CentOS - Jul 2008 - 2.6.18-92.1.6.el5xen -- 8GB missing?

Hello,

Last night I upgraded a server to CentOS 5.2.  The server has 16GB of
RAM.  Now that it's running 2.6.18-92.1.6.el5xen only 8GB is reported to
exist.

# cat /proc/meminfo
MemTotal:      8818688 kB
MemFree:       3730124 kB
Buffers:        202004 kB
Cached:        4086788 kB
SwapCached:          0 kB
Active:        1551480 kB
Inactive:      2958196 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:      8818688 kB
LowFree:       3730124 kB
SwapTotal:     8388600 kB
SwapFree:      8388600 kB
Dirty:            7348 kB
Writeback:           0 kB
AnonPages:      220788 kB
Mapped:          46948 kB
Slab:           137404 kB
PageTables:      29012 kB
NFS_Unstable:        0 kB
Bounce:              0 kB
CommitLimit:  12797944 kB
Committed_AS:   756072 kB
VmallocTotal: 34359738367 kB
VmallocUsed:      5004 kB
VmallocChunk: 34359733235 kB

However, dmesg appears to report something else:

# dmesg | grep Memory
Memory: 15506152k/15899468k available (2417k kernel code, 384480k
reserved, 1350k data, 176k init)

I looked in the messages file for complaints and didn't see anything
that strikes me as unusual.

How much memory is available?  Is this a known issue?

On Sat, Jul 12, 2008 at 7:11 PM, JJB <jack at internetguy.net> wrote:
> Hello,
>
> Last night I upgraded a server to CentOS 5.2.  The server has 16GB of
> RAM.  Now that it's running 2.6.18-92.1.6.el5xen only 8GB is reported
to
> exist.
>
> # cat /proc/meminfo
> MemTotal:      8818688 kB
> MemFree:       3730124 kB
> Buffers:        202004 kB
> Cached:        4086788 kB
> SwapCached:          0 kB
> Active:        1551480 kB
> Inactive:      2958196 kB
> HighTotal:           0 kB
> HighFree:            0 kB
> LowTotal:      8818688 kB
> LowFree:       3730124 kB
> SwapTotal:     8388600 kB
> SwapFree:      8388600 kB
> Dirty:            7348 kB
> Writeback:           0 kB
> AnonPages:      220788 kB
> Mapped:          46948 kB
> Slab:           137404 kB
> PageTables:      29012 kB
> NFS_Unstable:        0 kB
> Bounce:              0 kB
> CommitLimit:  12797944 kB
> Committed_AS:   756072 kB
> VmallocTotal: 34359738367 kB
> VmallocUsed:      5004 kB
> VmallocChunk: 34359733235 kB
>
> However, dmesg appears to report something else:
>
> # dmesg | grep Memory
> Memory: 15506152k/15899468k available (2417k kernel code, 384480k
> reserved, 1350k data, 176k init)
>
> I looked in the messages file for complaints and didn't see anything
> that strikes me as unusual.
>
> How much memory is available?  Is this a known issue?
>
>
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos
>
I think there was a topic like this about a month ago, please search the
list archieves.

Cheers.

-- 
"It is human nature to think wisely and act in an absurd fashion."

"Todo el desorden del mundo proviene de las profesiones mal o mediocremente
servidas"
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Victor Padro wrote:
>
>
> On Sat, Jul 12, 2008 at 7:11 PM, JJB <jack at internetguy.net 
> <mailto:jack at internetguy.net>> wrote:
>
>     Hello,
>
>     Last night I upgraded a server to CentOS 5.2.  The server has 16GB of
>     RAM.  Now that it's running 2.6.18-92.1.6.el5xen only 8GB is
>     reported to
>     exist.
>     ...snip...
>
>     How much memory is available?  Is this a known issue?
>
>
> I think there was a topic like this about a month ago, please search 
> the list archieves.
>
> Cheers.
In case he didn't find it, I was the one that posted the original 
issue.  Turns out that Xen allocates memory to domU's and doesn't 
release it back to dom0 even if you stop the VM's.  Top only reports the 
memory available to dom0.  The xen tools will show the proper amount of 
memory. 

Russ