free -m显示总共有309 Mb的4GB内存的系统

操作系统：Xen云平台1.1（XCP）修改的centos，以及在intel i5上运行的xen server 5.0

免费-m

total used free shared buffers cached Mem: 309 136 172 0 1 17 -/+ buffers/cache: 117 191 Swap: 511 7 504 

df -h

 none 380M 0 380M 0% /dev/shm 

猫/ proc / meminfo

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 MemTotal: 316416 kB MemFree: 79024 kB Buffers: 5444 kB Cached: 79304 kB SwapCached: 0 kB Active: 48020 kB Inactive: 64092 kB Active(anon): 30572 kB Inactive(anon): 1624 kB Active(file): 17448 kB Inactive(file): 62468 kB Unevictable: 6436 kB Mlocked: 6436 kB HighTotal: 0 kB HighFree: 0 kB LowTotal: 316416 kB LowFree: 79024 kB SwapTotal: 524280 kB SwapFree: 524280 kB Dirty: 172 kB Writeback: 0 kB AnonPages: 33876 kB Mapped: 17864 kB Shmem: 124 kB Slab: 17100 kB SReclaimable: 8276 kB SUnreclaim: 8824 kB KernelStack: 1464 kB PageTables: 0 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 682488 kB Committed_AS: 647196 kB VmallocTotal: 245752 kB VmallocUsed: 4576 kB VmallocChunk: 237148 kB DirectMap4k: 754492 kB DirectMap2M: 0 kB** 

顶级输出

 Mem: 316416k total, 237992k used, 78424k free, 5636k buffers Swap: 524280k total, 0k used, 524280k free, 79404k cached 

顶部按ram（shift + m）sorting

 top - 14:59:20 up 29 min, 1 user, load average: 0.00, 0.00, 0.00 Tasks: 113 total, 1 running, 112 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 316416k total, 238008k used, 78408k free, 5708k buffers Swap: 524280k total, 0k used, 524280k free, 79440k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 5942 root 17 -3 179m 12m 5492 S 0.3 4.2 0:05.72 xapi 6964 root 20 0 11776 7672 2856 S 0.3 2.4 0:00.87 python 5939 root 17 -3 21524 6092 2880 S 0.0 1.9 0:00.00 xapi 6700 root 20 0 11768 5028 1644 S 0.0 1.6 0:00.16 python 5740 ntp 20 0 4496 4496 3488 S 0.0 1.4 0:00.05 ntpd 6398 root 20 0 27772 4052 1020 S 0.0 1.3 0:00.01 snapwatchd 5634 root 20 0 170m 3620 2664 S 0.0 1.1 0:00.02 lwregd 5527 root RT 0 3432 3432 2708 S 0.0 1.1 0:00.04 multipathd 7909 root 20 0 10168 2824 2268 S 0.0 0.9 0:00.03 sshd 6128 root 20 0 29608 2792 1540 S 0.0 0.9 0:00.03 mpathalert 7921 root 20 0 5152 2024 1268 S 0.0 0.6 0:00.05 bash 5632 root 20 0 173m 1576 1036 S 0.0 0.5 0:00.00 lwsmd 5241 root 10 -10 5988 1504 928 S 0.0 0.5 0:00.30 ovs-vswitchd 5804 root 20 0 2992 1472 564 S 0.0 0.5 0:00.09 fe 5909 root 20 0 11600 1452 912 S 0.0 0.5 0:00.04 squeezed 5228 root 10 -10 5448 1440 1052 S 0.0 0.5 0:00.08 ovsdb-server 5858 root 20 0 5360 1304 780 S 0.0 0.4 0:00.03 xenstored 5831 root 20 0 12964 1212 756 S 0.0 0.4 0:00.00 v6d 6552 root 20 0 5384 1108 572 S 0.0 0.4 0:00.00 crond 8122 root 20 0 2404 1104 836 R 0.3 0.3 0:00.41 top 6499 root 20 0 7180 1068 664 S 0.0 0.3 0:00.00 sshd 5834 root 20 0 21112 1064 604 S 0.0 0.3 0:00.36 v6d 6968 root 20 0 4492 1044 672 S 0.0 0.3 0:00.00 vncterm 6969 root 20 0 2544 1044 912 S 0.0 0.3 0:00.00 dom0term.sh 5240 root 10 -10 5880 832 272 S 0.0 0.3 0:00.28 ovs-vswitchd 1527 root 16 -4 2364 744 396 S 0.0 0.2 0:01.24 udevd 1 root 20 0 2156 664 564 S 0.0 0.2 0:00.21 init 5563 rpc 20 0 1904 644 548 S 0.0 0.2 0:00.00 portmap 6038 root 17 -3 5208 632 272 S 0.0 0.2 0:00.00 stunnel 5376 root 20 0 1808 616 516 S 0.0 0.2 0:00.01 syslogd 5227 root 10 -10 5444 556 280 S 0.0 0.2 0:00.27 ovsdb-server 5861 root 20 0 10392 548 436 S 0.0 0.2 0:00.00 xenconsoled 5869 root 20 0 3072 476 256 D 0.0 0.2 0:00.51 cdrommon 6967 root 20 0 1752 472 404 S 0.0 0.1 0:00.00 agetty 6965 root 20 0 1740 452 388 S 0.0 0.1 0:00.00 mingetty 

在BIOS 4 GB的安装内存正在显示。在同一台机器早些时候Ubuntu的12.04运行时出现任何内存的问题。

更新：

在xsconsole（xen控制台）>硬件和BIOS信息>系统内存>中

总内存4096 MB

填充内存插槽2

总内存插槽4

 ... label xe # XCP kernel mboot.c32 append /boot/xen.gz dom0_mem=752M lowmem_emergency_pool=1M crashkernel=64M@32M console= vga=mode-0x0311 --- /boot/vmlinuz-2.6-xen root=LABEL=root-nddcwqei ro xencons=hvc console=hvc0 console=tty0 quiet vga=785 splash --- /boot/initrd-2.6-xen.img ...