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mm: add device coherent vma selection for memory migration

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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: Alex Sierra <alex.sierra@amd.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alistair Poppple <apopple@nvidia.com>
Reviewed-by: David 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: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Alex Sierra 2022-07-15 10:05:12 -05:00 committed by akpm
parent 3218f8712d
commit dd19e6d8ff
2 changed files with 10 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/linux/migrate.h
View File

@ -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 {

12
mm/migrate_device.c
View File

@ -148,15 +148,21 @@ again:
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;
}