On 2017/11/9 13:51, Hyunchul Lee wrote: > From: Hyunchul Lee <cheol....@lge.com> > > Using write hints[1], applications can inform the life time of the data > written to devices. and this[2] reported that the write hints patch > decreased writes in NAND by 25%. > > This hints help F2FS to determine the followings. > 1) the segment types where the data will be written. > 2) the hints that will be passed down to devices with the data of segments. > > This patch set implements the first mapping from write hints to segment types > as shown below. > > hints segment type > ----- ------------ > WRITE_LIFE_SHORT CURSEG_COLD_DATA > WRITE_LIFE_EXTREME CURSEG_HOT_DATA > others CURSEG_WARM_DATA > > The F2FS poliy for hot/cold seperation has precedence over this hints, And > hints are not applied in in-place update.
Could we change to disable IPU if file/inode write hint is existing? > > Before the second mapping is implemented, write hints are not passed down > to devices. Because it is better that the data of a segment have the same > hint. > > [1]: c75b1d9421f80f4143e389d2d50ddfc8a28c8c35 > [2]: https://lwn.net/Articles/726477/ Could you write a patch to support passing write hint to block layer for buffered writes as below commit: 0127251c45ae ("ext4: add support for passing in write hints for buffered writes") Thanks, > > Hyunchul Lee (2): > f2fs: apply write hints to select the type of segments for buffered > write > f2fs: apply write hints to select the type of segment for direct write > > fs/f2fs/data.c | 101 > ++++++++++++++++++++++++++++++++---------------------- > fs/f2fs/f2fs.h | 1 + > fs/f2fs/segment.c | 14 +++++++- > 3 files changed, 74 insertions(+), 42 deletions(-) >
