Commit ab09243a authored by Alistair Popple's avatar Alistair Popple Committed by Linus Torvalds
Browse files

mm/migrate.c: remove MIGRATE_PFN_LOCKED 

MIGRATE_PFN_LOCKED is used to indicate to migrate_vma_prepare() that a
source page was already locked during migrate_vma_collect().  If it
wasn't then the a second attempt is made to lock the page.  However if
the first attempt failed it's unlikely a second attempt will succeed,
and the retry adds complexity.  So clean this up by removing the retry
and MIGRATE_PFN_LOCKED flag.

Destination pages are also meant to have the MIGRATE_PFN_LOCKED flag
set, but nothing actually checks that.

Link: https://lkml.kernel.org/r/20211025041608.289017-1-apopple@nvidia.com


Signed-off-by: default avatarAlistair Popple <apopple@nvidia.com>
Reviewed-by: default avatarRalph Campbell <rcampbell@nvidia.com>
Acked-by: default avatarFelix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0ef02462

Documentation/vm/hmm.rst

+1 −1
Original line number Original line Diff line number Diff line
@@ -360,7 +360,7 @@ between device driver specific code and shared common code: 
   system memory page, locks the page with ``lock_page()``, and fills in the

   system memory page, locks the page with ``lock_page()``, and fills in the

   ``dst`` array entry with::

   ``dst`` array entry with::





     dst[i] = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;

     dst[i] = migrate_pfn(page_to_pfn(dpage));





   Now that the driver knows that this page is being migrated, it can

   Now that the driver knows that this page is being migrated, it can

   invalidate device private MMU mappings and copy device private memory

   invalidate device private MMU mappings and copy device private memory

arch/powerpc/kvm/book3s_hv_uvmem.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -560,7 +560,7 @@ static int __kvmppc_svm_page_out(struct vm_area_struct *vma, 
				  gpa, 0, page_shift);

				  gpa, 0, page_shift);





	if (ret == U_SUCCESS)

	if (ret == U_SUCCESS)

		*mig.dst = migrate_pfn(pfn) | MIGRATE_PFN_LOCKED;

		*mig.dst = migrate_pfn(pfn);

	else {

	else {

		unlock_page(dpage);

		unlock_page(dpage);

		__free_page(dpage);

		__free_page(dpage);
@@ -774,7 +774,7 @@ static int kvmppc_svm_page_in(struct vm_area_struct *vma, 
		}

		}

	}

	}





	*mig.dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;

	*mig.dst = migrate_pfn(page_to_pfn(dpage));

	migrate_vma_pages(&mig);

	migrate_vma_pages(&mig);

out_finalize:

out_finalize:

	migrate_vma_finalize(&mig);

	migrate_vma_finalize(&mig);

drivers/gpu/drm/amd/amdkfd/kfd_migrate.c

+0 −2
Original line number Original line Diff line number Diff line
@@ -317,7 +317,6 @@ svm_migrate_copy_to_vram(struct amdgpu_device *adev, struct svm_range *prange, 
			migrate->dst[i] = svm_migrate_addr_to_pfn(adev, dst[i]);

			migrate->dst[i] = svm_migrate_addr_to_pfn(adev, dst[i]);

			svm_migrate_get_vram_page(prange, migrate->dst[i]);

			svm_migrate_get_vram_page(prange, migrate->dst[i]);

			migrate->dst[i] = migrate_pfn(migrate->dst[i]);

			migrate->dst[i] = migrate_pfn(migrate->dst[i]);

			migrate->dst[i] |= MIGRATE_PFN_LOCKED;

			src[i] = dma_map_page(dev, spage, 0, PAGE_SIZE,

			src[i] = dma_map_page(dev, spage, 0, PAGE_SIZE,

					      DMA_TO_DEVICE);

					      DMA_TO_DEVICE);

			r = dma_mapping_error(dev, src[i]);

			r = dma_mapping_error(dev, src[i]);
@@ -610,7 +609,6 @@ svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange, 
				     dst[i] >> PAGE_SHIFT, page_to_pfn(dpage));

				     dst[i] >> PAGE_SHIFT, page_to_pfn(dpage));





		migrate->dst[i] = migrate_pfn(page_to_pfn(dpage));

		migrate->dst[i] = migrate_pfn(page_to_pfn(dpage));

		migrate->dst[i] |= MIGRATE_PFN_LOCKED;

		j++;

		j++;

	}

	}

drivers/gpu/drm/nouveau/nouveau_dmem.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -166,7 +166,7 @@ static vm_fault_t nouveau_dmem_fault_copy_one(struct nouveau_drm *drm, 
		goto error_dma_unmap;

		goto error_dma_unmap;

	mutex_unlock(&svmm->mutex);

	mutex_unlock(&svmm->mutex);





	args->dst[0] = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;

	args->dst[0] = migrate_pfn(page_to_pfn(dpage));

	return 0;

	return 0;





error_dma_unmap:

error_dma_unmap:
@@ -602,7 +602,7 @@ static unsigned long nouveau_dmem_migrate_copy_one(struct nouveau_drm *drm, 
		((paddr >> PAGE_SHIFT) << NVIF_VMM_PFNMAP_V0_ADDR_SHIFT);

		((paddr >> PAGE_SHIFT) << NVIF_VMM_PFNMAP_V0_ADDR_SHIFT);

	if (src & MIGRATE_PFN_WRITE)

	if (src & MIGRATE_PFN_WRITE)

		*pfn |= NVIF_VMM_PFNMAP_V0_W;

		*pfn |= NVIF_VMM_PFNMAP_V0_W;

	return migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;

	return migrate_pfn(page_to_pfn(dpage));





out_dma_unmap:

out_dma_unmap:

	dma_unmap_page(dev, *dma_addr, PAGE_SIZE, DMA_BIDIRECTIONAL);

	dma_unmap_page(dev, *dma_addr, PAGE_SIZE, DMA_BIDIRECTIONAL);

include/linux/migrate.h

+0 −1
Original line number Original line Diff line number Diff line
@@ -110,7 +110,6 @@ static inline int migrate_misplaced_page(struct page *page, 
 */

 */

#define MIGRATE_PFN_VALID	(1UL << 0)

#define MIGRATE_PFN_VALID	(1UL << 0)

#define MIGRATE_PFN_MIGRATE	(1UL << 1)

#define MIGRATE_PFN_MIGRATE	(1UL << 1)

#define MIGRATE_PFN_LOCKED	(1UL << 2)

#define MIGRATE_PFN_WRITE	(1UL << 3)

#define MIGRATE_PFN_WRITE	(1UL << 3)

#define MIGRATE_PFN_SHIFT	6

#define MIGRATE_PFN_SHIFT	6