From: Jason Gunthorpe <jgg@mellanox.com>
To: "Yang, Philip" <Philip.Yang@amd.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
Jerome Glisse <jglisse@redhat.com>,
Ralph Campbell <rcampbell@nvidia.com>,
John Hubbard <jhubbard@nvidia.com>,
"Kuehling, Felix" <Felix.Kuehling@amd.com>,
Juergen Gross <jgross@suse.com>,
"Zhou, David(ChunMing)" <David1.Zhou@amd.com>,
Mike Marciniszyn <mike.marciniszyn@intel.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
"nouveau@lists.freedesktop.org" <nouveau@lists.freedesktop.org>,
Dennis Dalessandro <dennis.dalessandro@intel.com>,
"amd-gfx@lists.freedesktop.org" <amd-gfx@lists.freedesktop.org>,
Christoph Hellwig <hch@infradead.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"Deucher, Alexander" <Alexander.Deucher@amd.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Petr Cvek <petrcvekcz@gmail.com>,
"Koenig, Christian" <Christian.Koenig@amd.com>,
Ben Skeggs <bskeggs@redhat.com>
Subject: Re: [PATCH v2 14/15] drm/amdgpu: Use mmu_range_notifier instead of hmm_mirror
Date: Fri, 1 Nov 2019 19:51:28 +0000 [thread overview]
Message-ID: <20191101195124.GU22766@mellanox.com> (raw)
In-Reply-To: <fc6ded68-287b-5257-db79-42c92458a5f6@amd.com>
On Fri, Nov 01, 2019 at 07:45:22PM +0000, Yang, Philip wrote:
> > This must be done inside the notifier_lock, after checking
> > mmu_range_read_retry(), all handling of the struct page must be
> > structured like that.
> >
> Below change will fix this, then driver will call mmu_range_read_retry
> second time using same range->notifier_seq to check if range is
> invalidated inside amdgpu_cs_submit, this looks ok for me.
Lets defer this to some patch trying to fix it, I find it hard to
follow..
> @@ -868,6 +869,13 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo
> *bo, struct page **pages)
> goto out_free_pfns;
> }
>
> + mutex_lock(&adev->notifier_lock);
> +
> + if (mmu_range_read_retry(&bo->notifier, range->notifier_seq)) {
> + mutex_unlock(&adev->notifier_lock);
> + goto retry;
> + }
> +
> for (i = 0; i < ttm->num_pages; i++) {
> pages[i] = hmm_device_entry_to_page(range, range->pfns[i]);
> if (unlikely(!pages[i])) {
> @@ -875,10 +883,12 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo
> *bo, struct page **pages)
> i, range->pfns[i]);
> r = -ENOMEM;
>
> + mutex_unlock(&adev->notifier_lock);
> goto out_free_pfns;
> }
> }
Well, maybe?
The question now is what happens to 'pages' ? With this arrangment the
driver cannot touch 'pages' without also again going under the lock
and checking retry.
If it doesn't touch it, then lets just move this device_entry_to_page
to a more appropriate place?
I'd prefer it if the driver could be structured in the normal way,
with a clear locked region where the page list is handled..
