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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 87B02CD98D2 for ; Thu, 13 Nov 2025 19:15:14 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id EBAE110E924; Thu, 13 Nov 2025 19:15:13 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="LSFXXFcw"; dkim-atps=neutral Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1656E10E924 for ; Thu, 13 Nov 2025 19:15:13 +0000 (UTC) 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) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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: