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| author |   Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2019-02-21 11:49:27 -0500 |
|---|---|---|
| committer |   Theodore Ts'o <tytso@mit.edu> | 2019-02-21 11:49:27 -0500 |
| commit | bc1d69d6151f1911ecb120a8dbd65e47210b7a72 (patch) | |
| tree | 894a447e6f9669653f4668ab3f791534d6b5f460 /Documentation/ABI/testing | |
| parent | ext4: Change debugging support help prefix from EXT4 to Ext4 (diff) | |
| download | linux-dev-bc1d69d6151f1911ecb120a8dbd65e47210b7a72.tar.xz linux-dev-bc1d69d6151f1911ecb120a8dbd65e47210b7a72.zip | |
ext4: add sysfs attr /sys/fs/ext4/<disk>/journal_task
This is useful for moving journal thread into cgroup or
for tracing it with ftrace/perf/blktrace.
For now the only way is `pgrep jbd2/$DISK` but this is not reliable:
name may be longer than "comm" limit and any task could mock it.
Attribute shows pid in current pid-namespace or 0 if task is unreachable.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'Documentation/ABI/testing')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-fs-ext4 | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-fs-ext4 b/Documentation/ABI/testing/sysfs-fs-ext4 index c631253cf85c..78604db56279 100644 --- a/Documentation/ABI/testing/sysfs-fs-ext4 +++ b/Documentation/ABI/testing/sysfs-fs-ext4 @@ -109,3 +109,10 @@ Description: write operation (since a 4k random write might turn into a much larger write due to the zeroout operation). + +What: /sys/fs/ext4/<disk>/journal_task +Date: February 2019 +Contact: "Theodore Ts'o" <tytso@mit.edu> +Description: + This file is read-only and shows the pid of journal thread in + current pid-namespace or 0 if task is unreachable. |