A new iteration of this patchset, previously known as write streams. Instead of exposing numeric values for streams, I've previously advocated for just doing a set of hints that makes sense instead. See the coverage from the LSFMM summit this year: https://lwn.net/Articles/717755/ This patchset attempts to do that. We define 4 flags for the pwritev2 system call: RWF_WRITE_LIFE_SHORT Data written with this flag is expected to have a high overwrite rate, or life time. RWF_WRITE_LIFE_MEDIUM Longer life time than SHORT RWF_WRITE_LIFE_LONG Longer life time than MEDIUM RWF_WRITE_LIFE_EXTREME Longer life time than LONG The idea is that these are relative values, so an application can use them as they see fit. The underlying device can then place data appropriately, or be free to ignore the hint. It's just a hint. Comments appreciated. A branch based on current master can be pulled from here: git://git.kernel.dk/linux-block write-stream.1 -- Jens Axboe
