diff options
| author | Balbir Singh <balbirs@nvidia.com> | 2025-10-01 16:57:02 +1000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-11-24 15:08:48 -0800 |
| commit | 4265d67e405a41562634279ca1ededf79fdadcd7 (patch) | |
| tree | 62c4f2568c9a23e147b13b93ae9fa7a601fc55e3 /lib/test_hmm.c | |
| parent | 56ef398996435a0021569b86293d376649f12540 (diff) | |
mm/migrate_device: add THP splitting during migration
Implement migrate_vma_split_pages() to handle THP splitting during the
migration process when destination cannot allocate compound pages.
This addresses the common scenario where migrate_vma_setup() succeeds with
MIGRATE_PFN_COMPOUND pages, but the destination device cannot allocate
large pages during the migration phase.
Key changes:
- migrate_vma_split_pages(): Split already-isolated pages during migration
- Enhanced folio_split() and __split_unmapped_folio() with isolated
parameter to avoid redundant unmap/remap operations
This provides a fallback mechansim to ensure migration succeeds even when
large page allocation fails at the destination.
[matthew.brost@intel.com: add THP splitting during migration]
Link: https://lkml.kernel.org/r/20251120230825.181072-2-matthew.brost@intel.com
Link: https://lkml.kernel.org/r/20251001065707.920170-12-balbirs@nvidia.com
Signed-off-by: Balbir Singh <balbirs@nvidia.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
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: Ralph Campbell <rcampbell@nvidia.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib/test_hmm.c')
| -rw-r--r-- | lib/test_hmm.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/lib/test_hmm.c b/lib/test_hmm.c index 46fa9e200db8..df429670633e 100644 --- a/lib/test_hmm.c +++ b/lib/test_hmm.c @@ -1613,6 +1613,15 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf) nr = 1 << order; /* + * When folios are partially mapped, we can't rely on the folio + * order of vmf->page as the folio might not be fully split yet + */ + if (vmf->pte) { + order = 0; + nr = 1; + } + + /* * Consider a per-cpu cache of src and dst pfns, but with * large number of cpus that might not scale well. */ |