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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A307C433F5 for ; Wed, 22 Dec 2021 21:05:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230063AbhLVVFu (ORCPT ); Wed, 22 Dec 2021 16:05:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229600AbhLVVFt (ORCPT ); Wed, 22 Dec 2021 16:05:49 -0500 Received: from mail-ed1-x533.google.com (mail-ed1-x533.google.com [IPv6:2a00:1450:4864:20::533]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0EBC8C061574 for ; Wed, 22 Dec 2021 13:05:49 -0800 (PST) Received: by mail-ed1-x533.google.com with SMTP id f5so13406162edq.6 for ; Wed, 22 Dec 2021 13:05:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=IQ8ss5cLkN0OPC63IPdBeU3liG7P/Ww64z/LebsIY2w=; b=jOAFEbuBAhj/reb9IQTIUNL+eVriPEapr96s9Pcjc8dBjFsapOITkfRryqtSr8GJqg qW8h7sFiaY16oLLhjNKiIQKkSM/bI1XMZJ04Cie4CYLGobuvnju/nMu6cr7NI0Zmz7rk 4ZK3+roGl3rxTOtfUcZcrgQ5ZAxykXjXUr4dE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=IQ8ss5cLkN0OPC63IPdBeU3liG7P/Ww64z/LebsIY2w=; b=qrbr++ptePc5BgpOeg5xdOJsvc+5HfvSxp3lX/vAG/QGTKt8582+vy4NPMTOygL3io 8xw+HavR3twhBNaGXL3X4VCDmHQhmZpvvYvCW1kB5Cg/J4P3wXT4JhAE8u+14kQ2PPfc 6q1p/O6+E4Ujo3f9pI7LMjJq81gWa/94h7dsneeDzTDhHN0dkjVsSJMD3bjYF/UtuLU3 YSl5IEBEzxqD8406JMXUPgyBafWhTO8e5wrg0c69o6QxmfNSnUnEDhOFulqiU5Si8xjg CeTJA4L7cVl8j0iv0BSN3mmviL2wPkJaCpNjDYronn3fEYBIMwNUlcr4JxKjYACGwSQP PnAg== X-Gm-Message-State: AOAM532DWRwuwfsH7hVDBbWq/2KwqHgaPkJYi2ck21baUFoNG4+3VXiR 0Bli5+x97wqJExVcfJLAgJzN1w== X-Google-Smtp-Source: ABdhPJy16fia4p0Y93NWGi3JF1DLRQj6DXz7tKsGUA5K+83EAZceIlpmfFearrRDhArZk+srL2QzXg== X-Received: by 2002:a05:6402:518c:: with SMTP id q12mr4542433edd.312.1640207147443; Wed, 22 Dec 2021 13:05:47 -0800 (PST) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id o1sm1274867edv.2.2021.12.22.13.05.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Dec 2021 13:05:47 -0800 (PST) Date: Wed, 22 Dec 2021 22:05:45 +0100 From: Daniel Vetter To: Christian =?iso-8859-1?Q?K=F6nig?= Cc: daniel@ffwll.ch, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org Subject: Re: [PATCH 01/24] dma-buf: add dma_resv_replace_fences Message-ID: References: <20211207123411.167006-1-christian.koenig@amd.com> <20211207123411.167006-2-christian.koenig@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20211207123411.167006-2-christian.koenig@amd.com> X-Operating-System: Linux phenom 5.10.0-8-amd64 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Tue, Dec 07, 2021 at 01:33:48PM +0100, Christian König wrote: > This function allows to replace fences from the shared fence list when > we can gurantee that the operation represented by the original fence has > finished or no accesses to the resources protected by the dma_resv > object any more when the new fence finishes. > > Then use this function in the amdkfd code when BOs are unmapped from the > process. > > Signed-off-by: Christian König > --- > drivers/dma-buf/dma-resv.c | 43 ++++++++++++++++ > .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 49 +++---------------- > include/linux/dma-resv.h | 2 + > 3 files changed, 52 insertions(+), 42 deletions(-) > > diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c > index 4deea75c0b9c..a688dbded3d3 100644 > --- a/drivers/dma-buf/dma-resv.c > +++ b/drivers/dma-buf/dma-resv.c > @@ -284,6 +284,49 @@ void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence) > } > EXPORT_SYMBOL(dma_resv_add_shared_fence); > > +/** > + * dma_resv_replace_fences - replace fences in the dma_resv obj > + * @obj: the reservation object > + * @context: the context of the fences to replace > + * @replacement: the new fence to use instead > + * > + * Replace fences with a specified context with a new fence. Only valid if the > + * operation represented by the original fences is completed or has no longer > + * access to the resources protected by the dma_resv object when the new fence > + * completes. > + */ > +void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context, > + struct dma_fence *replacement) > +{ > + struct dma_resv_list *list; > + struct dma_fence *old; > + unsigned int i; > + > + dma_resv_assert_held(obj); > + > + write_seqcount_begin(&obj->seq); > + > + old = dma_resv_excl_fence(obj); > + if (old->context == context) { > + RCU_INIT_POINTER(obj->fence_excl, dma_fence_get(replacement)); > + dma_fence_put(old); > + } > + > + list = dma_resv_shared_list(obj); > + for (i = 0; list && i < list->shared_count; ++i) { > + old = rcu_dereference_protected(list->shared[i], > + dma_resv_held(obj)); > + if (old->context != context) > + continue; > + > + rcu_assign_pointer(list->shared[i], dma_fence_get(replacement)); > + dma_fence_put(old); Since the fences are all guaranteed to be from the same context, maybe we should have a WARN_ON(__dma_fence_is_later()); here just to be safe? With that added: Reviewed-by: Daniel Vetter > + } > + > + write_seqcount_end(&obj->seq); > +} > +EXPORT_SYMBOL(dma_resv_replace_fences); > + > /** > * dma_resv_add_excl_fence - Add an exclusive fence. > * @obj: the reservation object > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c > index 71acd577803e..b558ef0f8c4a 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c > @@ -236,53 +236,18 @@ void amdgpu_amdkfd_release_notify(struct amdgpu_bo *bo) > static int amdgpu_amdkfd_remove_eviction_fence(struct amdgpu_bo *bo, > struct amdgpu_amdkfd_fence *ef) > { > - struct dma_resv *resv = bo->tbo.base.resv; > - struct dma_resv_list *old, *new; > - unsigned int i, j, k; > + struct dma_fence *replacement; > > if (!ef) > return -EINVAL; > > - old = dma_resv_shared_list(resv); > - if (!old) > - return 0; > - > - new = kmalloc(struct_size(new, shared, old->shared_max), GFP_KERNEL); > - if (!new) > - return -ENOMEM; > - > - /* Go through all the shared fences in the resevation object and sort > - * the interesting ones to the end of the list. > + /* TODO: Instead of block before we should use the fence of the page > + * table update and TLB flush here directly. > */ > - for (i = 0, j = old->shared_count, k = 0; i < old->shared_count; ++i) { > - struct dma_fence *f; > - > - f = rcu_dereference_protected(old->shared[i], > - dma_resv_held(resv)); > - > - if (f->context == ef->base.context) > - RCU_INIT_POINTER(new->shared[--j], f); > - else > - RCU_INIT_POINTER(new->shared[k++], f); > - } > - new->shared_max = old->shared_max; > - new->shared_count = k; > - > - /* Install the new fence list, seqcount provides the barriers */ > - write_seqcount_begin(&resv->seq); > - RCU_INIT_POINTER(resv->fence, new); > - write_seqcount_end(&resv->seq); > - > - /* Drop the references to the removed fences or move them to ef_list */ > - for (i = j; i < old->shared_count; ++i) { > - struct dma_fence *f; > - > - f = rcu_dereference_protected(new->shared[i], > - dma_resv_held(resv)); > - dma_fence_put(f); > - } > - kfree_rcu(old, rcu); > - > + replacement = dma_fence_get_stub(); > + dma_resv_replace_fences(bo->tbo.base.resv, ef->base.context, > + replacement); > + dma_fence_put(replacement); > return 0; > } > > diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h > index eebf04325b34..e0be34265eae 100644 > --- a/include/linux/dma-resv.h > +++ b/include/linux/dma-resv.h > @@ -457,6 +457,8 @@ void dma_resv_init(struct dma_resv *obj); > void dma_resv_fini(struct dma_resv *obj); > int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences); > void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence); > +void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context, > + struct dma_fence *fence); > void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence); > int dma_resv_get_fences(struct dma_resv *obj, struct dma_fence **pfence_excl, > unsigned *pshared_count, struct dma_fence ***pshared); > -- > 2.25.1 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch