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 519A33016E4 for ; Thu, 13 Nov 2025 19:15:13 +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=1763061315; cv=none; b=fUyhiLgZRfLvRQjyrfWg5RmYBERzyTBINAQkySiLMfwYzGk/at67dPTsNR5oLaEQzHIyiAz/OSE9ECOP7cV1JEYfscqGOgR03c9JmDsMfC7UPbK3s/MWbS78zK1tetnzKQ6L7MHfASMrRwsek3pmHPr1y7zBmJZdtFV7hWISJLE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763061315; c=relaxed/simple; bh=xTRAYIUWhuhdhUELjp36IphCL7mfl9KtAPUj+d6WIlI=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=AclSDGaP5rptjY+kFpnJt73EtFPs6i9dT/7hBsDAmVTAEC+oejCLlEQBrBUrx9M7dHIatVniutckdl6EINclaNWPBzgkpov88Va6LNDs2JIzi3hBz+03IIQkasnZ1I7N6EWfxiyJ8R8F1vaJ/LHd+kj3KsSf/4n84zaw0FiuZUA= 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=LSFXXFcw; 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="LSFXXFcw" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1763061311; bh=xTRAYIUWhuhdhUELjp36IphCL7mfl9KtAPUj+d6WIlI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=LSFXXFcwKe6wNTcdKO9LZS7m+RPKa7r8YPdQaq5H+xyZ7+JxFNjnfTtXrkzSeReZ3 9k9O02PMcliY4yY4549gL7inVFPkM3YhFi1kyEvkqgMQwHLRGIs+I0/yv64ft+BgQ7 lCwVDxnE3No3qe08m+xWjL3Tm/Ce4CzscbCY4y2vrkYQXL5eYE+p2xhdhwGgHnja/U /PLjp7NaFoLb8v6VQ4ehRgHjimMFsYEHOHn3GuMg7raZYQyTw3YkUCTk0O6IEf7aFB VdJZ8k2lDP0tzMw96zFhtMiW3rGr7FIuf3zqC9KrWUU5B26iLJbFtAEkQC9ZcQtPS7 cyhZ4FXk6yt8A== Received: from fedora (unknown [IPv6:2a01:e0a:2c:6930:d919:a6e:5ea1:8a9f]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by bali.collaboradmins.com (Postfix) with ESMTPSA id C8E4B17E127F; Thu, 13 Nov 2025 20:15:10 +0100 (CET) Date: Thu, 13 Nov 2025 20:15:06 +0100 From: Boris Brezillon To: Akash Goel Cc: liviu.dudau@arm.com, steven.price@arm.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, daniel@ffwll.ch, nd@arm.com Subject: Re: [PATCH] drm/panthor: Avoid adding of kernel BOs to extobj list Message-ID: <20251113201506.76a1af69@fedora> In-Reply-To: <20251113184544.1832461-1-akash.goel@arm.com> References: <20251113184544.1832461-1-akash.goel@arm.com> Organization: Collabora X-Mailer: Claws Mail 4.3.1 (GTK 3.24.51; 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=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 13 Nov 2025 18:45:44 +0000 Akash Goel wrote: > The kernel BOs unnecessarily got added to the external objects list > of drm_gpuvm, when mapping to GPU, which would have resulted in few > extra CPU cycles being spent at the time of job submission as > drm_exec_until_all_locked() loop iterates over all external objects. > > Kernel BOs are private to a VM and so they share the dma_resv object of > the dummy GEM object created for a VM. Use of DRM_EXEC_IGNORE_DUPLICATES > flag ensured the recursive locking of the dummy GEM object was ignored. > Also no extra space got allocated to add fences to the dma_resv object > of dummy GEM object. So no other impact apart from few extra CPU cycles. > > This commit sets the pointer to dma_resv object of GEM object of > kernel BOs before they are mapped to GPU, to prevent them from > being added to external objects list. > > Signed-off-by: Akash Goel With a proper Fixes tag, this is Reviewed-by: Boris Brezillon > --- > drivers/gpu/drm/panthor/panthor_gem.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/panthor/panthor_gem.c > index f369cc3e2a5f..10d255cccc09 100644 > --- a/drivers/gpu/drm/panthor/panthor_gem.c > +++ b/drivers/gpu/drm/panthor/panthor_gem.c > @@ -145,6 +145,9 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm, > bo = to_panthor_bo(&obj->base); > kbo->obj = &obj->base; > bo->flags = bo_flags; > + bo->exclusive_vm_root_gem = panthor_vm_root_gem(vm); > + drm_gem_object_get(bo->exclusive_vm_root_gem); > + bo->base.base.resv = bo->exclusive_vm_root_gem->resv; > > if (vm == panthor_fw_vm(ptdev)) > debug_flags |= PANTHOR_DEBUGFS_GEM_USAGE_FLAG_FW_MAPPED; > @@ -168,9 +171,6 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm, > goto err_free_va; > > kbo->vm = panthor_vm_get(vm); > - bo->exclusive_vm_root_gem = panthor_vm_root_gem(vm); > - drm_gem_object_get(bo->exclusive_vm_root_gem); > - bo->base.base.resv = bo->exclusive_vm_root_gem->resv; > return kbo; > > err_free_va: