From: "David Hildenbrand (Arm)" <david@kernel.org>
To: "Yitao Jiang" <jytscientist@hotmail.com>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Christian König" <christian.koenig@amd.com>,
"David Airlie" <airlied@gmail.com>,
"Simona Vetter" <simona@ffwll.ch>,
"Felix Kuehling" <Felix.Kuehling@amd.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Lorenzo Stoakes" <ljs@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
"Liam R . Howlett" <liam@infradead.org>,
Nico Pache <npache@redhat.com>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>, Lance Yang <lance.yang@linux.dev>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Jann Horn <jannh@google.com>,
amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 0/3] mm/mmu_notifier, drm/amdgpu: block THP for GPU user mappings
Date: Thu, 25 Jun 2026 13:47:25 +0200 [thread overview]
Message-ID: <d462612c-508c-4682-a776-92f4f4a40e28@kernel.org> (raw)
In-Reply-To: <SY1PR01MB10596EB75463208A8E1EBBA0FC0EC2@SY1PR01MB10596.ausprd01.prod.outlook.com>
On 6/25/26 12:59, Yitao Jiang wrote:
> Hi,
>
> This series fixes a THP policy problem I found while debugging
> frequent ROCm GPU failures on an AMD Radeon 780M system during ML
> training.
>
> Some AMDGPU/KFD user mappings are registered through interval
> notifiers and cannot safely tolerate the backing VMA changing from base
> pages to a transparent huge page after registration. Userspace can
> still apply MADV_HUGEPAGE or MADV_COLLAPSE, and khugepaged can also
> collapse the range, after the GPU mapping has been registered.
Huh, why? As a memory notifier user, you must be prepared from memory to get
unmapped+remapped at random points in time.
What is the precise problem here? How are you handling THPs at registration time?
Letting arbitrary drivers make THP policies sounds like the very wrong approach.
--
Cheers,
David
next prev parent reply other threads:[~2026-06-25 11:47 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-25 10:59 [PATCH 0/3] mm/mmu_notifier, drm/amdgpu: block THP for GPU user mappings Yitao Jiang
2026-06-25 10:59 ` [PATCH 1/3] mm/mmu_notifier: let interval notifiers block THP Yitao Jiang
2026-06-25 11:50 ` David Hildenbrand (Arm)
2026-06-25 11:58 ` Lorenzo Stoakes
2026-06-25 10:59 ` [PATCH 2/3] drm/amdgpu: block THP for HSA userptr notifiers Yitao Jiang
2026-06-25 12:36 ` Christian König
2026-06-25 10:59 ` [PATCH 3/3] drm/amdkfd: block THP for non-replayable SVM ranges Yitao Jiang
2026-06-25 11:47 ` David Hildenbrand (Arm) [this message]
2026-06-25 11:54 ` [PATCH 0/3] mm/mmu_notifier, drm/amdgpu: block THP for GPU user mappings Lorenzo Stoakes
2026-06-25 12:14 ` 回复: " 蒋 亦韬
2026-06-25 12:35 ` Christian König
2026-06-25 13:01 ` 回复: " 蒋 亦韬
2026-06-25 13:06 ` Christian König
2026-06-25 20:51 ` Kuehling, Felix
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