mm: cleancache: report statistics via debugfs instead of sysfs.

[v9: akpm@linux-foundation.org: sysfs->debugfs; no longer need Doc/ABI file]

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Jan Beulich <JBeulich@novell.com>
Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Rik Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>

diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-cleancache b/Documentation/ABI/testing/sysfs-kernel-mm-cleancache
deleted file mode 100644 (file)
index 662ae64..0000000
--- a/Documentation/ABI/testing/sysfs-kernel-mm-cleancache
+++ /dev/null
@@ -1,11 +0,0 @@
-What:          /sys/kernel/mm/cleancache/
-Date:          April 2011
-Contact:       Dan Magenheimer <dan.magenheimer@oracle.com>
-Description:
-               /sys/kernel/mm/cleancache/ contains a number of files which
-               record a count of various cleancache operations
-               (sum across all filesystems):
-                       succ_gets
-                       failed_gets
-                       puts
-                       flushes

diff --git a/Documentation/vm/cleancache.txt b/Documentation/vm/cleancache.txt
index e0a535677b7b70d7075f7f5aa1347e789a907cfc..f726717ace6b5cdb20e982a08731423629b65eb3 100644 (file)
--- a/Documentation/vm/cleancache.txt
+++ b/Documentation/vm/cleancache.txt
@@ -84,8 +84,8 @@ lock the page to ensure serial behavior.
 
 CLEANCACHE PERFORMANCE METRICS
 
-Cleancache monitoring is done by sysfs files in the
-/sys/kernel/mm/cleancache directory.  The effectiveness of cleancache
+If properly configured, monitoring of cleancache is done via debugfs in
+the /sys/kernel/debug/mm/cleancache directory.  The effectiveness of cleancache
 can be measured (across all filesystems) with:
 
 succ_gets      - number of gets that were successful

diff --git a/mm/cleancache.c b/mm/cleancache.c
index b9c198bc6980235e087a95288fc00d927872759e..deb9f2c06fb7593050ad0d263c46579449da47bc 100644 (file)
--- a/mm/cleancache.c
+++ b/mm/cleancache.c
@@ -15,6 +15,7 @@
 #include <linux/fs.h>
 #include <linux/exportfs.h>
 #include <linux/mm.h>
+#include <linux/debugfs.h>
 #include <linux/cleancache.h>
 
 /*
@@ -33,11 +34,15 @@ EXPORT_SYMBOL(cleancache_enabled);
  */
 static struct cleancache_ops cleancache_ops;
 
-/* useful stats available in /sys/kernel/mm/cleancache */
-static unsigned long cleancache_succ_gets;
-static unsigned long cleancache_failed_gets;
-static unsigned long cleancache_puts;
-static unsigned long cleancache_flushes;
+/*
+ * Counters available via /sys/kernel/debug/frontswap (if debugfs is
+ * properly configured.  These are for information only so are not protected
+ * against increment races.
+ */
+static u64 cleancache_succ_gets;
+static u64 cleancache_failed_gets;
+static u64 cleancache_puts;
+static u64 cleancache_invalidates;
 
 /*
  * register operations for cleancache, returning previous thus allowing
@@ -163,7 +168,7 @@ void __cleancache_invalidate_page(struct address_space *mapping,
                if (cleancache_get_key(mapping->host, &key) >= 0) {
                        (*cleancache_ops.invalidate_page)(pool_id,
                                                          key, page->index);
-                       cleancache_flushes++;
+                       cleancache_invalidates++;
                }
        }
 }
@@ -199,48 +204,19 @@ void __cleancache_invalidate_fs(struct super_block *sb)
 }
 EXPORT_SYMBOL(__cleancache_invalidate_fs);
 
-#ifdef CONFIG_SYSFS
-
-/* see Documentation/ABI/xxx/sysfs-kernel-mm-cleancache */
-
-#define CLEANCACHE_SYSFS_RO(_name) \
-       static ssize_t cleancache_##_name##_show(struct kobject *kobj, \
-                               struct kobj_attribute *attr, char *buf) \
-       { \
-               return sprintf(buf, "%lu\n", cleancache_##_name); \
-       } \
-       static struct kobj_attribute cleancache_##_name##_attr = { \
-               .attr = { .name = __stringify(_name), .mode = 0444 }, \
-               .show = cleancache_##_name##_show, \
-       }
-
-CLEANCACHE_SYSFS_RO(succ_gets);
-CLEANCACHE_SYSFS_RO(failed_gets);
-CLEANCACHE_SYSFS_RO(puts);
-CLEANCACHE_SYSFS_RO(flushes);
-
-static struct attribute *cleancache_attrs[] = {
-       &cleancache_succ_gets_attr.attr,
-       &cleancache_failed_gets_attr.attr,
-       &cleancache_puts_attr.attr,
-       &cleancache_flushes_attr.attr,
-       NULL,
-};
-
-static struct attribute_group cleancache_attr_group = {
-       .attrs = cleancache_attrs,
-       .name = "cleancache",
-};
-
-#endif /* CONFIG_SYSFS */
-
 static int __init init_cleancache(void)
 {
-#ifdef CONFIG_SYSFS
-       int err;
-
-       err = sysfs_create_group(mm_kobj, &cleancache_attr_group);
-#endif /* CONFIG_SYSFS */
+#ifdef CONFIG_DEBUG_FS
+       struct dentry *root = debugfs_create_dir("cleancache", NULL);
+       if (root == NULL)
+               return -ENXIO;
+       debugfs_create_u64("succ_gets", S_IRUGO, root, &cleancache_succ_gets);
+       debugfs_create_u64("failed_gets", S_IRUGO,
+                               root, &cleancache_failed_gets);
+       debugfs_create_u64("puts", S_IRUGO, root, &cleancache_puts);
+       debugfs_create_u64("invalidates", S_IRUGO,
+                               root, &cleancache_invalidates);
+#endif
        return 0;
 }
 module_init(init_cleancache)