Jason
next prev parent reply other threads:[~2019-11-01 19:52 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-28 20:10 [PATCH v2 00/15] Consolidate the mmu notifier interval_tree and locking Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 01/15] mm/mmu_notifier: define the header pre-processor parts even if disabled Jason Gunthorpe
2019-11-05 21:23 ` John Hubbard
2019-11-06 13:36 ` Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 02/15] mm/mmu_notifier: add an interval tree notifier Jason Gunthorpe
2019-10-29 22:04 ` Kuehling, Felix
2019-10-29 22:56 ` Jason Gunthorpe
2019-11-07 0:23 ` John Hubbard
2019-11-07 2:08 ` Jerome Glisse
2019-11-07 20:11 ` Jason Gunthorpe
2019-11-07 21:04 ` Jerome Glisse
2019-11-08 0:32 ` Jason Gunthorpe
2019-11-08 2:00 ` Jerome Glisse
2019-11-08 20:19 ` Jason Gunthorpe
2019-11-07 20:06 ` Jason Gunthorpe
2019-11-07 20:53 ` John Hubbard
2019-11-08 15:26 ` Jason Gunthorpe
2019-11-08 6:33 ` Christoph Hellwig
2019-11-08 13:43 ` Jerome Glisse
2019-10-28 20:10 ` [PATCH v2 03/15] mm/hmm: allow hmm_range to be used with a mmu_range_notifier or hmm_mirror Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 04/15] mm/hmm: define the pre-processor related parts of hmm.h even if disabled Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 05/15] RDMA/odp: Use mmu_range_notifier_insert() Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 06/15] RDMA/hfi1: Use mmu_range_notifier_inset for user_exp_rcv Jason Gunthorpe
2019-10-29 12:19 ` Dennis Dalessandro
2019-10-29 12:51 ` Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 07/15] drm/radeon: use mmu_range_notifier_insert Jason Gunthorpe
2019-10-29 7:48 ` Koenig, Christian
2019-10-28 20:10 ` [PATCH v2 08/15] xen/gntdev: Use select for DMA_SHARED_BUFFER Jason Gunthorpe
2019-11-01 18:26 ` Jason Gunthorpe
2019-11-05 14:44 ` Jürgen Groß
2019-11-07 9:39 ` Jürgen Groß
2019-10-28 20:10 ` [PATCH v2 09/15] xen/gntdev: use mmu_range_notifier_insert Jason Gunthorpe
2019-10-30 16:55 ` Boris Ostrovsky
2019-11-01 17:48 ` Jason Gunthorpe
2019-11-01 18:51 ` Boris Ostrovsky
2019-11-01 19:17 ` Jason Gunthorpe
2019-11-04 22:03 ` Boris Ostrovsky
2019-11-05 2:31 ` Jason Gunthorpe
2019-11-05 15:16 ` Boris Ostrovsky
2019-11-07 20:36 ` Jason Gunthorpe
2019-11-07 22:54 ` Boris Ostrovsky
2019-11-08 14:53 ` Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 10/15] nouveau: use mmu_notifier directly for invalidate_range_start Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 11/15] nouveau: use mmu_range_notifier instead of hmm_mirror Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 12/15] drm/amdgpu: Call find_vma under mmap_sem Jason Gunthorpe
2019-10-29 7:49 ` Koenig, Christian
2019-10-29 16:28 ` Kuehling, Felix
2019-10-29 13:07 ` Christian König
2019-10-29 17:19 ` Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 13/15] drm/amdgpu: Use mmu_range_insert instead of hmm_mirror Jason Gunthorpe
2019-10-29 7:51 ` Koenig, Christian
2019-10-29 13:59 ` Jason Gunthorpe
2019-10-29 22:14 ` Kuehling, Felix
2019-10-29 23:09 ` Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 14/15] drm/amdgpu: Use mmu_range_notifier " Jason Gunthorpe
2019-10-29 19:22 ` Yang, Philip
2019-10-29 19:25 ` Jason Gunthorpe
2019-11-01 14:44 ` Yang, Philip
2019-11-01 15:12 ` Jason Gunthorpe
2019-11-01 15:59 ` Yang, Philip
2019-11-01 17:42 ` Jason Gunthorpe
2019-11-01 19:19 ` Jason Gunthorpe
2019-11-01 19:45 ` Yang, Philip
2019-11-01 19:50 ` Yang, Philip
2019-11-01 19:51 ` Jason Gunthorpe [this message]
2019-11-01 18:21 ` Jason Gunthorpe
2019-11-01 18:34 ` [PATCH v2a " Jason Gunthorpe
2019-10-28 20:10 ` [PATCH v2 15/15] mm/hmm: remove hmm_mirror and related Jason Gunthorpe
2019-11-01 19:54 ` [PATCH v2 00/15] Consolidate the mmu notifier interval_tree and locking Jason Gunthorpe
2019-11-01 20:54 ` Ralph Campbell
2019-11-04 20:40 ` Jason Gunthorpe
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