From: Hyunchul Lee <cheol....@lge.com>
This set implements passing down write hints to block layer with the
following mapping. This mapping equals the conclusion from discussion in
the link, https://sourceforge.net/p/linux-f2fs/mailman/message/36170969/
But there are two exceptions. (1) the 'iohint_mode' mount option is changed
to 'whint_mode'. (2) in "user-based" mode, WRITE_LIFE_EXTREME is passed
down instead of WRITE_LIFE_NOT_SET for files flagged with ioctl(COLD) and
extension list.
Sorry for late patch.
1) whint_mode=off. F2FS only passes down WRITE_LIFE_NOT_SET.
2) whint_mode=user-based. F2FS tries to pass down hints given by
users.
User F2FS Block
---- ---- -----
META WRITE_LIFE_NOT_SET
HOT_NODE "
WARM_NODE "
COLD_NODE "
*ioctl(COLD) COLD_DATA WRITE_LIFE_EXTREME
*extension list " "
-- buffered io
WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME
WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT
WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_NOT_SET
WRITE_LIFE_NONE " "
WRITE_LIFE_MEDIUM " "
WRITE_LIFE_LONG " "
-- direct io
WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME
WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT
WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_NOT_SET
WRITE_LIFE_NONE " WRITE_LIFE_NONE
WRITE_LIFE_MEDIUM " WRITE_LIFE_MEDIUM
WRITE_LIFE_LONG " WRITE_LIFE_LONG
3) whint_mode=fs-based. F2FS passes down hints with its policy.
User F2FS Block
---- ---- -----
META WRITE_LIFE_MEDIUM;
HOT_NODE WRITE_LIFE_NOT_SET
WARM_NODE "
COLD_NODE WRITE_LIFE_NONE
ioctl(COLD) COLD_DATA WRITE_LIFE_EXTREME
extension list " "
-- buffered io
WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME
WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT
WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_LONG
WRITE_LIFE_NONE " "
WRITE_LIFE_MEDIUM " "
WRITE_LIFE_LONG " "
-- direct io
WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME
WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT
WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_NOT_SET
WRITE_LIFE_NONE " WRITE_LIFE_NONE
WRITE_LIFE_MEDIUM " WRITE_LIFE_MEDIUM
WRITE_LIFE_LONG " WRITE_LIFE_LONG
Hyunchul Lee (3):
f2fs: support passing down write hints given by users to block layer
f2fs: support passing down write hints to block layer with F2FS policy
f2fs: Add the 'whint_mode' mount option to f2fs documentation
Documentation/filesystems/f2fs.txt | 6 +++
fs/f2fs/data.c | 27 ++++++++--
fs/f2fs/f2fs.h | 10 ++++
fs/f2fs/segment.c | 104 +++++++++++++++++++++++++++++++++++++
fs/f2fs/super.c | 29 ++++++++++-
5 files changed, 170 insertions(+), 6 deletions(-)
--
1.9.1
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