From: kfraser@dhcp93.uk.xensource.com <kfraser@dhcp93.uk.xensource.com>
Date: Wed, 28 Jun 2006 09:32:43 +0000 (+0100)
Subject: [BLKBACK] Output statistics to sysfs.
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~15913^2~4
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=a99e645031f784eda9717fbdf9afccb89162f4c6;p=xen.git

[BLKBACK] Output statistics to sysfs.

The location is 'statistics' directory under each VBD directory, for
example, /sys/devices/xen-backend/vbd-x-xxxx/statistics.

The 'statistics' directory includes the following three statistical
information:
  oo_req
       is the number of requests held up due to full pipeline.
  rd_req
       is the number of processed READ requests.
  wr_req
       is the number of processed WRITE requests.

Signed-off-by: Satoshi UCHIDA <s-uchida@ap.jp.nec.com>
---

diff --git a/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c b/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
index 5ee3a46982..406adf1000 100644
--- a/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
+++ b/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
@@ -43,7 +43,6 @@ static int connect_ring(struct backend_info *);
 static void backend_changed(struct xenbus_watch *, const char **,
 			    unsigned int);
 
-
 static void update_blkif_status(blkif_t *blkif)
 { 
 	int err;
@@ -73,6 +72,70 @@ static void update_blkif_status(blkif_t *blkif)
 }
 
 
+/****************************************************************
+ *  sysfs interface for VBD I/O requests
+ */
+
+#ifdef CONFIG_SYSFS
+
+#define VBD_SHOW(name, format, args...)					\
+	static ssize_t show_##name(struct device *_dev,			\
+				   struct device_attribute *attr,	\
+				   char *buf)				\
+	{								\
+		struct xenbus_device *dev = to_xenbus_device(_dev);	\
+		struct backend_info *be = dev->dev.driver_data;		\
+									\
+		return sprintf(buf, format, ##args);			\
+	}								\
+	DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
+
+VBD_SHOW(oo_req, "%d\n", be->blkif->st_oo_req);
+VBD_SHOW(rd_req, "%d\n", be->blkif->st_rd_req);
+VBD_SHOW(wr_req, "%d\n", be->blkif->st_wr_req);
+
+static struct attribute *vbdstat_attrs[] = {
+	&dev_attr_oo_req.attr,
+	&dev_attr_rd_req.attr,
+	&dev_attr_wr_req.attr,
+	NULL
+};
+
+static struct attribute_group vbdstat_group = {
+	.name = "statistics",
+	.attrs = vbdstat_attrs,
+};
+
+int xenvbd_sysfs_addif(struct xenbus_device *dev)
+{
+	int error = 0;
+	
+	error = sysfs_create_group(&dev->dev.kobj,
+				   &vbdstat_group);
+	if (error)
+		goto fail;
+	
+	return 0;
+	
+fail:
+	sysfs_remove_group(&dev->dev.kobj,
+			   &vbdstat_group);
+	return error;
+}
+
+void xenvbd_sysfs_delif(struct xenbus_device *dev)
+{
+	sysfs_remove_group(&dev->dev.kobj,
+			   &vbdstat_group);
+}
+
+#else
+
+#define xenvbd_sysfs_addif(dev) (0)
+#define xenvbd_sysfs_delif(dev) ((void)0)
+
+#endif /* CONFIG_SYSFS */
+
 static ssize_t show_physical_device(struct device *_dev,
 				    struct device_attribute *attr, char *buf)
 {
@@ -115,6 +178,7 @@ static int blkback_remove(struct xenbus_device *dev)
 
 	device_remove_file(&dev->dev, &dev_attr_physical_device);
 	device_remove_file(&dev->dev, &dev_attr_mode);
+	xenvbd_sysfs_delif(dev);
 
 	kfree(be);
 	dev->dev.driver_data = NULL;
@@ -237,6 +301,7 @@ static void backend_changed(struct xenbus_watch *watch,
 
 		device_create_file(&dev->dev, &dev_attr_physical_device);
 		device_create_file(&dev->dev, &dev_attr_mode);
+		xenvbd_sysfs_addif(dev);
 
 		/* We're potentially connected now */
 		update_blkif_status(be->blkif);