Originally posted by: SystemAdmin

Trouble allocating large page for 80% of memory for a p5-575 running AIX 5.3 ML4

We are running AIX 5.3 ML4 on p5-575 with 16GB (15552MB after LPAR) of memory with a HPS switch and we current have 32 16MB pages allocated for the HPS switch adapter. But, when we are trying to allocate large pages to 80% of 15552MB or about 777 16MB pages then AIX 5.3 will only allocate 328 16MB pages or 7200MB and will then generate the following error:

root>vmstat -l
System Configuration: lcpu=8 mem=15552MB
kthr memory page faults cpu large-page

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r b avm fre re pi po fr sr cy in sy cs us sy id wa alp flp
1 1 708892 3249804 0 0 0 0 0 0 1 939 308 0 0 99 0 31 1

root>vmo -o lgpg_regions=777 -o lgpg_size=16777216
vmo: 1485-124 Error setting lgpg_sizelgpg_regions: Not enough space

root>vmstat -l

System Configuration: lcpu=8 mem=15552MB

kthr memory page faults cpu large-page

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r b avm fre re pi po fr sr cy in sy cs us sy id wa alp flp
1 1 708889 2037307 0 0 0 0 0 0 1 942 308 0 0 99 0 31 297

NOTE:(31+297)*16MB=5248MB or 33.7%

root> errpt -a | more

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LABEL: DR_DMA_MAPPER_FAIL
IDENTIFIER: 268DA6A3

Date/Time: Thu Mar 2 09:57:21 2006
Sequence Number: 8940
Machine Id: 00C5EC8B4C00
Node Id: champ02
Class: S
Type: TEMP
Resource Name: DR_KER_MEM

Description
Memory related DR operation failed

Probable Causes
DMA Mapper DR handler failure

Failure Causes
DMA specific memory mapper failed

Recommended Actions
Try DR operation on other memory resources

Detail Data
Return Code
1 -1
Memory Address
0000 0000 0600 0000
Handler Address
0000 0000 03EC FFF8
Module Name

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David Carver (512) 475-9420 dcarver@tacc.utexas.edu
The University of Texas at Austin

#AIX-Forum

Originally posted by: eJones

Pretty quiet here..
not many using large pages yet, I guess?

Could this be related to IY82211 perhaps?
(PARTIAL SUCCESS WHEN DYNAMICALLY RESIZING LARGE PAGE REGIONS)

"Neither the vmo nor the large page portions of the AIX
documentation indicates that an attempt to dynamically
resize the number of large page regions on a system
can partially succeed. In the case of partial success,
an error message is output to the screen indicating
that there is not sufficient memory to fulfill the
request, but a subset of the large page regions may be
allocated."

Perhaps your first command failed, but allocated X amount of pages.
A second attempt using the same command would no longer be possible..?

Eric
#AIX-Forum

Originally posted by: SystemAdmin

But what is causing the "DR_DMA_MAPPER_FAIL" running AIX 5.3 on a Power5?

I have been on Power4 p690s running AIX 5.1/5.2 to allocate 80% of real memory. Now I am only able to allocate about half of real memory running AIX 5.3 on a Power5 and the only error message in errpt is the "DR_DMA_MAPPER_FAIL".

What is restricting AIX 5.3 from allocating more 16MB pages?

Are any other AIX 5.3 sites having the same problem with large pages?
#AIX-Forum