drivers/gpu/drm/nouveau/nouveau_dmem.c | 246 +++++--- drivers/gpu/drm/nouveau/nouveau_svm.c | 6 +- drivers/gpu/drm/nouveau/nouveau_svm.h | 3 +- include/linux/huge_mm.h | 18 +- include/linux/memremap.h | 29 +- include/linux/migrate.h | 2 + include/linux/mm.h | 1 + lib/test_hmm.c | 428 ++++++++++--- lib/test_hmm_uapi.h | 3 + mm/huge_memory.c | 261 ++++++-- mm/memory.c | 6 +- mm/memremap.c | 50 +- mm/migrate.c | 2 + mm/migrate_device.c | 488 ++++++++++++--- mm/page_alloc.c | 1 + mm/page_vma_mapped.c | 10 + mm/pgtable-generic.c | 6 + mm/rmap.c | 19 +- tools/testing/selftests/mm/hmm-tests.c | 805 ++++++++++++++++++++++++- 19 files changed, 2072 insertions(+), 312 deletions(-)
This patch series adds support for THP migration of zone device pages. To do so, the patches implement support for folio zone device pages by adding support for setting up larger order pages. These patches build on the earlier posts by Ralph Campbell [1] Two new flags are added in vma_migration to select and mark compound pages. migrate_vma_setup(), migrate_vma_pages() and migrate_vma_finalize() support migration of these pages when MIGRATE_VMA_SELECT_COMPOUND is passed in as arguments. The series also adds zone device awareness to (m)THP pages along with fault handling of large zone device private pages. page vma walk and the rmap code is also zone device aware. Support has also been added for folios that might need to be split in the middle of migration (when the src and dst do not agree on MIGRATE_PFN_COMPOUND), that occurs when src side of the migration can migrate large pages, but the destination has not been able to allocate large pages. The code supported and used folio_split() when migrating THP pages, this is used when MIGRATE_VMA_SELECT_COMPOUND is not passed as an argument to migrate_vma_setup(). The test infrastructure lib/test_hmm.c has been enhanced to support THP migration. A new ioctl to emulate failure of large page allocations has been added to test the folio split code path. hmm-tests.c has new test cases for huge page migration and to test the folio split path. A new throughput test has been added as well. The nouveau dmem code has been enhanced to use the new THP migration capability. Feedback from the RFC [2]: It was advised that prep_compound_page() not be exposed just for the purposes of testing (test driver lib/test_hmm.c). Work arounds of copy and split the folios did not work due to lock order dependency in the callback for split folio. mTHP support: The patches hard code, HPAGE_PMD_NR in a few places, but the code has been kept generic to support various order sizes. With additional refactoring of the code support of different order sizes should be possible. The future plan is to post enhancements to support mTHP with a rough design as follows: 1. Add the notion of allowable thp orders to the HMM based test driver 2. For non PMD based THP paths in migrate_device.c, check to see if a suitable order is found and supported by the driver 3. Iterate across orders to check the highest supported order for migration 4. Migrate and finalize The mTHP patches can be built on top of this series, the key design elements that need to be worked out are infrastructure and driver support for multiple ordered pages and their migration. References: [1] https://lore.kernel.org/linux-mm/20201106005147.20113-1-rcampbell@nvidia.com/ [2] https://lore.kernel.org/linux-mm/20250306044239.3874247-3-balbirs@nvidia.com/T/ These patches are built on top of mm-unstable Cc: Karol Herbst <kherbst@redhat.com> Cc: Lyude Paul <lyude@redhat.com> Cc: Danilo Krummrich <dakr@kernel.org> Cc: David Airlie <airlied@gmail.com> Cc: Simona Vetter <simona@ffwll.ch> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Shuah Khan <shuah@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Donet Tom <donettom@linux.ibm.com> Changelog v1: - Changes from RFC [2], include support for handling fault_folio and using trylock in the fault path - A new test case has been added to measure the throughput improvement - General refactoring of code to keep up with the changes in mm - New split folio callback when the entire split is complete/done. The callback is used to know when the head order needs to be reset. Testing: - Testing was done with ZONE_DEVICE private pages on an x86 VM - Throughput showed upto 5x improvement with THP migration, system to device migration is slower due to the mirroring of data (see buffer->mirror) Balbir Singh (12): mm/zone_device: support large zone device private folios mm/migrate_device: flags for selecting device private THP pages mm/thp: zone_device awareness in THP handling code mm/migrate_device: THP migration of zone device pages mm/memory/fault: Add support for zone device THP fault handling lib/test_hmm: test cases and support for zone device private THP mm/memremap: Add folio_split support mm/thp: add split during migration support lib/test_hmm: add test case for split pages selftests/mm/hmm-tests: new tests for zone device THP migration gpu/drm/nouveau: Add THP migration support selftests/mm/hmm-tests: New throughput tests including THP drivers/gpu/drm/nouveau/nouveau_dmem.c | 246 +++++--- drivers/gpu/drm/nouveau/nouveau_svm.c | 6 +- drivers/gpu/drm/nouveau/nouveau_svm.h | 3 +- include/linux/huge_mm.h | 18 +- include/linux/memremap.h | 29 +- include/linux/migrate.h | 2 + include/linux/mm.h | 1 + lib/test_hmm.c | 428 ++++++++++--- lib/test_hmm_uapi.h | 3 + mm/huge_memory.c | 261 ++++++-- mm/memory.c | 6 +- mm/memremap.c | 50 +- mm/migrate.c | 2 + mm/migrate_device.c | 488 ++++++++++++--- mm/page_alloc.c | 1 + mm/page_vma_mapped.c | 10 + mm/pgtable-generic.c | 6 + mm/rmap.c | 19 +- tools/testing/selftests/mm/hmm-tests.c | 805 ++++++++++++++++++++++++- 19 files changed, 2072 insertions(+), 312 deletions(-) -- 2.49.0
On 3 Jul 2025, at 18:27, Balbir Singh wrote: > This patch series adds support for THP migration of zone device pages. > To do so, the patches implement support for folio zone device pages > by adding support for setting up larger order pages. > > These patches build on the earlier posts by Ralph Campbell [1] > > Two new flags are added in vma_migration to select and mark compound pages. > migrate_vma_setup(), migrate_vma_pages() and migrate_vma_finalize() > support migration of these pages when MIGRATE_VMA_SELECT_COMPOUND > is passed in as arguments. > > The series also adds zone device awareness to (m)THP pages along > with fault handling of large zone device private pages. page vma walk > and the rmap code is also zone device aware. Support has also been > added for folios that might need to be split in the middle > of migration (when the src and dst do not agree on > MIGRATE_PFN_COMPOUND), that occurs when src side of the migration can > migrate large pages, but the destination has not been able to allocate > large pages. The code supported and used folio_split() when migrating > THP pages, this is used when MIGRATE_VMA_SELECT_COMPOUND is not passed > as an argument to migrate_vma_setup(). > > The test infrastructure lib/test_hmm.c has been enhanced to support THP > migration. A new ioctl to emulate failure of large page allocations has > been added to test the folio split code path. hmm-tests.c has new test > cases for huge page migration and to test the folio split path. A new > throughput test has been added as well. > > The nouveau dmem code has been enhanced to use the new THP migration > capability. > > Feedback from the RFC [2]: > > It was advised that prep_compound_page() not be exposed just for the purposes > of testing (test driver lib/test_hmm.c). Work arounds of copy and split the > folios did not work due to lock order dependency in the callback for > split folio. > > mTHP support: > > The patches hard code, HPAGE_PMD_NR in a few places, but the code has > been kept generic to support various order sizes. With additional > refactoring of the code support of different order sizes should be > possible. > > The future plan is to post enhancements to support mTHP with a rough > design as follows: > > 1. Add the notion of allowable thp orders to the HMM based test driver > 2. For non PMD based THP paths in migrate_device.c, check to see if > a suitable order is found and supported by the driver > 3. Iterate across orders to check the highest supported order for migration > 4. Migrate and finalize > > The mTHP patches can be built on top of this series, the key design elements > that need to be worked out are infrastructure and driver support for multiple > ordered pages and their migration. > > References: > [1] https://lore.kernel.org/linux-mm/20201106005147.20113-1-rcampbell@nvidia.com/ > [2] https://lore.kernel.org/linux-mm/20250306044239.3874247-3-balbirs@nvidia.com/T/ > > These patches are built on top of mm-unstable > > Cc: Karol Herbst <kherbst@redhat.com> > Cc: Lyude Paul <lyude@redhat.com> > Cc: Danilo Krummrich <dakr@kernel.org> > Cc: David Airlie <airlied@gmail.com> > Cc: Simona Vetter <simona@ffwll.ch> > Cc: "Jérôme Glisse" <jglisse@redhat.com> > Cc: Shuah Khan <shuah@kernel.org> > Cc: David Hildenbrand <david@redhat.com> > Cc: Barry Song <baohua@kernel.org> > Cc: Baolin Wang <baolin.wang@linux.alibaba.com> > Cc: Ryan Roberts <ryan.roberts@arm.com> > Cc: Matthew Wilcox <willy@infradead.org> > Cc: Peter Xu <peterx@redhat.com> > Cc: Zi Yan <ziy@nvidia.com> > Cc: Kefeng Wang <wangkefeng.wang@huawei.com> > Cc: Jane Chu <jane.chu@oracle.com> > Cc: Alistair Popple <apopple@nvidia.com> > Cc: Donet Tom <donettom@linux.ibm.com> > > Changelog v1: > - Changes from RFC [2], include support for handling fault_folio and using > trylock in the fault path > - A new test case has been added to measure the throughput improvement > - General refactoring of code to keep up with the changes in mm > - New split folio callback when the entire split is complete/done. The > callback is used to know when the head order needs to be reset. > > Testing: > - Testing was done with ZONE_DEVICE private pages on an x86 VM > - Throughput showed upto 5x improvement with THP migration, system to device > migration is slower due to the mirroring of data (see buffer->mirror) > > Balbir Singh (12): > mm/zone_device: support large zone device private folios > mm/migrate_device: flags for selecting device private THP pages > mm/thp: zone_device awareness in THP handling code > mm/migrate_device: THP migration of zone device pages > mm/memory/fault: Add support for zone device THP fault handling > lib/test_hmm: test cases and support for zone device private THP > mm/memremap: Add folio_split support > mm/thp: add split during migration support > lib/test_hmm: add test case for split pages > selftests/mm/hmm-tests: new tests for zone device THP migration > gpu/drm/nouveau: Add THP migration support > selftests/mm/hmm-tests: New throughput tests including THP > > drivers/gpu/drm/nouveau/nouveau_dmem.c | 246 +++++--- > drivers/gpu/drm/nouveau/nouveau_svm.c | 6 +- > drivers/gpu/drm/nouveau/nouveau_svm.h | 3 +- > include/linux/huge_mm.h | 18 +- > include/linux/memremap.h | 29 +- > include/linux/migrate.h | 2 + > include/linux/mm.h | 1 + > lib/test_hmm.c | 428 ++++++++++--- > lib/test_hmm_uapi.h | 3 + > mm/huge_memory.c | 261 ++++++-- > mm/memory.c | 6 +- > mm/memremap.c | 50 +- > mm/migrate.c | 2 + > mm/migrate_device.c | 488 ++++++++++++--- > mm/page_alloc.c | 1 + > mm/page_vma_mapped.c | 10 + > mm/pgtable-generic.c | 6 + > mm/rmap.c | 19 +- > tools/testing/selftests/mm/hmm-tests.c | 805 ++++++++++++++++++++++++- > 19 files changed, 2072 insertions(+), 312 deletions(-) > I only got the cover letter. Did you forget to send the actual patches? Thanks. Best Regards, Yan, Zi
On 7/4/25 09:00, Zi Yan wrote: > On 3 Jul 2025, at 18:27, Balbir Singh wrote: > >> This patch series adds support for THP migration of zone device pages. >> To do so, the patches implement support for folio zone device pages >> by adding support for setting up larger order pages. >> >> These patches build on the earlier posts by Ralph Campbell [1] >> >> Two new flags are added in vma_migration to select and mark compound pages. >> migrate_vma_setup(), migrate_vma_pages() and migrate_vma_finalize() >> support migration of these pages when MIGRATE_VMA_SELECT_COMPOUND >> is passed in as arguments. >> >> The series also adds zone device awareness to (m)THP pages along >> with fault handling of large zone device private pages. page vma walk >> and the rmap code is also zone device aware. Support has also been >> added for folios that might need to be split in the middle >> of migration (when the src and dst do not agree on >> MIGRATE_PFN_COMPOUND), that occurs when src side of the migration can >> migrate large pages, but the destination has not been able to allocate >> large pages. The code supported and used folio_split() when migrating >> THP pages, this is used when MIGRATE_VMA_SELECT_COMPOUND is not passed >> as an argument to migrate_vma_setup(). >> >> The test infrastructure lib/test_hmm.c has been enhanced to support THP >> migration. A new ioctl to emulate failure of large page allocations has >> been added to test the folio split code path. hmm-tests.c has new test >> cases for huge page migration and to test the folio split path. A new >> throughput test has been added as well. >> >> The nouveau dmem code has been enhanced to use the new THP migration >> capability. >> >> Feedback from the RFC [2]: >> >> It