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authorYang Shi <yang.shi@linux.alibaba.com>2018-06-19 07:59:18 +0800
committerJonathan Corbet <corbet@lwn.net>2018-06-26 09:01:35 -0600
commitfc1ca3d5b4b9532fff76fa21f7d22efdf02d38b7 (patch)
treeb964cc39500e4f5b4279e28f8df03fdfefa27148 /Documentation/sysctl
parent83d4fcb3a0b36aafb0c9c1c625782a9db561f339 (diff)
downloadlinux-fc1ca3d5b4b9532fff76fa21f7d22efdf02d38b7.tar.bz2
doc: add description to dirtytime_expire_seconds
commit 1efff914afac8a965ad63817ecf8861a927c2ace ("fs: add dirtytime_expire_seconds sysctl") introduced dirtytime_expire_seconds knob, but there is not description about it in Documentation/sysctl/vm.txt. Add the description for it. Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/sysctl')
-rw-r--r--Documentation/sysctl/vm.txt13
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 697ef8c225df..960e82759ffb 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -27,6 +27,7 @@ Currently, these files are in /proc/sys/vm:
- dirty_bytes
- dirty_expire_centisecs
- dirty_ratio
+- dirtytime_expire_seconds
- dirty_writeback_centisecs
- drop_caches
- extfrag_threshold
@@ -178,6 +179,18 @@ The total available memory is not equal to total system memory.
==============================================================
+dirtytime_expire_seconds
+
+When a lazytime inode is constantly having its pages dirtied, the inode with
+an updated timestamp will never get chance to be written out. And, if the
+only thing that has happened on the file system is a dirtytime inode caused
+by an atime update, a worker will be scheduled to make sure that inode
+eventually gets pushed out to disk. This tunable is used to define when dirty
+inode is old enough to be eligible for writeback by the kernel flusher threads.
+And, it is also used as the interval to wakeup dirtytime_writeback thread.
+
+==============================================================
+
dirty_writeback_centisecs
The kernel flusher threads will periodically wake up and write `old' data