FS-Cache: Add use of /proc and presentation of statistics
Make FS-Cache create its /proc interface and present various statistical
information through it. Also provide the functions for updating this
information.
These features are enabled by:
CONFIG_FSCACHE_PROC
CONFIG_FSCACHE_STATS
CONFIG_FSCACHE_HISTOGRAM
The /proc directory for FS-Cache is also exported so that caching modules can
add their own statistics there too.
The FS-Cache module is loadable at this point, and the statistics files can be
examined by userspace:
cat /proc/fs/fscache/stats
cat /proc/fs/fscache/histogram
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt
index a759d91..0a751f3 100644
--- a/Documentation/filesystems/caching/fscache.txt
+++ b/Documentation/filesystems/caching/fscache.txt
@@ -195,7 +195,6 @@
If FS-Cache is compiled with the following options enabled:
- CONFIG_FSCACHE_PROC=y (implied by the following two)
CONFIG_FSCACHE_STATS=y
CONFIG_FSCACHE_HISTOGRAM=y
@@ -275,7 +274,7 @@
(*) /proc/fs/fscache/histogram
cat /proc/fs/fscache/histogram
- +HZ +TIME OBJ INST OP RUNS OBJ RUNS RETRV DLY RETRIEVLS
+ JIFS SECS OBJ INST OP RUNS OBJ RUNS RETRV DLY RETRIEVLS
===== ===== ========= ========= ========= ========= =========
This shows the breakdown of the number of times each amount of time
@@ -291,16 +290,16 @@
RETRIEVLS Time between beginning and end of a retrieval
Each row shows the number of events that took a particular range of times.
- Each step is 1 jiffy in size. The +HZ column indicates the particular
- jiffy range covered, and the +TIME field the equivalent number of seconds.
+ Each step is 1 jiffy in size. The JIFS column indicates the particular
+ jiffy range covered, and the SECS field the equivalent number of seconds.
=========
DEBUGGING
=========
-The FS-Cache facility can have runtime debugging enabled by adjusting the value
-in:
+If CONFIG_FSCACHE_DEBUG is enabled, the FS-Cache facility can have runtime
+debugging enabled by adjusting the value in:
/sys/module/fscache/parameters/debug
@@ -327,4 +326,3 @@
echo $((1|8|64)) >/sys/module/fscache/parameters/debug
will turn on all function entry debugging.
-