From f25cbb7a95a24ff9a2a3bebd308e303942ae6b2c Mon Sep 17 00:00:00 2001 From: Alex Sierra Date: Fri, 15 Jul 2022 10:05:10 -0500 Subject: mm: add zone device coherent type memory support Device memory that is cache coherent from device and CPU point of view. This is used on platforms that have an advanced system bus (like CAPI or CXL). Any page of a process can be migrated to such memory. However, no one should be allowed to pin such memory so that it can always be evicted. [hch@lst.de: rebased ontop of the refcount changes, remove is_dev_private_or_coherent_page] Link: https://lkml.kernel.org/r/20220715150521.18165-4-alex.sierra@amd.com Signed-off-by: Alex Sierra Signed-off-by: Christoph Hellwig Acked-by: Felix Kuehling Reviewed-by: Alistair Popple Acked-by: David Hildenbrand Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: Matthew Wilcox Cc: Ralph Campbell Signed-off-by: Andrew Morton --- mm/migrate_device.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'mm/migrate_device.c') diff --git a/mm/migrate_device.c b/mm/migrate_device.c index 5052093d0262..a4847ad65da3 100644 --- a/mm/migrate_device.c +++ b/mm/migrate_device.c @@ -518,7 +518,7 @@ EXPORT_SYMBOL(migrate_vma_setup); * handle_pte_fault() * do_anonymous_page() * to map in an anonymous zero page but the struct page will be a ZONE_DEVICE - * private page. + * private or coherent page. */ static void migrate_vma_insert_page(struct migrate_vma *migrate, unsigned long addr, @@ -594,11 +594,8 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate, page_to_pfn(page)); entry = swp_entry_to_pte(swp_entry); } else { - /* - * For now we only support migrating to un-addressable device - * memory. - */ - if (is_zone_device_page(page)) { + if (is_zone_device_page(page) && + !is_device_coherent_page(page)) { pr_warn_once("Unsupported ZONE_DEVICE page type.\n"); goto abort; } @@ -701,10 +698,11 @@ void migrate_vma_pages(struct migrate_vma *migrate) mapping = page_mapping(page); - if (is_device_private_page(newpage)) { + if (is_device_private_page(newpage) || + is_device_coherent_page(newpage)) { /* - * For now only support private anonymous when migrating - * to un-addressable device memory. + * For now only support anonymous memory migrating to + * device private or coherent memory. */ if (mapping) { migrate->src[i] &= ~MIGRATE_PFN_MIGRATE; -- cgit v1.2.3-59-g8ed1b