Hello,
 I tried to set memory limits for VE to 12G, but my VE is reporting 
something like this:

             total       used       free     shared    buffers     cached
Mem:       7271856    6651672     620184          0          0          0
-/+ buffers/cache:    6651672     620184
Swap:            0          0          0

vzmemcheck says:
veid        LowMem  LowMem     RAM MemSwap MemSwap   Alloc   Alloc   Alloc
              util  commit    util    util  commit    util  commit   limit
2080          2.33   52.50   34.13   30.92   50.71   50.55   50.71   78.80
...

and config looks like this:
..
VMGUARPAGES="1060277:9223372036854775807"
# Secondary parameters
KMEMSIZE="1241063424:1365169766"
TCPSNDBUF="289587200:413687808"
TCPRCVBUF="289587200:413687808"
OTHERSOCKBUF="144793600:268894208"
DGRAMRCVBUF="144793600:144793600"
OOMGUARPAGES="1060277:9223372036854775807"
PRIVVMPAGES="1817964:1999760"
...

i tried increasing KMEMSIZE:
# vzctl set 2080 --kmemsize 449835008:682584883 --save
# vzctl set 2080 --kmemsize 2082126848:2130339532 --save
and even vmguarpages:
# vzctl set 2080 --vmguarpages 1617964:9223372036854775807 --save

but this doesn't change reported available memory... 

-- 
Key fingerprint = 40D0 9FFB 9939 7320 8294  05E0 BCC7 02C4 75CC 50D9
 Total Existance Failure