2.6.25-git19

 mm

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index e8644b1..7c4f9e0 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -4,12 +4,229 @@
 #include <linux/fs.h>
 #include <linux/sched.h>
 #include <linux/module.h>
+#include <linux/writeback.h>
+#include <linux/device.h>
+
+
+static struct class *bdi_class;
+
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+static struct dentry *bdi_debug_root;
+
+static void bdi_debug_init(void)
+{
+   bdi_debug_root = debugfs_create_dir("bdi", NULL);
+}
+
+static int bdi_debug_stats_show(struct seq_file *m, void *v)
+{
+   struct backing_dev_info *bdi = m->private;
+   long background_thresh;
+   long dirty_thresh;
+   long bdi_thresh;
+
+   get_dirty_limits(&background_thresh, &dirty_thresh, &bdi_thresh, bdi);
+
+#define K(x) ((x) << (PAGE_SHIFT - 10))
+   seq_printf(m,
+         "BdiWriteback:     %8lu kB\n"
+         "BdiReclaimable:   %8lu kB\n"
+         "BdiDirtyThresh:   %8lu kB\n"
+         "DirtyThresh:      %8lu kB\n"
+         "BackgroundThresh: %8lu kB\n",
+         (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)),
+         (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)),
+         K(bdi_thresh),
+         K(dirty_thresh),
+         K(background_thresh));
+#undef K
+
+   return 0;
+}
+
+static int bdi_debug_stats_open(struct inode *inode, struct file *file)
+{
+   return single_open(file, bdi_debug_stats_show, inode->i_private);
+}
+
+static const struct file_operations bdi_debug_stats_fops = {
+   .open      = bdi_debug_stats_open,
+   .read      = seq_read,
+   .llseek      = seq_lseek,
+   .release   = single_release,
+};
+
+static void bdi_debug_register(struct backing_dev_info *bdi, const char *name)
+{
+   bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root);
+   bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir,
+                      bdi, &bdi_debug_stats_fops);
+}
+
+static void bdi_debug_unregister(struct backing_dev_info *bdi)
+{
+   debugfs_remove(bdi->debug_stats);
+   debugfs_remove(bdi->debug_dir);
+}
+#else
+static inline void bdi_debug_init(void)
+{
+}
+static inline void bdi_debug_register(struct backing_dev_info *bdi,
+                  const char *name)
+{
+}
+static inline void bdi_debug_unregister(struct backing_dev_info *bdi)
+{
+}
+#endif
+
+static ssize_t read_ahead_kb_store(struct device *dev,
+              struct device_attribute *attr,
+              const char *buf, size_t count)
+{
+   struct backing_dev_info *bdi = dev_get_drvdata(dev);
+   char *end;
+   unsigned long read_ahead_kb;
+   ssize_t ret = -EINVAL;
+
+   read_ahead_kb = simple_strtoul(buf, &end, 10);
+   if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
+      bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10);
+      ret = count;
+   }
+   return ret;
+}
+
+#define K(pages) ((pages) << (PAGE_SHIFT - 10))
+
+#define BDI_SHOW(name, expr)                  \
+static ssize_t name##_show(struct device *dev,            \
+            struct device_attribute *attr, char *page)   \
+{                           \
+   struct backing_dev_info *bdi = dev_get_drvdata(dev);      \
+                           \
+   return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr);   \
+}
+
+BDI_SHOW(read_ahead_kb, K(bdi->ra_pages))
+
+static ssize_t min_ratio_store(struct device *dev,
+      struct device_attribute *attr, const char *buf, size_t count)
+{
+   struct backing_dev_info *bdi = dev_get_drvdata(dev);
+   char *end;
+   unsigned int ratio;
+   ssize_t ret = -EINVAL;
+
+   ratio = simple_strtoul(buf, &end, 10);
+   if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
+      ret = bdi_set_min_ratio(bdi, ratio);
+      if (!ret)
+         ret = count;
+   }
+   return ret;
+}
+BDI_SHOW(min_ratio, bdi->min_ratio)
+
+static ssize_t max_ratio_store(struct device *dev,
+      struct device_attribute *attr, const char *buf, size_t count)
+{
+   struct backing_dev_info *bdi = dev_get_drvdata(dev);
+   char *end;
+   unsigned int ratio;
+   ssize_t ret = -EINVAL;
+
+   ratio = simple_strtoul(buf, &end, 10);
+   if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
+      ret = bdi_set_max_ratio(bdi, ratio);
+      if (!ret)
+         ret = count;
+   }
+   return ret;
+}
+BDI_SHOW(max_ratio, bdi->max_ratio)
+
+#define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store)
+
+static struct device_attribute bdi_dev_attrs[] = {
+   __ATTR_RW(read_ahead_kb),
+   __ATTR_RW(min_ratio),
+   __ATTR_RW(max_ratio),
+   __ATTR_NULL,
+};
+
+static __init int bdi_class_init(void)
+{
+   bdi_class = class_create(THIS_MODULE, "bdi");
+   bdi_class->dev_attrs = bdi_dev_attrs;
+   bdi_debug_init();
+   return 0;
+}
+
+postcore_initcall(bdi_class_init);
+
+int bdi_register(struct backing_dev_info *bdi, struct device *parent,
+      const char *fmt, ...)
+{
+   char *name;
+   va_list args;
+   int ret = 0;
+   struct device *dev;
+
+   va_start(args, fmt);
+   name = kvasprintf(GFP_KERNEL, fmt, args);
+   va_end(args);
+
+   if (!name)
+      return -ENOMEM;
+
+   dev = device_create(bdi_class, parent, MKDEV(0, 0), name);
+   if (IS_ERR(dev)) {
+      ret = PTR_ERR(dev);
+      goto exit;
+   }
+
+   bdi->dev = dev;
+   dev_set_drvdata(bdi->dev, bdi);
+   bdi_debug_register(bdi, name);
+
+exit:
+   kfree(name);
+   return ret;
+}
+EXPORT_SYMBOL(bdi_register);
+
+int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
+{
+   return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev));
+}
+EXPORT_SYMBOL(bdi_register_dev);
+
+void bdi_unregister(struct backing_dev_info *bdi)
+{
+   if (bdi->dev) {
+      bdi_debug_unregister(bdi);
+      device_unregister(bdi->dev);
+      bdi->dev = NULL;
+   }
+}
+EXPORT_SYMBOL(bdi_unregister);
 
 int bdi_init(struct backing_dev_info *bdi)
 {
    int i;
    int err;
 
+   bdi->dev = NULL;
+
+   bdi->min_ratio = 0;
+   bdi->max_ratio = 100;
+   bdi->max_prop_frac = PROP_FRAC_BASE;
+
    for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
       err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0);
       if (err)
@@ -33,6 +250,8 @@ void bdi_destroy(struct backing_dev_info *bdi)
 {
    int i;
 
+   bdi_unregister(bdi);
+
    for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
       percpu_counter_destroy(&bdi->bdi_stat[i]);