<div class="gmail_quote">On Thu, May 17, 2012 at 1:58 PM, Michael Coffman <<a href="mailto:michael.coffman@avagotech.com" target="_blank">michael.coffman@avagotech.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div class="gmail_quote">On Thu, May 17, 2012 at 1:26 PM, VINIT ADYA (BLOOMBERG/ 731 LEXIN) <<a href="mailto:vadya@bloomberg.net" target="_blank">vadya@bloomberg.net</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Can you post /proc/meminfo. </blockquote><div> </div></div></blockquote><div> Here is meminfo with overcommit_memory=0 and overcommit_ration=50 (defaults) MemTotal: 2052176 kB MemFree: 1658912 kB Buffers: 23036 kB Cached: 261572 kB SwapCached: 0 kB Active: 94208 kB Inactive: 205604 kB Active(anon): 20732 kB Inactive(anon): 4 kB Active(file): 73476 kB Inactive(file): 205600 kB Unevictable: 6216 kB Mlocked: 6216 kB SwapTotal: 2052088 kB SwapFree: 2052088 kB Dirty: 408 kB Writeback: 0 kB AnonPages: 21456 kB Mapped: 15476 kB Shmem: 224 kB Slab: 43392 kB SReclaimable: 17856 kB SUnreclaim: 25536 kB KernelStack: 1048 kB PageTables: 3292 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 3078176 kB Committed_AS: 137197242528 kB VmallocTotal: 34359738367 kB VmallocUsed: 13156 kB VmallocChunk: 34359715924 kB HardwareCorrupted: 0 kB AnonHugePages: 0 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 6148 kB DirectMap2M: 2088960 kB </div><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="gmail_quote"><div>This is after the system has been rebooted with overcommit turned off. Not sure if that matters: [root@joker ~]# cat /proc/meminfo MemTotal: 2052176 kB MemFree: 1657152 kB Buffers: 20160 kB Cached: 254396 kB SwapCached: 0 kB Active: 126156 kB Inactive: 174860 kB Active(anon): 31988 kB Inactive(anon): 8 kB Active(file): 94168 kB Inactive(file): 174852 kB Unevictable: 6216 kB Mlocked: 6216 kB SwapTotal: 2052088 kB SwapFree: 2052088 kB Dirty: 188 kB Writeback: 0 kB AnonPages: 32588 kB Mapped: 16740 kB Shmem: 228 kB Slab: 43436 kB SReclaimable: 17768 kB SUnreclaim: 25668 kB KernelStack: 1080 kB PageTables: 3680 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 4063220 kB Committed_AS: 125088 kB VmallocTotal: 34359738367 kB VmallocUsed: 13156 kB VmallocChunk: 34359715916 kB HardwareCorrupted: 0 kB AnonHugePages: 0 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 6148 kB DirectMap2M: 2088960 kB </div><div><div class="h5"><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> <div><div> ----- Original Message ----- From: <a href="mailto:michael.coffman@avagotech.com" target="_blank">michael.coffman@avagotech.com</a> To: <a href="mailto:centos@centos.org" target="_blank">centos@centos.org</a>, <a href="mailto:rhelv6-list@redhat.com" target="_blank">rhelv6-list@redhat.com</a> At: 5/17 15:12:12 Hello, In general I am in the habit of turning off memory overcommit because I believe it's a bad thing in a multi-user environment. This was never a problem on rhel5 systems, but on rhel6, I am having issues. When I try to set overcommit_memory=2, my system locks up. It basically behaves as if the memory is all used up... I see the same behavior on centos6 or rhel6. Following is some output from each platform. # -- RHEL6 # uname -a Linux joker 2.6.32-220.el6.x86_64 #1 SMP Wed Nov 9 08:03:13 EST 2011 x86_64 x86_64 x86_64 GNU/Linux #lsb_release -a LSB Version: :core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch Distributor ID: RedHatEnterpriseWorkstation Description: Red Hat Enterprise Linux Workstation release 6.2 (Santiago) Release: 6.2 Codename: Santiago # free total used free shared buffers cached Mem: 2052176 234828 1817348 0 15352 112852 -/+ buffers/cache: 106624 1945552 Swap: 2052088 0 2052088 # sysctl -a |grep commit vm.overcommit_memory = 0 vm.overcommit_ratio = 50 vm.nr_overcommit_hugepages = 0 # sysctl -w vm.overcommit_memory=2 vm.overcommit_memory = 2 # ls -bash: fork: Cannot allocate memory # #--- CENTOS6 -------------------------- # uname -a Linux joker 2.6.32-220.el6.x86_64 #1 SMP Tue Dec 6 19:48:22 GMT 2011 x86_64 x86_64 x86_64 GNU/Linux # lsb_release -a LSB Version: :core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch Distributor ID: CentOS Description: CentOS release 6.2 (Final) Release: 6.2 Codename: Final # free total used free shared buffers cached Mem: 2052176 378668 1673508 0 19472 252576 -/+ buffers/cache: 106620 1945556 Swap: 2052088 0 2052088 # sysctl -a |grep commit vm.overcommit_memory = 0 vm.overcommit_ratio = 50 vm.nr_overcommit_hugepages = 0 # sysctl -w vm.overcommit_memory=2 vm.overcommit_memory = 2 [root@joker ~]# ls -bash: fork: Cannot allocate memory One last point. If I set the overcommit values in /etc/sysctl.conf and then reboot, the values get set correctly on boot and everything seems fine. In addition I can then change the value of overcommit_memory to 0 and back to 2 with out any ill affects. Searches for issues with setting overcommit_memory=2 haven't turned up anything useful.. Thanks. -- -MichaelC</div></div></blockquote></div></div></div> -- -MichaelC </blockquote></div> -- -MichaelC