Messages in this thread | | | Date | Thu, 9 Nov 2017 10:16:24 -0800 | From | Jaegeuk Kim <> | Subject | Re: [RFC PATCH 0/2] apply write hints to select the type of segments |
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On 11/09, Chao Yu wrote: > On 2017/11/9 13:51, Hyunchul Lee wrote: > > From: Hyunchul Lee <cheol.lee@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?
Well, this is a hint which is not related to IPU. I think user should be aware of controlling IPU.
> > > > 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(-) > >
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