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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: "Thomas Hellström (Intel)" <thomas_os@shipmail.org>,
	"DRI Development" <dri-devel@lists.freedesktop.org>,
	linux-rdma <linux-rdma@vger.kernel.org>,
	"Intel Graphics Development" <intel-gfx@lists.freedesktop.org>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
	"moderated list:DMA BUFFER SHARING FRAMEWORK"
	<linaro-mm-sig@lists.linaro.org>,
	"Thomas Hellstrom" <thomas.hellstrom@intel.com>,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	"open list:DMA BUFFER SHARING FRAMEWORK"
	<linux-media@vger.kernel.org>,
	"Christian König" <christian.koenig@amd.com>,
	"Mika Kuoppala" <mika.kuoppala@intel.com>
Subject: Re: [Linaro-mm-sig] [PATCH 04/18] dma-fence: prime lockdep annotations
Date: Wed, 17 Jun 2020 12:28:35 -0300	[thread overview]
Message-ID: <20200617152835.GF6578@ziepe.ca> (raw)
In-Reply-To: <CAKMK7uE7DKUo9Z+yCpY+mW5gmKet8ugbF3yZNyHGqsJ=e-g_hA@mail.gmail.com>

On Wed, Jun 17, 2020 at 08:48:50AM +0200, Daniel Vetter wrote:

> Now my understanding for rdma is that if you don't have hw page fault
> support,

The RDMA ODP feature is restartable HW page faulting just like nouveau
has. The classical MR feature doesn't have this. Only mlx5 HW supports
ODP today.

> It's only gpus (I think) which are in this awkward in-between spot
> where dynamic memory management really is much wanted, but the hw
> kinda sucks. Aside, about 10+ years ago we had a similar problem with
> gpu hw, but for security: Many gpu didn't have any kinds of page
> tables to isolate different clients from each another. drivers/gpu
> fixed this by parsing&validating what userspace submitted to make sure
> it's only every accessing its own buffers. Most gpus have become
> reasonable nowadays and do have proper per-process pagetables (gpu
> process, not the pasid stuff), but even today there's still some of
> the old model left in some of the smallest SoC.

But I still don't understand why a dma fence is needed inside the GPU
driver itself in the notifier.

Surely the GPU driver can block and release the notifier directly from
its own command processing channel?

Why does this fence and all it entails need to leak out across
drivers?

Jason

  reply	other threads:[~2020-06-17 15:28 UTC|newest]

Thread overview: 99+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-04  8:12 [PATCH 00/18] dma-fence lockdep annotations, round 2 Daniel Vetter
2020-06-04  8:12 ` [PATCH 01/18] mm: Track mmu notifiers in fs_reclaim_acquire/release Daniel Vetter
2020-06-10 12:01   ` Thomas Hellström (Intel)
2020-06-10 12:25     ` [Intel-gfx] " Daniel Vetter
2020-06-10 19:41   ` [PATCH] " Daniel Vetter
2020-06-11 14:29     ` Jason Gunthorpe
2020-06-21 17:42     ` Qian Cai
2020-06-21 18:07       ` Daniel Vetter
2020-06-21 20:01         ` Daniel Vetter
2020-06-21 22:09           ` Qian Cai
2020-06-23 16:17           ` Qian Cai
2020-06-23 22:13             ` Daniel Vetter
2020-06-23 22:29               ` Qian Cai
2020-06-23 22:31       ` Dave Chinner
2020-06-23 22:36         ` Daniel Vetter
2020-06-21 17:00   ` [PATCH 01/18] " Qian Cai
2020-06-21 17:28     ` Daniel Vetter
2020-06-21 17:46       ` Qian Cai
2020-06-04  8:12 ` [PATCH 02/18] dma-buf: minor doc touch-ups Daniel Vetter
2020-06-10 13:07   ` Thomas Hellström (Intel)
2020-06-04  8:12 ` [PATCH 03/18] dma-fence: basic lockdep annotations Daniel Vetter
2020-06-04  8:57   ` Thomas Hellström (Intel)
2020-06-04  9:21     ` Daniel Vetter
     [not found]       ` <159126281827.25109.3992161193069793005@build.alporthouse.com>
2020-06-04  9:36         ` [Intel-gfx] " Daniel Vetter
2020-06-05 13:29   ` [PATCH] " Daniel Vetter
2020-06-05 14:30     ` Thomas Hellström (Intel)
2020-06-11  9:57     ` Maarten Lankhorst
2020-06-10 14:21   ` [Intel-gfx] [PATCH 03/18] " Tvrtko Ursulin
2020-06-10 15:17     ` Daniel Vetter
2020-06-11 10:36       ` Tvrtko Ursulin
2020-06-11 11:29         ` Daniel Vetter
2020-06-11 14:29           ` Tvrtko Ursulin
2020-06-11 15:03             ` Daniel Vetter
     [not found]   ` <159186243606.1506.4437341616828968890@build.alporthouse.com>
2020-06-11  8:44     ` Dave Airlie
2020-06-11  9:01       ` [Intel-gfx] " Daniel Stone
     [not found]         ` <159255511144.7737.12635440776531222029@build.alporthouse.com>
2020-06-19  8:51           ` Daniel Vetter
     [not found]             ` <159255801588.7737.4425728073225310839@build.alporthouse.com>
2020-06-19  9:43               ` Daniel Vetter
     [not found]                 ` <159257233754.7737.17318605310513355800@build.alporthouse.com>
2020-06-22  9:16                   ` Daniel Vetter
2020-07-09  7:29                 ` Daniel Stone
2020-07-09  8:01                   ` Daniel Vetter
2020-06-04  8:12 ` [PATCH 04/18] dma-fence: prime " Daniel Vetter
2020-06-11  7:30   ` [Linaro-mm-sig] " Thomas Hellström (Intel)
2020-06-11  8:34     ` Daniel Vetter
2020-06-11 14:15       ` Jason Gunthorpe
2020-06-11 23:35         ` Felix Kuehling
2020-06-12  5:11           ` Daniel Vetter
2020-06-19 18:13           ` Jerome Glisse
2020-06-23  7:39           ` Daniel Vetter
2020-06-23 18:44             ` Felix Kuehling
2020-06-23 19:02               ` Daniel Vetter
2020-06-16 12:07         ` Daniel Vetter
2020-06-16 14:53           ` Jason Gunthorpe
2020-06-17  7:57             ` Daniel Vetter
2020-06-17 15:29               ` Jason Gunthorpe
2020-06-18 14:42                 ` Daniel Vetter
2020-06-17  6:48           ` Daniel Vetter
2020-06-17 15:28             ` Jason Gunthorpe [this message]
2020-06-18 15:00               ` Daniel Vetter
2020-06-18 17:23                 ` Jason Gunthorpe
2020-06-19  7:22                   ` Daniel Vetter
2020-06-19 11:39                     ` Jason Gunthorpe
2020-06-19 15:06                       ` Daniel Vetter
2020-06-19 15:15                         ` Jason Gunthorpe
2020-06-19 16:19                           ` Daniel Vetter
2020-06-19 17:23                             ` Jason Gunthorpe
2020-06-19 18:09                               ` Jerome Glisse
2020-06-19 18:18                                 ` Jason Gunthorpe
2020-06-19 19:48                                   ` Felix Kuehling
2020-06-19 19:55                                     ` Jason Gunthorpe
2020-06-19 20:03                                       ` Felix Kuehling
2020-06-19 20:31                                       ` Jerome Glisse
2020-06-22 11:46                                         ` Jason Gunthorpe
2020-06-22 20:15                                           ` Jerome Glisse
2020-06-23  0:02                                             ` Jason Gunthorpe
2020-06-19 20:10                                   ` Jerome Glisse
2020-06-19 20:43                                     ` Daniel Vetter
2020-06-19 20:59                                       ` Jerome Glisse
2020-06-23  0:05                                     ` Jason Gunthorpe
2020-06-19 19:11                                 ` Alex Deucher
2020-06-19 19:30                                   ` Felix Kuehling
2020-06-19 19:40                                     ` Jerome Glisse
2020-06-19 19:51                                     ` Jason Gunthorpe
2020-06-04  8:12 ` [PATCH 05/18] drm/vkms: Annotate vblank timer Daniel Vetter
2020-06-04  8:12 ` [PATCH 06/18] drm/vblank: Annotate with dma-fence signalling section Daniel Vetter
2020-06-04  8:12 ` [PATCH 07/18] drm/atomic-helper: Add dma-fence annotations Daniel Vetter
2020-06-04  8:12 ` [PATCH 08/18] drm/amdgpu: add dma-fence annotations to atomic commit path Daniel Vetter
2020-06-23 10:51   ` Daniel Vetter
2020-06-04  8:12 ` [PATCH 09/18] drm/scheduler: use dma-fence annotations in main thread Daniel Vetter
2020-06-04  8:12 ` [PATCH 10/18] drm/amdgpu: use dma-fence annotations in cs_submit() Daniel Vetter
2020-06-04  8:12 ` [PATCH 11/18] drm/amdgpu: s/GFP_KERNEL/GFP_ATOMIC in scheduler code Daniel Vetter
2020-06-04  8:12 ` [PATCH 12/18] drm/amdgpu: DC also loves to allocate stuff where it shouldn't Daniel Vetter
2020-06-04  8:12 ` [PATCH 13/18] drm/amdgpu/dc: Stop dma_resv_lock inversion in commit_tail Daniel Vetter
2020-06-05  8:30   ` Pierre-Eric Pelloux-Prayer
2020-06-05 12:41     ` Daniel Vetter
2020-06-04  8:12 ` [PATCH 14/18] drm/scheduler: use dma-fence annotations in tdr work Daniel Vetter
2020-06-04  8:12 ` [PATCH 15/18] drm/amdgpu: use dma-fence annotations for gpu reset code Daniel Vetter
2020-06-04  8:12 ` [PATCH 16/18] Revert "drm/amdgpu: add fbdev suspend/resume on gpu reset" Daniel Vetter
2020-06-04  8:12 ` [PATCH 17/18] drm/amdgpu: gpu recovery does full modesets Daniel Vetter
2020-06-04  8:12 ` [PATCH 18/18] drm/i915: Annotate dma_fence_work Daniel Vetter

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