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/fs/fscache/Kconfig b/fs/fscache/Kconfig
index 7c7bccd..9bbb8ce 100644
--- a/fs/fscache/Kconfig
+++ b/fs/fscache/Kconfig
@@ -11,6 +11,40 @@
See Documentation/filesystems/caching/fscache.txt for more information.
+config FSCACHE_STATS
+ bool "Gather statistical information on local caching"
+ depends on FSCACHE && PROC_FS
+ help
+ This option causes statistical information to be gathered on local
+ caching and exported through file:
+
+ /proc/fs/fscache/stats
+
+ The gathering of statistics adds a certain amount of overhead to
+ execution as there are a quite a few stats gathered, and on a
+ multi-CPU system these may be on cachelines that keep bouncing
+ between CPUs. On the other hand, the stats are very useful for
+ debugging purposes. Saying 'Y' here is recommended.
+
+ See Documentation/filesystems/caching/fscache.txt for more information.
+
+config FSCACHE_HISTOGRAM
+ bool "Gather latency information on local caching"
+ depends on FSCACHE && PROC_FS
+ help
+ This option causes latency information to be gathered on local
+ caching and exported through file:
+
+ /proc/fs/fscache/histogram
+
+ The generation of this histogram adds a certain amount of overhead to
+ execution as there are a number of points at which data is gathered,
+ and on a multi-CPU system these may be on cachelines that keep
+ bouncing between CPUs. On the other hand, the histogram may be
+ useful for debugging purposes. Saying 'N' here is recommended.
+
+ See Documentation/filesystems/caching/fscache.txt for more information.
+
config FSCACHE_DEBUG
bool "Debug FS-Cache"
depends on FSCACHE