Re: [PATCH v16 09/12] mm: enable device page migration from HMM pagewalk

["Mika Penttilä" <mpenttil@redhat.com>]

On 10/21/26 09:19, Balbir Singh wrote:

> On 10/21/26 5:05 PM, mpenttil@redhat.com wrote:
>> From: Mika Penttilä <mpenttil@redhat.com>
>>
>> HMM pagewalk has now the machinery to do the first phase of
>> device page migration, collecting the pfns and installing
>> migration ptes.
>>
>> Enable migration in hmm_range_fault(), and change migrate_vma_setup()
>> to use HMM pagewalk path. Two new flags, MIGRATE_VMA_FAULT and
>> MIGRATE_VMA_WRITE are introduced for migrate_vma_setup(),
>> to request for faulting missing pages, and requesting write
>> access.
>>
>> Also, the migrate_vma_collect*() based paths are now unused,
>> so delete them.
>>
>> Cc: David Hildenbrand <david@kernel.org>
>> Cc: Jason Gunthorpe <jgg@nvidia.com>
>> Cc: Leon Romanovsky <leonro@nvidia.com>
>> Cc: Alistair Popple <apopple@nvidia.com>
>> Cc: Balbir Singh <balbirs@nvidia.com>
>> Cc: Zi Yan <ziy@nvidia.com>
>> Cc: Matthew Brost <matthew.brost@intel.com>
>> Suggested-by: Alistair Popple <apopple@nvidia.com>
>> Signed-off-by: Mika Penttilä <mpenttil@redhat.com>
>> ---
>>  include/linux/migrate.h |  10 +-
>>  mm/hmm.c                |  33 ++-
>>  mm/migrate_device.c     | 562 ++++------------------------------------
>>  3 files changed, 83 insertions(+), 522 deletions(-)
>>
> I got a conflict applying this patch on the latest mm-everything with
> mm: avoid use of VMA_SPECIAL_FLAGS in migrate_vma_setup(), quite a simple fixup
>
> Balbir

Ah okay - yes this is on drm-tip

--Mika