The flusher threads

The write back cache defers I/O data operations in the page cache. A set or kernel threads, called flusher threads, are responsible for that. Dirty page write back occurs when any one of the following situations is satisfied:

  • When free memory falls below a specified threshold to regain memory consumed by dirty pages.
  • When dirty data lasts until a specific period. The oldest data is written back to the disk to ensure that dirty data does not remain dirty indefinitely.
  • When a user process invokes the sync() and fsync() system calls. This is an on-demand write back.

Get Linux Device Drivers Development now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.