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What is "hole" in vmstat output?

raulnga
Occasional Visitor

What is "hole" in vmstat output?

Hi,
I am supporting an AphaServer

Virtual Memory Statistics: (pagesize = 8192)
procs memory pages intr cpu
r w u act free wire fault cow zero react pin pout in sy cs us sy id
10 542 54 566K 524K 63K 31M 2M 22M 3604 3M 0 182 3K 3K 12 2 86
8 547 54 566K 524K 63K 1943 1003 3434 0 1150 0 27 4K 1K 9 4 87
8 548 54 566K 524K 63K 1568 312 828 0 340 0 28 5K 2K 7 4 89
19 537 54 566K 524K 63K 12 5 29 0 8 0 140 11K 8K 55 6 39
10 546 54 566K 524K 63K 0 0 0 0 0 0 136 9K 8K 53 5 42
15 541 54 566K 524K 63K 0 0 0 0 0 0 148 9K 9K 51 5 44
11 545 54 566K 524K 63K 0 0 0 0 0 0 135 8K 7K 44 5 51
8 548 54 566K 524K 63K 1 0 0 0 0 0 134 8K 8K 45 5 50
11 545 54 566K 524K 63K 1 0 0 0 0 0 140 7K 7K 40 4 56
14 542 54 566K 524K 63K 0 0 0 0 0 0 131 8K 9K 43 5 52

Total Physical Memory = 9216.00 M
= 1179648 pages

Physical Memory Clusters:

start_pfn end_pfn type size_pages / size_bytes
0 512 pal 512 / 4.00M
512 655341 os 654829 / 5115.85M
655341 655360 pal 19 / 152.00k
8388608 8912872 os 524264 / 4095.81M
8912872 8912896 pal 24 / 192.00k

Physical Memory Use:

start_pfn end_pfn type size_pages / size_bytes
512 1032 scavenge 520 / 4.06M
1032 1861 text 829 / 6.48M
1861 2048 scavenge 187 / 1.46M
2048 2217 data 169 / 1.32M
2217 2451 bss 234 / 1.83M
2451 2654 kdebug 203 / 1.59M
2654 2660 cfgmgmt 6 / 48.00k
2660 2662 locks 2 / 16.00k
2662 2678 pmap 16 / 128.00k
2678 5443 unixtable 2765 / 21.60M
5443 5659 logs 216 / 1.69M
5659 16664 vmtables 11005 / 85.98M
16664 655341 managed 638677 / 4989.66M
*******************************************************
655341 8388608 hole 7733267 / 60416.15M
*******************************************************
8388608 8388609 unixtable 1 / 8.00k
8388609 8388612 pmap 3 / 24.00k
8388612 8389128 scavenge 516 / 4.03M
8389128 8389957 text 829 / 6.48M
8389957 8398003 vmtables 8046 / 62.86M
8398003 8912872 managed 514869 / 4022.41M
============================
Total Physical Memory Use: 1179093 / 9211.66M

Managed Pages Break Down:

free pages = 524293
active pages = 426106
inactive pages = 95128
wired pages = 63562
ubc pages = 45680
==================
Total = 1154769

WIRED Pages Break Down:

vm wired pages = 10411
ubc wired pages = 0
meta data pages = 35307
malloc pages = 11899
contig pages = 2235
user ptepages = 1357
kernel ptepages = 318
free ptepages = 5
==================
Total = 61532


Virtual Memory Statistics: (pagesize = 8192)
426105 active pages
95128 inactive pages
524295 free pages
63562 wired pages
31311359 virtual memory page faults
2794624 copy-on-write page faults
22427849 zero fill page faults
3604 reattaches from reclaim list
3455078 pages paged in
0 pages paged out
1304496861 task and thread context switches
72490705 device interrupts
1353707553 system calls

I don´t know what can this be:
655341 8388608 hole 7733267 / 60416.15M

Thanks,
Ra
1 REPLY
Nigel Halliday
Occasional Advisor

Re: What is "hole" in vmstat output?

What type of AlphaServer do you have?

Wildfire (GSxx) systems have separate RADs (resource affinity domains) each capable of having 64Gb of physical memory installed. It looks like you have 5Gb installed in one QBB (Quad Building Block) and 4Gb installed in another. The OS has to account for the physically installed non-contiguous memory so a hole is created.

Hope this explains it.

Nigel