From fc1ca3d5b4b9532fff76fa21f7d22efdf02d38b7 Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Tue, 19 Jun 2018 07:59:18 +0800 Subject: [PATCH] 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 Signed-off-by: Yang Shi Signed-off-by: Jonathan Corbet --- Documentation/sysctl/vm.txt | 13 +++++++++++++ 1 file changed, 13 insertions(+) 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 -- 2.30.2