[PATCH] Rework of /proc/stat

From: Jean-Eric Cuendet (jean-eric.cuendet@linkvest.com)
Date: Wed Mar 06 2002 - 12:43:26 EST


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 only, so could someone test it, please?
Feedback welcome.
Bye
-jec

Patch attached.


--- /tmp/linux-2.4.18-vanilla/include/linux/kernel_stat.h Thu Nov 22 20:46:19 2001
+++ /toc/linux-2.4.18-reempt/include/linux/kernel_stat.h Wed Mar 6 18:02:57 2002
@@ -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
--- /tmp/linux-2.4.18-vanilla/drivers/md/md.c Mon Feb 25 20:37:58 2002
+++ /toc/linux-2.4.18-reempt/drivers/md/md.c Wed Mar 6 16:46:56 2002
@@ -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;
--- /tmp/linux-2.4.18-vanilla/drivers/block/ll_rw_blk.c Mon Feb 25 20:37:57 2002
+++ /toc/linux-2.4.18-reempt/drivers/block/ll_rw_blk.c Wed Mar 6 18:12:03 2002
@@ -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");
 }
--- /tmp/linux-2.4.18-vanilla/fs/proc/proc_misc.c Wed Nov 21 06:29:09 2001
+++ /toc/linux-2.4.18-reempt/fs/proc/proc_misc.c Wed Mar 6 17:41:28 2002
@@ -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"

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