path: root/block
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authorBen Woodard <woodard@redhat.com>2006-03-22 08:09:31 +0100
committerJens Axboe <axboe@nelson.home.kernel.dk>2006-03-27 09:29:02 +0200
commit837c7878771c15ed8d85ecf814ece7fcb4551b46 (patch)
tree28b06f0734958802ab98e1e6712ac3c6bf8f2518 /block
parent4c5d0bbde9669cfb7f7fd4670dc9a117aea90384 (diff)
[BLOCK] increase size of disk stat counters
The kernel's representation of the disk statistics uses the type unsigned which is 32b on both 32b and 64b platforms. Unfortunately, most system tools that work with these numbers that are exported in /proc/diskstats including iostat read these numbers into unsigned longs. This works fine on 32b platforms and when the number of IO transactions are small on 64b platforms. However, when the numbers wrap on 64b platforms & you read the numbers into unsigned longs, and compare the numbers to previous readings, then you get an unsigned representation of a negative number. This looks like a very large 64b number & gives you bizarre readouts in iostat: ilc4: Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util ilc4: sda 5.50 0.00 143.96 0.00 307496983987862656.00 0.00 153748491993931328.00 0.00 2136028725038430.00 7.94 55.12 5.59 80.42 Though fixing iostat in user space is possible, and a quick survey indicates that several other similar tools also use unsigned longs when processing /proc/diskstats. Therefore, it seems like a better approach would be to extend the length of the disk_stats structure on 64b architectures to 64b. The following patch does that. It should not affect the operation on 32b platforms. Signed-off-by: Ben Woodard <woodard@redhat.com> Cc: Rick Lindsley <ricklind@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'block')
1 files changed, 3 insertions, 3 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 64510fd88621..db4c60c802d6 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -454,8 +454,8 @@ static ssize_t disk_stats_read(struct gendisk * disk, char *page)
return sprintf(page,
- "%8u %8u %8llu %8u "
- "%8u %8u %8llu %8u "
+ "%8lu %8lu %8llu %8u "
+ "%8lu %8lu %8llu %8u "
"%8u %8u %8u"
disk_stat_read(disk, ios[READ]),
@@ -649,7 +649,7 @@ static int diskstats_show(struct seq_file *s, void *v)
- seq_printf(s, "%4d %4d %s %u %u %llu %u %u %u %llu %u %u %u %u\n",
+ seq_printf(s, "%4d %4d %s %lu %lu %llu %u %lu %lu %llu %u %u %u %u\n",
gp->major, n + gp->first_minor, disk_name(gp, n, buf),
disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]),
(unsigned long long)disk_stat_read(gp, sectors[0]),