1 files changed, 134 insertions, 0 deletions

diff --git a/fs/cachefiles/proc.c b/fs/cachefiles/proc.c
new file mode 100644
index 000000000000..eccd33941199
--- /dev/null
+++ b/fs/cachefiles/proc.c
@@ -0,0 +1,134 @@
+/* CacheFiles statistics
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include "internal.h"
+
+atomic_t cachefiles_lookup_histogram[HZ];
+atomic_t cachefiles_mkdir_histogram[HZ];
+atomic_t cachefiles_create_histogram[HZ];
+
+/*
+ * display the latency histogram
+ */
+static int cachefiles_histogram_show(struct seq_file *m, void *v)
+{
+        unsigned long index;
+        unsigned x, y, z, t;
+
+        switch ((unsigned long) v) {
+        case 1:
+                seq_puts(m, "JIFS  SECS  LOOKUPS   MKDIRS    CREATES\n");
+                return 0;
+        case 2:
+                seq_puts(m, "===== ===== ========= ========= =========\n");
+                return 0;
+        default:
+                index = (unsigned long) v - 3;
+                x = atomic_read(&cachefiles_lookup_histogram[index]);
+                y = atomic_read(&cachefiles_mkdir_histogram[index]);
+                z = atomic_read(&cachefiles_create_histogram[index]);
+                if (x == 0 && y == 0 && z == 0)
+                        return 0;
+
+                t = (index * 1000) / HZ;
+
+                seq_printf(m, "%4lu  0.%03u %9u %9u %9u\n", index, t, x, y, z);
+                return 0;
+        }
+}
+
+/*
+ * set up the iterator to start reading from the first line
+ */
+static void *cachefiles_histogram_start(struct seq_file *m, loff_t *_pos)
+{
+        if ((unsigned long long)*_pos >= HZ + 2)
+                return NULL;
+        if (*_pos == 0)
+                *_pos = 1;
+        return (void *)(unsigned long) *_pos;
+}
+
+/*
+ * move to the next line
+ */
+static void *cachefiles_histogram_next(struct seq_file *m, void *v, loff_t *pos)
+{
+        (*pos)++;
+        return (unsigned long long)*pos > HZ + 2 ?
+                NULL : (void *)(unsigned long) *pos;
+}
+
+/*
+ * clean up after reading
+ */
+static void cachefiles_histogram_stop(struct seq_file *m, void *v)
+{
+}
+
+static const struct seq_operations cachefiles_histogram_ops = {
+        .start          = cachefiles_histogram_start,
+        .stop           = cachefiles_histogram_stop,
+        .next           = cachefiles_histogram_next,
+        .show           = cachefiles_histogram_show,
+};
+
+/*
+ * open "/proc/fs/cachefiles/XXX" which provide statistics summaries
+ */
+static int cachefiles_histogram_open(struct inode *inode, struct file *file)
+{
+        return seq_open(file, &cachefiles_histogram_ops);
+}
+
+static const struct file_operations cachefiles_histogram_fops = {
+        .owner          = THIS_MODULE,
+        .open           = cachefiles_histogram_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = seq_release,
+};
+
+/*
+ * initialise the /proc/fs/cachefiles/ directory
+ */
+int __init cachefiles_proc_init(void)
+{
+        _enter("");
+
+        if (!proc_mkdir("fs/cachefiles", NULL))
+                goto error_dir;
+
+        if (!proc_create("fs/cachefiles/histogram", S_IFREG | 0444, NULL,
+                         &cachefiles_histogram_fops))
+                goto error_histogram;
+
+        _leave(" = 0");
+        return 0;
+
+error_histogram:
+        remove_proc_entry("fs/cachefiles", NULL);
+error_dir:
+        _leave(" = -ENOMEM");
+        return -ENOMEM;
+}
+
+/*
+ * clean up the /proc/fs/cachefiles/ directory
+ */
+void cachefiles_proc_cleanup(void)
+{
+        remove_proc_entry("fs/cachefiles/histogram", NULL);
+        remove_proc_entry("fs/cachefiles", NULL);
+}