diff options
Diffstat (limited to 'include/linux/migrate.h')
| -rw-r--r-- | include/linux/migrate.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 8dc8f0a3f1af..d4e6d12a0b40 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -218,6 +218,15 @@ static inline unsigned long migrate_pfn(unsigned long pfn) * driver should avoid setting MIGRATE_PFN_ERROR unless it is really in an * unrecoverable state. * + * For empty entry inside CPU page table (pte_none() or pmd_none() is true) we + * do set MIGRATE_PFN_MIGRATE flag inside the corresponding source array thus + * allowing device driver to allocate device memory for those unback virtual + * address. For this the device driver simply have to allocate device memory + * and properly set the destination entry like for regular migration. Note that + * this can still fails and thus inside the device driver must check if the + * migration was successful for those entry inside the finalize_and_map() + * callback just like for regular migration. + * * THE alloc_and_copy() CALLBACK MUST NOT CHANGE ANY OF THE SRC ARRAY ENTRIES * OR BAD THINGS WILL HAPPEN ! * |