Can some one explain me why there is difference in available memory on Guests with same configuration:
Hypervisor:xen 4.2 64 bit
VM1: Centos 5.7 with 2.6.18-274.el5xen,
Assigned memory from xen is exactly same as memory inside guest 524288k (512m)
free -k total used free shared buffers cached Mem: 524288 445004 79284 0 18040 182652 -/+ buffers/cache: 244312 279976 Swap: 524280 0 524280
" Memory: 500984k/524288k available (2533k kernel code, 23212k reserved, 1746k data, 196k init) "
here Why free showed exact memory,where dmesg clear showed 2.5mb for kernel code and 23mb as reserved.
VM2: redhat6.0 with 2.6.32
free -k total used free shared buffers cached 502224 122064 380160 0 7636 32648
For same resources RHEl6.0 with pvopskernel is showing 502224k.
What could be the reason for this behavior can this has something to do with with pvops kernel(linux-kernel with xen support)