Commit dd19e6d8 authored by Alex Sierra's avatar Alex Sierra Committed by Andrew Morton
Browse files

mm: add device coherent vma selection for memory migration 

This case is used to migrate pages from device memory, back to system
memory.  Device coherent type memory is cache coherent from device and CPU
point of view.

Link: https://lkml.kernel.org/r/20220715150521.18165-6-alex.sierra@amd.com


Signed-off-by: default avatarAlex Sierra <alex.sierra@amd.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarFelix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: default avatarAlistair Poppple <apopple@nvidia.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 3218f871

include/linux/migrate.h

+1 −0
Original line number Diff line number Diff line
@@ -148,6 +148,7 @@ static inline unsigned long migrate_pfn(unsigned long pfn) 
enum migrate_vma_direction {

	MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,

	MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,

	MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,

};



struct migrate_vma {

mm/migrate_device.c

+9 −3
Original line number Diff line number Diff line
@@ -148,15 +148,21 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, 
			if (is_writable_device_private_entry(entry))

				mpfn |= MIGRATE_PFN_WRITE;

		} else {

			if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))

				goto next;

			pfn = pte_pfn(pte);

			if (is_zero_pfn(pfn)) {

			if (is_zero_pfn(pfn) &&

			    (migrate->flags & MIGRATE_VMA_SELECT_SYSTEM)) {

				mpfn = MIGRATE_PFN_MIGRATE;

				migrate->cpages++;

				goto next;

			}

			page = vm_normal_page(migrate->vma, addr, pte);

			if (page && !is_zone_device_page(page) &&

			    !(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))

				goto next;

			else if (page && is_device_coherent_page(page) &&

			    (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_COHERENT) ||

			     page->pgmap->owner != migrate->pgmap_owner))

				goto next;

			mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;

			mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;

		}