/panfrost_gem.h > index 7516b7ecf7fe..2a8d0752011e 100644 > --- a/drivers/gpu/drm/panfrost/panfrost_gem.h > +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h > @@ -11,7 +11,7 @@ struct panfrost_mmu; > =20 > struct panfrost_gem_object { > struct drm_gem_shmem_object base; > - struct sg_table *sgts; > + struct sg_table **sgts; I guess using an xarray here would make sense. Or maybe even an sg_append_table, since we don't expect holes in the populated pages. This makes me wonder if we really want the gem_shmem layer to automate sgt creation for sparse GEM objects. Looks like something the driver can easily optimize for its use-case.