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solaris:balloon.4d

balloon


NAME

balloon - memory ballooning driver

SYNOPSIS

/platform/i86hvm/kernel/drv/amd64/balloon

DESCRIPTION

The balloon driver is used to adjust current memory reservation for Solaris domU that is running on Xen hypervisor.

Xen dom0 controls the balloon module running within Solaris guest, directing it to allocate guest pages and pin them in “physical” memory. The machine pages backing this memory can then be reclaimed by Xen dom0. Inflating the balloon increases memory pressure, forcing Oracle Solaris to invoke its own memory management algorithms. Oracle Solaris may page out to its virtual disk when memory is scarce. Deflating the balloon decreases pressure, freeing guest memory.

EXAMPLES

Example 1 Inflate and deflate memory balloon driver.

Inflate memory balloon driver in domU (ID 27), which was assigned 4096MB memory at domain creation.

[In dom0]
#xm mem-set 27 2048
#xm list
Name ID Mem VCPUs State Time(s)
Domain-0 0 1798 16 r—– 74838.9
domU 27 2048 2 -b—- 416.8

[In domU]
#echo “::memstat” | mdb -k
Page Summary Pages MB %Tot
———— —————- —————- —-
Kernel 143185 559 14%
ZFS File Data 2720 10 0%
Anon 31720 123 3%
Exec and libs 1524 5 0%
Page cache 5284 20 1%
Free (cachelist) 3207 12 0%
Free (freelist) 333575 1303 32%
Balloon 524191 2047 50%

Total 1045406 4083
Physical 1045405 4083

Deflate memory balloon driver in domU (ID 27).

[In dom0]
#xm mem-set 27 4096
#xm list
Name ID Mem VCPUs State Time(s)
Domain-0 0 1798 16 r—– 74842.8
domU 27 4096 2 r—– 421.2

[In domU]
#echo “::memstat” | mdb -k
Page Summary Pages MB %Tot
———— —————- —————- —-
Kernel 143190 559 14%
ZFS File Data 2752 10 0%
Anon 31721 123 3%
Exec and libs 1525 5 0%
Page cache 5208 20 0%
Free (cachelist) 3283 12 0%
Free (freelist) 857727 3350 82%
Balloon 0 0 0%

Total 1045406 4083
Physical 1045405 4083

Currently, the balloon driver only supports adjusting memory reservation within the maximum memory size assigned at domU creation. It is (0,4096] in the above example.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:

SEE ALSO

solaris/balloon.4d.txt · Last modified: 2023/07/19 08:58 by A User Not Logged in