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-rw-r--r--Documentation/filesystems/f2fs.rst29
1 files changed, 29 insertions, 0 deletions
diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
index efc3493fd6..68a0885fb5 100644
--- a/Documentation/filesystems/f2fs.rst
+++ b/Documentation/filesystems/f2fs.rst
@@ -774,6 +774,35 @@ 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
+-----------------
+
+F2FS sets the whint all the time with the below policy.
+
+===================== ======================== ===================
+User F2FS Block
+===================== ======================== ===================
+N/A META WRITE_LIFE_NONE|REQ_META
+N/A HOT_NODE WRITE_LIFE_NONE
+N/A WARM_NODE WRITE_LIFE_MEDIUM
+N/A COLD_NODE WRITE_LIFE_LONG
+ioctl(COLD) COLD_DATA WRITE_LIFE_EXTREME
+extension list " "
+
+-- buffered io
+N/A COLD_DATA WRITE_LIFE_EXTREME
+N/A HOT_DATA WRITE_LIFE_SHORT
+N/A WARM_DATA WRITE_LIFE_NOT_SET
+
+-- 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
+===================== ======================== ===================
+
Fallocate(2) Policy
-------------------