was advised that prep_compound_page() not be exposed just for the purposes >> of testing (test driver lib/test_hmm.c). Work arounds of copy and split the >> folios did not work due to lock order dependency in the callback for >> split folio. >> >> mTHP support: >> >> The patches hard code, HPAGE_PMD_NR in a few places, but the code has >> been kept generic to support various order sizes. With additional >> refactoring of the code support of different order sizes should be >> possible. >> >> The future plan is to post enhancements to support mTHP with a rough >> design as follows: >> >> 1. Add the notion of allowable thp orders to the HMM based test driver >> 2. For non PMD based THP paths in migrate_device.c, check to see if >> a suitable order is found and supported by the driver >> 3. Iterate across orders to check the highest supported order for migration >> 4. Migrate and finalize >> >> The mTHP patches can be built on top of this series, the key design elements >> that need to be worked out are infrastructure and driver support for multiple >> ordered pages and their migration. >> >> References: >> [1] https://lore.kernel.org/linux-mm/20201106005147.20113-1-rcampbell@nvidia.com/ >> [2] https://lore.kernel.org/linux-mm/20250306044239.3874247-3-balbirs@nvidia.com/T/ >> >> These patches are built on top of mm-unstable >> >> Cc: Karol Herbst <kherbst@redhat.com> >> Cc: Lyude Paul <lyude@redhat.com> >> Cc: Danilo Krummrich <dakr@kernel.org> >> Cc: David Airlie <airlied@gmail.com> >> Cc: Simona Vetter <simona@ffwll.ch> >> Cc: "Jérôme Glisse" <jglisse@redhat.com> >> Cc: Shuah Khan <shuah@kernel.org> >> Cc: David Hildenbrand <david@redhat.com> >> Cc: Barry Song <baohua@kernel.org> >> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> >> Cc: Ryan Roberts <ryan.roberts@arm.com> >> Cc: Matthew Wilcox <willy@infradead.org> >> Cc: Peter Xu <peterx@redhat.com> >> Cc: Zi Yan <ziy@nvidia.com> >> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> >> Cc: Jane Chu <jane.chu@oracle.com> >> Cc: Alistair Popple <apopple@nvidia.com> >> Cc: Donet Tom <donettom@linux.ibm.com> >> >> Changelog v1: >> - Changes from RFC [2], include support for handling fault_folio and using >> trylock in the fault path >> - A new test case has been added to measure the throughput improvement >> - General refactoring of code to keep up with the changes in mm >> - New split folio callback when the entire split is complete/done. The >> callback is used to know when the head order needs to be reset. >> >> Testing: >> - Testing was done with ZONE_DEVICE private pages on an x86 VM >> - Throughput showed upto 5x improvement with THP migration, system to device >> migration is slower due to the mirroring of data (see buffer->mirror) >> >> Balbir Singh (12): >> mm/zone_device: support large zone device private folios >> mm/migrate_device: flags for selecting device private THP pages >> mm/thp: zone_device awareness in THP handling code >> mm/migrate_device: THP migration of zone device pages >> mm/memory/fault: Add support for zone device THP fault handling >> lib/test_hmm: test cases and support for zone device private THP >> mm/memremap: Add folio_split support >> mm/thp: add split during migration support >> lib/test_hmm: add test case for split pages >> selftests/mm/hmm-tests: new tests for zone device THP migration >> gpu/drm/nouveau: Add THP migration support >> selftests/mm/hmm-tests: New throughput tests including THP >> >> drivers/gpu/drm/nouveau/nouveau_dmem.c | 246 +++++--- >> drivers/gpu/drm/nouveau/nouveau_svm.c | 6 +- >> drivers/gpu/drm/nouveau/nouveau_svm.h | 3 +- >> include/linux/huge_mm.h | 18 +- >> include/linux/memremap.h | 29 +- >> include/linux/migrate.h | 2 + >> include/linux/mm.h | 1 + >> lib/test_hmm.c | 428 ++++++++++--- >> lib/test_hmm_uapi.h | 3 + >> mm/huge_memory.c | 261 ++++++-- >> mm/memory.c | 6 +- >> mm/memremap.c | 50 +- >> mm/migrate.c | 2 + >> mm/migrate_device.c | 488 ++++++++++++--- >> mm/page_alloc.c | 1 + >> mm/page_vma_mapped.c | 10 + >> mm/pgtable-generic.c | 6 + >> mm/rmap.c | 19 +- >> tools/testing/selftests/mm/hmm-tests.c | 805 ++++++++++++++++++++++++- >> 19 files changed, 2072 insertions(+), 312 deletions(-) >> > > I only got the cover letter. Did you forget to send the actual patches? > A script of mine stripped the cc from the actual patches (my bad), the rest went to linux-mm and linux-kernel. I can resend if needed Balbir
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