Messages in this thread |  | | Date | Wed, 12 Sep 2001 10:51:51 +0100 | From | Sean Hunter <> | Subject | /proc/meminfo swap counter wraparound in 2.2 |
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Hi there
Having put 8Gb of swap on one of our production database servers[1], I found that "top", "free" et al report the amount of available swap space incorrectly.
This is because they all parse /proc/meminfo, and its counters seem to wrap when they encounter very high numbers. The relevant bit is the totalswap member of "struct sysinfo"
sean@lisa:~$ cat /proc/swaps Filename Type Size Used Priority /dev/rd/c0d2p1 partition 530104 41436 10 /usr/SWAPFILE1 file 1048568 56 2 /usr/local/SWAPFILE1 file 1048568 52 2 /usr/SWAPFILE2 file 1572856 0 3 /usr/local/SWAPFILE2 file 1572856 0 3 /var/SWAPFILE2 file 1572856 0 3 /home/SWAPFILE2 file 1572856 0 -6
sean@lisa:~$ cat /proc/meminfo total: used: free: shared: buffers: cached: Mem: 4125683712 2820616192 1305067520 0 82919424 232722432 Swap: 542777344 42541056 500236288 MemTotal: 4028988 kB MemFree: 1274480 kB MemShared: 0 kB Buffers: 80976 kB Cached: 227268 kB BigTotal: 3111908 kB BigFree: 1266988 kB SwapTotal: 530056 kB SwapFree: 488512 kB
sean@lisa:~$ uname -a Linux lisa.sportingbet.com 2.2.19-6.2.7enterprise #1 SMP Thu Jun 14 07:34:12 EDT 2001 i686 unknown
As you can see, we are running redhat's "enterprise" 2.2.19 kernel.
I would be amazed if this bug were not also in the main 2.2.x tree. Is a fix likely or even possible in 2.2 ?
Sean
[1]One of several changes to avoid random oracle 600 errors under heavy load. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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