Rework of /proc/stat

Hi,
I've made a new version of IO statistics in kstat that remove the previous limitations of MAX_MAJOR
I've made tests on my machine.
Could someone test it, please?
Feedback welcome.
Bye
-jec

@@ -12,18 +12,37 @@
  * used by rstatd/perfmeter
  */
 
-#define DK_MAX_MAJOR 16
-#define DK_MAX_DISK 16
+#define DK_MAX_DEVICES 64
+#define DK_BUCKETS 256
+
+
+struct _kstat_block_io
+{
+    struct _kstat_block_io* next;
+
+ unsigned int major;
+    unsigned int minor;
+
+ unsigned int io;
+    unsigned int rio;
+    unsigned int wio;
+    unsigned int rblk;
+    unsigned int wblk;
+};
+typedef struct _kstat_block_io kstat_block_io;
+
+
+/* static array of IO stats */
+extern unsigned int kstat_devices_current_index;
+extern kstat_block_io kstat_devices_array[DK_MAX_DEVICES];
+
+
 
 struct kernel_stat {
 	unsigned int per_cpu_user[NR_CPUS],
 	             per_cpu_nice[NR_CPUS],
 	             per_cpu_system[NR_CPUS];
- unsigned int dk_drive[DK_MAX_MAJOR][DK_MAX_DISK];
- unsigned int dk_drive_rio[DK_MAX_MAJOR][DK_MAX_DISK];
- unsigned int dk_drive_wio[DK_MAX_MAJOR][DK_MAX_DISK];
- unsigned int dk_drive_rblk[DK_MAX_MAJOR][DK_MAX_DISK];
- unsigned int dk_drive_wblk[DK_MAX_MAJOR][DK_MAX_DISK];
+    kstat_block_io* io_stat_tbl[DK_BUCKETS];
 	unsigned int pgpgin, pgpgout;
 	unsigned int pswpin, pswpout;
 #if !defined(CONFIG_ARCH_S390)

@@ -37,6 +56,103 @@
 
 extern struct kernel_stat kstat;
 
+
+
+/* Size of the table */
+extern const unsigned int kstat_block_io_tbl_size;
+
+/* hash function */
+static inline unsigned kstat_block_io_hash(unsigned int major, unsigned int minor)
+{
+       return major * 1999 ^ minor;
+}
+
+
+/* add an IO stat */
+static inline kstat_block_io* kstat_block_io_add(unsigned int major, unsigned int minor)
+{
+    unsigned int i;
+ kstat_block_io* p;
+    kstat_block_io* pstat;
+
+ if (kstat_devices_current_index >= DK_MAX_DEVICES)
+ {
+ 
    printk("ERROR: kstat: No more slot for device IO stats. Try 

extending DK_MAX_DEVICES\n");
+

    return 0;

+ }
+
+ pstat = &kstat_devices_array[kstat_devices_current_index];
+ kstat_devices_current_index++;

+    pstat->next = 0;
+    pstat->major = major;
+    pstat->minor = minor;
+    pstat->io = 0;
+    pstat->rio = 0;
+    pstat->wio = 0;
+    pstat->rblk = 0;
+    pstat->wblk = 0;

+
+ i = kstat_block_io_hash(major, minor) % kstat_block_io_tbl_size;
+ p = kstat.io_stat_tbl[i];
+ if (p == 0)
+ {
+

    kstat.io_stat_tbl[i] = pstat;

+ }
+ else
+ {
+
printk("WARNING: kstat: Collision found in IO stat accounting table
(add). Try extending DK_BUCKETS\n");
+ while (p->next != 0)
+

	{
+            p = p->next;
+ 
	}
+ 
    p->next = pstat;

+ }
+ return pstat;
+}
+
+/* lookup an IO stat */
+static inline kstat_block_io* kstat_block_io_lookup(unsigned major, unsigned minor) +{
+ unsigned int i = kstat_block_io_hash(major, minor) % kstat_block_io_tbl_size;
+ kstat_block_io* p = kstat.io_stat_tbl[i];
+ while (p && p->major != major && p->minor != minor)
+ {
+
printk("WARNING: kstat: Collision found in IO stat accounting table
(lookup). Try extending DK_BUCKETS\n");
+

	p = p->next;

+ }
+ if (p == 0)
+ {
+

    p = kstat_block_io_add(major, minor);
+ 
	if (p == 0)
+ 
	{
+ 
	    return 0;
+ 
	}

+ }
+ return p;
+}
+
+/* This is used by MD to see if IDLE */
+static inline unsigned long kstat_get_rwblk(unsigned int major, unsigned int minor) +{
+ kstat_block_io* stat = kstat_block_io_lookup(major, minor);
+ if (stat == 0)
+ {
+

    printk("ERROR: kstat: No IO stat found for (%d/%d)\n", major, minor);

+ return 0;
+ }
+ return stat->rblk + stat->wblk;
+}
+
+
+
+
+
+
+
+
+
+
+
#if !defined(CONFIG_ARCH_S390)
/*
* Number of interrupts per specific IRQ source, since bootup

