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authorDavid Howells <dhowells@redhat.com>2009-04-03 11:42:37 -0400
committerDavid Howells <dhowells@redhat.com>2009-04-03 11:42:37 -0400
commit7394daa8c61dfda4baa687f133748fa0b599b017 (patch)
tree32d2c55ed60596918ec62ce6ecca186337bf4660 /Documentation/filesystems/caching
parent06b3db1b9bccdc8c2c743122a89745279e5ecc46 (diff)
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>
Diffstat (limited to 'Documentation/filesystems/caching')
-rw-r--r--Documentation/filesystems/caching/backend-api.txt6
-rw-r--r--Documentation/filesystems/caching/fscache.txt12
2 files changed, 5 insertions, 13 deletions
diff --git a/Documentation/filesystems/caching/backend-api.txt b/Documentation/filesystems/caching/backend-api.txt
index 17723053aa91..382d52cdaf2d 100644
--- a/Documentation/filesystems/caching/backend-api.txt
+++ b/Documentation/filesystems/caching/backend-api.txt
@@ -100,12 +100,6 @@ A sysfs directory called /sys/fs/fscache/<cachetag>/ is created if CONFIG_SYSFS
100is enabled. This is accessible through the kobject struct fscache_cache::kobj 100is enabled. This is accessible through the kobject struct fscache_cache::kobj
101and is for use by the cache as it sees fit. 101and is for use by the cache as it sees fit.
102 102
103The cache driver may create itself a directory named for the cache type in the
104/proc/fs/fscache/ directory. This is available if CONFIG_FSCACHE_PROC is
105enabled and is accessible through:
106
107 struct proc_dir_entry *proc_fscache;
108
109 103
110======================== 104========================
111RELEVANT DATA STRUCTURES 105RELEVANT DATA STRUCTURES
diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt
index a759d916273e..0a751f3c2c70 100644
--- a/Documentation/filesystems/caching/fscache.txt
+++ b/Documentation/filesystems/caching/fscache.txt
@@ -195,7 +195,6 @@ STATISTICAL INFORMATION
195 195
196If FS-Cache is compiled with the following options enabled: 196If FS-Cache is compiled with the following options enabled:
197 197
198 CONFIG_FSCACHE_PROC=y (implied by the following two)
199 CONFIG_FSCACHE_STATS=y 198 CONFIG_FSCACHE_STATS=y
200 CONFIG_FSCACHE_HISTOGRAM=y 199 CONFIG_FSCACHE_HISTOGRAM=y
201 200
@@ -275,7 +274,7 @@ proc files.
275 (*) /proc/fs/fscache/histogram 274 (*) /proc/fs/fscache/histogram
276 275
277 cat /proc/fs/fscache/histogram 276 cat /proc/fs/fscache/histogram
278 +HZ +TIME OBJ INST OP RUNS OBJ RUNS RETRV DLY RETRIEVLS 277 JIFS SECS OBJ INST OP RUNS OBJ RUNS RETRV DLY RETRIEVLS
279 ===== ===== ========= ========= ========= ========= ========= 278 ===== ===== ========= ========= ========= ========= =========
280 279
281 This shows the breakdown of the number of times each amount of time 280 This shows the breakdown of the number of times each amount of time
@@ -291,16 +290,16 @@ proc files.
291 RETRIEVLS Time between beginning and end of a retrieval 290 RETRIEVLS Time between beginning and end of a retrieval
292 291
293 Each row shows the number of events that took a particular range of times. 292 Each row shows the number of events that took a particular range of times.
294 Each step is 1 jiffy in size. The +HZ column indicates the particular 293 Each step is 1 jiffy in size. The JIFS column indicates the particular
295 jiffy range covered, and the +TIME field the equivalent number of seconds. 294 jiffy range covered, and the SECS field the equivalent number of seconds.
296 295
297 296
298========= 297=========
299DEBUGGING 298DEBUGGING
300========= 299=========
301 300
302The FS-Cache facility can have runtime debugging enabled by adjusting the value 301If CONFIG_FSCACHE_DEBUG is enabled, the FS-Cache facility can have runtime
303in: 302debugging enabled by adjusting the value in:
304 303
305 /sys/module/fscache/parameters/debug 304 /sys/module/fscache/parameters/debug
306 305
@@ -327,4 +326,3 @@ the control file. For example:
327 echo $((1|8|64)) >/sys/module/fscache/parameters/debug 326 echo $((1|8|64)) >/sys/module/fscache/parameters/debug
328 327
329will turn on all function entry debugging. 328will turn on all function entry debugging.
330