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authorMikulas Patocka <mpatocka@redhat.com>2021-07-27 16:42:21 +0300
committerMike Snitzer <snitzer@redhat.com>2021-08-10 20:27:49 +0300
commite3a35d03407cb3ef9488835aa861e07b45638d0b (patch)
treee008bfff0fa621966fd14270e7c083a87c8bd362 /Documentation/admin-guide/device-mapper
parentdf699cc16ea5ef93a917676dcdd4376e02860ad5 (diff)
downloadlinux-e3a35d03407cb3ef9488835aa861e07b45638d0b.tar.xz
dm writecache: add event counters
Add 10 counters for various events (hit, miss, etc) and export them in the status line (accessed from userspace with "dmsetup status"). Also add a message "clear_stats" that resets these counters. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'Documentation/admin-guide/device-mapper')
-rw-r--r--Documentation/admin-guide/device-mapper/writecache.rst16
1 files changed, 14 insertions, 2 deletions
diff --git a/Documentation/admin-guide/device-mapper/writecache.rst b/Documentation/admin-guide/device-mapper/writecache.rst
index 65427d8dfca6..10429779a91a 100644
--- a/Documentation/admin-guide/device-mapper/writecache.rst
+++ b/Documentation/admin-guide/device-mapper/writecache.rst
@@ -78,13 +78,23 @@ Status:
2. the number of blocks
3. the number of free blocks
4. the number of blocks under writeback
+5. the number of read requests
+6. the number of read requests that hit the cache
+7. the number of write requests
+8. the number of write requests that hit uncommitted block
+9. the number of write requests that hit committed block
+10. the number of write requests that bypass the cache
+11. the number of write requests that are allocated in the cache
+12. the number of write requests that are blocked on the freelist
+13. the number of flush requests
+14. the number of discard requests
Messages:
flush
- flush the cache device. The message returns successfully
+ Flush the cache device. The message returns successfully
if the cache device was flushed without an error
flush_on_suspend
- flush the cache device on next suspend. Use this message
+ Flush the cache device on next suspend. Use this message
when you are going to remove the cache device. The proper
sequence for removing the cache device is:
@@ -98,3 +108,5 @@ Messages:
6. the cache device is now inactive and it can be deleted
cleaner
See above "cleaner" constructor documentation.
+ clear_stats
+ Clear the statistics that are reported on the status line