@@ -3284,6 +3284,9 @@
 	return NULL;
 }
 
+/* MD devices are major=9 and minor=1-31 */
+#define DK_MAX_MAJOR 16
+#define DK_MAX_DISK 32
 static unsigned int sync_io[DK_MAX_MAJOR][DK_MAX_DISK];
 void md_sync_acct(kdev_t dev, unsigned long nr_sectors)
 {

@@ -3305,15 +3308,12 @@
 	unsigned long curr_events;
 
 	idle = 1;
- ITERATE_RDEV(mddev,rdev,tmp) {
+ ITERATE_RDEV(mddev,rdev,tmp)
+ {
 		int major = MAJOR(rdev->dev);
 		int idx = disk_index(rdev->dev);
 
- 

	if ((idx >= DK_MAX_DISK) || (major >= DK_MAX_MAJOR))
- 
		continue;

-
-
curr_events = kstat.dk_drive_rblk[major][idx] +
-

					kstat.dk_drive_wblk[major][idx] ;

+ curr_events = kstat_get_rwblk(major, idx);
curr_events -= sync_io[major][idx]; if ((curr_events - rdev->last_events) > 32) {

	rdev->last_events = curr_events;

@@ -501,19 +501,22 @@
 	 

unsigned long nr_sectors, int new_io)
{
unsigned int major = MAJOR(dev);
- unsigned int index;
+ unsigned int minor = MINOR(dev);
+ kstat_block_io* stat = kstat_block_io_lookup(major, minor);

- index = disk_index(dev);
- if ((index >= DK_MAX_DISK) || (major >= DK_MAX_MAJOR)) -

	return;

+ if (stat == 0)
+ {
+
printk("ERROR: kstat: Haven't found an IO stat struct for major=%d
/ minor=%d\n", major, minor);
+ return;
+ }

- kstat.dk_drive[major][index] += new_io;
+ stat->io += new_io;
if (rw == READ) {
-

	kstat.dk_drive_rio[major][index] += new_io;
- 
	kstat.dk_drive_rblk[major][index] += nr_sectors;
+ 
	stat->rio += new_io;
+ 
	stat->rblk += nr_sectors;
 	} else if (rw == WRITE) {
- 
	kstat.dk_drive_wio[major][index] += new_io;
- 
	kstat.dk_drive_wblk[major][index] += nr_sectors;
+ 
	stat->wio += new_io;
+ 
	stat->wblk += nr_sectors;

} else
printk(KERN_ERR "drive_stat_acct: cmd not R/W?\n");
}

@@ -282,25 +282,19 @@
 		len += sprintf(page + len, " %u", kstat_irqs(i));
 #endif
 
- len += sprintf(page + len, "\ndisk_io: ");
+    len += sprintf(page + len, "\ndisk_io: ");
 
- for (major = 0; major < DK_MAX_MAJOR; major++) {
- 

	for (disk = 0; disk < DK_MAX_DISK; disk++) {

-
int active = kstat.dk_drive[major][disk] +
-
kstat.dk_drive_rblk[major][disk] +
-

			kstat.dk_drive_wblk[major][disk];
- 
		if (active)
- 
			len += sprintf(page + len,
- 
				"(%u,%u):(%u,%u,%u,%u,%u) ",

-
major, disk,
-
kstat.dk_drive[major][disk],
-
kstat.dk_drive_rio[major][disk],
-
kstat.dk_drive_rblk[major][disk],
-
kstat.dk_drive_wio[major][disk],
-
kstat.dk_drive_wblk[major][disk]
-

		);
- 
	}

- }
+ for (i = 0; i < kstat_devices_current_index; i++)
+ {
+ kstat_block_io* stat = &kstat_devices_array[i];
+ len += sprintf( page + len, "(%u,%u):(%u,%u,%u,%u,%u) ",

+                        stat->major, stat->minor,
+                        stat->io,
+                        stat->rio,
+                        stat->wio,
+                        stat->rblk,
+                        stat->wblk );

+ }

len += sprintf(page + len,

"\nctxt %u\n"

Your mailer was hungry and ate the patch (small examples):

...

Russell King ([email protected])                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html

On Wed, Mar 06, 2002 at 06:16:55PM +0100, Jean-Eric Cuendet wrote:
[...]

ScioByte GmbH    Zum Schiersteiner Grund 2     55127 Mainz (Germany)
Phone: +49 700 724 629 83                    Fax: +49 700 724 629 84
1024D/717F16BB    A384 F5F1 F566 5716 5485  27EF 3B00 C007 717F 16BB

Thank for your attention and help on updating my disk io patch. Here is the link to the original patch http://marc.theaimsgroup.com/?l=linux-kernel&m=100570447604813&w=2. I re-submitted it a while ago against 2.4 kernels and 2.5.2 kernel. You
can find patches related to disk io statistics at
http://lse.sourceforge.net/resource/diskio/diskio.html

Thanks, you are right.
I'll change that.
-jec