[PATCH v6 01/13] mm/migrate_device: Introduce migrate_pfn_from_page() helper
From: Jordan Niethe <hidden>
Date: 2026-02-02 11:36:52
Also in:
dri-devel, intel-xe, linux-mm, lkml
Subsystem:
amd kfd, drm driver for nvidia geforce/quadro gpus, drm drivers, drm drivers and misc gpu patches, hmm - heterogeneous memory management, kernel virtual machine for powerpc (kvm/powerpc), library code, linux for powerpc (32-bit and 64-bit), memory management, memory management - memory policy and migration, radeon and amdgpu drm drivers, the rest · Maintainers:
Felix Kuehling, Lyude Paul, Danilo Krummrich, David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Jason Gunthorpe, Leon Romanovsky, Madhavan Srinivasan, Andrew Morton, Michael Ellerman, David Hildenbrand, Alex Deucher, Christian König, Linus Torvalds
To create a migrate entry from a given struct page, that page is first
converted to its pfn, before passing the pfn to migrate_pfn().
A future change will remove device private pages from the physical
address space. This will mean that device private pages no longer have a
pfn and must be handled separately.
Prepare for this with a new helper:
- migrate_pfn_from_page()
This helper takes a struct page as parameter instead of a pfn. This will
allow more flexibility for handling the mpfn differently for device
private pages.
Reviewed-by: Balbir Singh <redacted>
Acked-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Jordan Niethe <redacted>
---
v2: New to series
v3: No change
---
arch/powerpc/kvm/book3s_hv_uvmem.c | 2 +-
drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 2 +-
drivers/gpu/drm/drm_pagemap.c | 2 +-
drivers/gpu/drm/nouveau/nouveau_dmem.c | 4 ++--
include/linux/migrate.h | 5 +++++
lib/test_hmm.c | 11 ++++++-----
mm/migrate_device.c | 7 +++----
7 files changed, 19 insertions(+), 14 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index 7cf9310de0ec..47abc220ae03 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c@@ -784,7 +784,7 @@ static int kvmppc_svm_page_in(struct vm_area_struct *vma, } } - *mig.dst = migrate_pfn(page_to_pfn(dpage)); + *mig.dst = migrate_pfn_from_page(dpage); migrate_vma_pages(&mig); out_finalize: migrate_vma_finalize(&mig);
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index b021f1e56114..297fa108ccf9 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c@@ -652,7 +652,7 @@ svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange, pr_debug_ratelimited("dma mapping dst to 0x%llx, pfn 0x%lx\n", dst[i] >> PAGE_SHIFT, page_to_pfn(dpage)); - migrate->dst[i] = migrate_pfn(page_to_pfn(dpage)); + migrate->dst[i] = migrate_pfn_from_page(dpage); j++; }
diff --git a/drivers/gpu/drm/drm_pagemap.c b/drivers/gpu/drm/drm_pagemap.c
index 38eca94f01a1..f5e76c75e609 100644
--- a/drivers/gpu/drm/drm_pagemap.c
+++ b/drivers/gpu/drm/drm_pagemap.c@@ -742,7 +742,7 @@ static int drm_pagemap_migrate_populate_ram_pfn(struct vm_area_struct *vas, goto free_pages; page = folio_page(folio, 0); - mpfn[i] = migrate_pfn(page_to_pfn(page)); + mpfn[i] = migrate_pfn_from_page(page); next: if (page)
diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index 3d8031296eed..3448e27bd42f 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c@@ -249,7 +249,7 @@ static vm_fault_t nouveau_dmem_migrate_to_ram(struct vm_fault *vmf) goto done; } - args.dst[0] = migrate_pfn(page_to_pfn(dpage)); + args.dst[0] = migrate_pfn_from_page(dpage); if (order) args.dst[0] |= MIGRATE_PFN_COMPOUND; dfolio = page_folio(dpage);
@@ -766,7 +766,7 @@ static unsigned long nouveau_dmem_migrate_copy_one(struct nouveau_drm *drm, ((paddr >> PAGE_SHIFT) << NVIF_VMM_PFNMAP_V0_ADDR_SHIFT); if (src & MIGRATE_PFN_WRITE) *pfn |= NVIF_VMM_PFNMAP_V0_W; - mpfn = migrate_pfn(page_to_pfn(dpage)); + mpfn = migrate_pfn_from_page(dpage); if (folio_order(page_folio(dpage))) mpfn |= MIGRATE_PFN_COMPOUND; return mpfn;
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 26ca00c325d9..d269ec1400be 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h@@ -140,6 +140,11 @@ static inline unsigned long migrate_pfn(unsigned long pfn) return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID; } +static inline unsigned long migrate_pfn_from_page(struct page *page) +{ + return migrate_pfn(page_to_pfn(page)); +} + enum migrate_vma_direction { MIGRATE_VMA_SELECT_SYSTEM = 1 << 0, MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 455a6862ae50..0cc3ba9b0502 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c@@ -729,7 +729,8 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args, rpage = BACKING_PAGE(dpage); rpage->zone_device_data = dmirror; - *dst = migrate_pfn(page_to_pfn(dpage)) | write; + *dst = migrate_pfn_from_page(dpage) | + write; src_page = pfn_to_page(spfn + i); if (spage)
@@ -756,7 +757,7 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args, pr_debug("migrating from sys to dev pfn src: 0x%lx pfn dst: 0x%lx\n", page_to_pfn(spage), page_to_pfn(dpage)); - *dst = migrate_pfn(page_to_pfn(dpage)) | write; + *dst = migrate_pfn_from_page(dpage) | write; if (is_large) { int i;
@@ -991,7 +992,7 @@ static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args, if (dpage) { lock_page(dpage); - *dst |= migrate_pfn(page_to_pfn(dpage)); + *dst |= migrate_pfn_from_page(dpage); } for (i = 0; i < (1 << order); i++) {
@@ -1002,7 +1003,7 @@ static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args, if (!dpage && order) { dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr); lock_page(dpage); - dst[i] = migrate_pfn(page_to_pfn(dpage)); + dst[i] = migrate_pfn_from_page(dpage); dst_page = pfn_to_page(page_to_pfn(dpage)); dpage = NULL; /* For the next iteration */ } else {
@@ -1414,7 +1415,7 @@ static void dmirror_device_evict_chunk(struct dmirror_chunk *chunk) /* TODO Support splitting here */ lock_page(dpage); - dst_pfns[i] = migrate_pfn(page_to_pfn(dpage)); + dst_pfns[i] = migrate_pfn_from_page(dpage); if (src_pfns[i] & MIGRATE_PFN_WRITE) dst_pfns[i] |= MIGRATE_PFN_WRITE; if (order)
diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 23379663b1e1..1a2067f830da 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c@@ -207,9 +207,8 @@ static int migrate_vma_collect_huge_pmd(pmd_t *pmdp, unsigned long start, .vma = walk->vma, }; - unsigned long pfn = page_to_pfn(folio_page(folio, 0)); - - migrate->src[migrate->npages] = migrate_pfn(pfn) | write + migrate->src[migrate->npages] = migrate_pfn_from_page(folio_page(folio, 0)) + | write | MIGRATE_PFN_MIGRATE | MIGRATE_PFN_COMPOUND; migrate->dst[migrate->npages++] = 0;
@@ -328,7 +327,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, goto again; } - mpfn = migrate_pfn(page_to_pfn(page)) | + mpfn = migrate_pfn_from_page(page) | MIGRATE_PFN_MIGRATE; if (softleaf_is_device_private_write(entry)) mpfn |= MIGRATE_PFN_WRITE;
--
2.34.1