diff options
Diffstat (limited to 'include/linux/mm_types.h')
| -rw-r--r-- | include/linux/mm_types.h | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 3a37a89eb7a7..6a7a1083b6fb 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -159,7 +159,16 @@ struct page { /** @pgmap: Points to the hosting device page map. */ struct dev_pagemap *pgmap; void *zone_device_data; - unsigned long _zd_pad_1; /* uses mapping */ + /* + * ZONE_DEVICE private pages are counted as being + * mapped so the next 3 words hold the mapping, index, + * and private fields from the source anonymous or + * page cache page while the page is migrated to device + * private memory. + * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also + * use the mapping, index, and private fields when + * pmem backed DAX files are mapped. + */ }; /** @rcu_head: You can use this to free a page by RCU. */ |