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 A5B3ED149D9 for ; Fri, 25 Oct 2024 17:42:17 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 270D210EB62; Fri, 25 Oct 2024 17:42:17 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=linux.dev header.i=@linux.dev header.b="S8Q80AED"; dkim-atps=neutral Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6469210EB63 for ; Fri, 25 Oct 2024 17:42:15 +0000 (UTC) Message-ID: <712eea49-37f3-4d15-9e04-676937766b65@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1729878133; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3+Jj2781dcd+BwBoELpxEdGuTpRCIY6QYhPS0y3qUZo=; b=S8Q80AEDkavT2o7WucvJJPPV26dWwEjL+JWM+QC4JNItX3+we6/04KXTE97tPiGjRuzxV5 nJGkZ3vZ6bpgpDPWjLcNnzwUNbvNhhXvzZGKvC5YKlAQFsk4NVpJWjA7H6SqmGhrYL9RE8 C9hxNCVjhQLiB+4FBDRW+UbAtJYE9go= Date: Sat, 26 Oct 2024 01:42:06 +0800 MIME-Version: 1.0 Subject: Re: [PATCH 1/3] drm/etnaviv: Track GPU VA size separately To: Lucas Stach , Russell King , Christian Gmeiner Cc: David Airlie , Simona Vetter , etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20241004194207.1013744-1-sui.jingfeng@linux.dev> <20241004194207.1013744-2-sui.jingfeng@linux.dev> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sui Jingfeng In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 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" Hi, On 2024/10/7 18:12, Lucas Stach wrote: > Am Samstag, dem 05.10.2024 um 03:42 +0800 schrieb Sui Jingfeng: >> Etnaviv assumes that GPU page size is 4KiB, yet on some systems, the CPU >> page size is 16KiB. The size of etnaviv buffer objects will be aligned >> to CPU page size on kernel side, however, userspace still assumes the >> page size is 4KiB and doing allocation with 4KiB page as unit. This >> results in userspace allocated GPU virtual address range collision and >> therefore unable to be inserted to the specified hole exactly. >> >> The root cause is that kernel side BO takes up bigger address space than >> userspace assumes when the size of it is not CPU page size aligned. To >> Preserve GPU VA continuous as much as possible, track the size that >> userspace/GPU think of it is. >> >> Yes, we still need to overallocate to suit the CPU, but there is no need >> to waste GPU VA space anymore. >> >> Signed-off-by: Sui Jingfeng >> --- >> drivers/gpu/drm/etnaviv/etnaviv_gem.c | 8 +++++--- >> drivers/gpu/drm/etnaviv/etnaviv_gem.h | 1 + >> drivers/gpu/drm/etnaviv/etnaviv_mmu.c | 8 ++++---- >> 3 files changed, 10 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c >> index 5c0c9d4e3be1..943fc20093e6 100644 >> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c >> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c >> @@ -543,7 +543,7 @@ static const struct drm_gem_object_funcs etnaviv_gem_object_funcs = { >> .vm_ops = &vm_ops, >> }; >> >> -static int etnaviv_gem_new_impl(struct drm_device *dev, u32 flags, >> +static int etnaviv_gem_new_impl(struct drm_device *dev, u32 size, u32 flags, >> const struct etnaviv_gem_ops *ops, struct drm_gem_object **obj) >> { >> struct etnaviv_gem_object *etnaviv_obj; >> @@ -570,6 +570,7 @@ static int etnaviv_gem_new_impl(struct drm_device *dev, u32 flags, >> if (!etnaviv_obj) >> return -ENOMEM; >> >> + etnaviv_obj->user_size = size; >> etnaviv_obj->flags = flags; >> etnaviv_obj->ops = ops; >> >> @@ -588,11 +589,12 @@ int etnaviv_gem_new_handle(struct drm_device *dev, struct drm_file *file, >> { >> struct etnaviv_drm_private *priv = dev->dev_private; >> struct drm_gem_object *obj = NULL; >> + unsigned int user_size = size; > This still needs to be be aligned to 4K. Userspace may request > unaligned buffer sizes and we don't want to risk any confusion about > which part is visible to the GPU, so better make sure this size is > aligned to the GPU page size. OK,aligned to the GPU page size is reasonable. Since the buffer is very high likely be used by GPU. > Also, that more personal preference, but I would call this gpu_size or > something like that, to avoid any confusion with the user_size in > etnaviv_cmdbuf, where user_size doesn't denote the GPU visible size. Yeah, theuser_size denote the length of command buffer, it's usually just need to aligned to 8 bytes. And generally, the size command buffer won't larger than 4KiB (a GPU PAGE). I'm imagine that just 'size' with some extra comment, as it's possible that a buffer is only get used by CPU for specific purpose. Best Regards, Sui > Regards, > Lucas > >> int ret; >> >> size = PAGE_ALIGN(size); >> >> - ret = etnaviv_gem_new_impl(dev, flags, &etnaviv_gem_shmem_ops, &obj); >> + ret = etnaviv_gem_new_impl(dev, user_size, flags, &etnaviv_gem_shmem_ops, &obj); >> if (ret) >> goto fail; >> >> @@ -627,7 +629,7 @@ int etnaviv_gem_new_private(struct drm_device *dev, size_t size, u32 flags, >> struct drm_gem_object *obj; >> int ret; >> >> - ret = etnaviv_gem_new_impl(dev, flags, ops, &obj); >> + ret = etnaviv_gem_new_impl(dev, size, flags, ops, &obj); >> if (ret) >> return ret; >> >> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.h b/drivers/gpu/drm/etnaviv/etnaviv_gem.h >> index a42d260cac2c..c6e27b9abb0c 100644 >> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.h >> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.h >> @@ -36,6 +36,7 @@ struct etnaviv_gem_object { >> const struct etnaviv_gem_ops *ops; >> struct mutex lock; >> >> + u32 user_size; >> u32 flags; >> >> struct list_head gem_node; >> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c >> index 1661d589bf3e..6fbc62772d85 100644 >> --- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c >> +++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c >> @@ -281,6 +281,7 @@ int etnaviv_iommu_map_gem(struct etnaviv_iommu_context *context, >> { >> struct sg_table *sgt = etnaviv_obj->sgt; >> struct drm_mm_node *node; >> + unsigned int user_size; >> int ret; >> >> lockdep_assert_held(&etnaviv_obj->lock); >> @@ -303,13 +304,12 @@ int etnaviv_iommu_map_gem(struct etnaviv_iommu_context *context, >> } >> >> node = &mapping->vram_node; >> + user_size = etnaviv_obj->user_size; >> >> if (va) >> - ret = etnaviv_iommu_insert_exact(context, node, >> - etnaviv_obj->base.size, va); >> + ret = etnaviv_iommu_insert_exact(context, node, user_size, va); >> else >> - ret = etnaviv_iommu_find_iova(context, node, >> - etnaviv_obj->base.size); >> + ret = etnaviv_iommu_find_iova(context, node, user_size); >> if (ret < 0) >> goto unlock; >> -- Best regards, Sui