Volatile ranges with fallocate()

Posted Jun 8, 2012 0:35 UTC (Fri) by dlang (guest, #313)
In reply to: Volatile ranges with fallocate() by robert_s
Parent article: Volatile ranges with fallocate()

to answer your second issue (how would it know that it's been reclaimed), per the article, the application does

fallocate(fd, FALLOCATE_FL_UNMARK_VOLATILE, offset, len);

and if the return code is 0, it can use the data, if the return code is non-zero, some part of the data has been reclaimed and the application needs to regenerate it.

I would hope that when the system grabs part of a block that's been marked volatile, it grabs the entire block, rather then just punching a small hole in it (or at least remembers what it damaged earlier when it needs more memory, on the theory that you may mark a large block volitile and then try to re-use small chunks of it)