include/linux/migrate_mode.h

   1 #ifndef MIGRATE_MODE_H_INCLUDED
   2 #define MIGRATE_MODE_H_INCLUDED
   3 /*
   4  * MIGRATE_ASYNC means never block
   5  * MIGRATE_SYNC_LIGHT in the current implementation means to allow blocking
   6  *      on most operations but not ->writepage as the potential stall time
   7  *      is too significant
   8  * MIGRATE_SYNC will block when migrating pages
   9  * MIGRATE_SYNC_NO_COPY will block when migrating pages but will not copy pages
  10  *      with the CPU. Instead, page copy happens outside the migratepage()
  11  *      callback and is likely using a DMA engine. See migrate_vma() and HMM
  12  *      (mm/hmm.c) for users of this mode.
  13  */
  14 enum migrate_mode {
  15         MIGRATE_ASYNC,
  16         MIGRATE_SYNC_LIGHT,
  17         MIGRATE_SYNC,
  18         MIGRATE_SYNC_NO_COPY,
  19 };
  20
  21 #endif          /* MIGRATE_MODE_H_INCLUDED */