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authorHyunchul Lee <cheol.lee@lge.com>2018-01-31 11:36:59 +0900
committerJaegeuk Kim <jaegeuk@kernel.org>2018-03-13 08:05:37 +0900
commit8b3a0ca0fde161c9716d4f0e8d81bf30fc004604 (patch)
treecf68663de719b8b06d3c28b74f2a1927382e3cc5 /Documentation/filesystems
parentf2e703f9a3caa91e4f3f0a8f5d3fe92dbea05623 (diff)
f2fs: Add the 'whint_mode' mount option to f2fs documentation
Signed-off-by: Hyunchul Lee <cheol.lee@lge.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> [Jaegeuk Kim: Add the write-hint policy in f2fs doc.] Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/f2fs.txt66
1 files changed, 66 insertions, 0 deletions
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index 13c2ff034348..0caf7da0a532 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -174,6 +174,12 @@ offgrpjquota Turn off group journelled quota.
offprjjquota Turn off project journelled quota.
quota Enable plain user disk quota accounting.
noquota Disable all plain disk quota option.
+whint_mode=%s Control which write hints are passed down to block
+ layer. This supports "off", "user-based", and
+ "fs-based". In "off" mode (default), f2fs does not pass
+ down hints. In "user-based" mode, f2fs tries to pass
+ down hints given by users. And in "fs-based" mode, f2fs
+ passes down hints with its policy.
================================================================================
DEBUGFS ENTRIES
@@ -611,3 +617,63 @@ algorithm.
In order to identify whether the data in the victim segment are valid or not,
F2FS manages a bitmap. Each bit represents the validity of a block, and the
bitmap is composed of a bit stream covering whole blocks in main area.
+
+Write-hint Policy
+-----------------
+
+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