Difference between revisions of "Memory"

Revision as of 16:01, 26 July 2018

https://access.redhat.com/solutions/46111 for Fedora and RHEL Note: their commands at the end of the article for determining if HugePages are disabled do not work in my limited tests. I have both Ubuntu and CentOS systems which are using HugePages, yet grep -i HugePages_Total /proc/meminfo cat /proc/sys/vm/nr_hugepages and sysctl vm.nr_hugepages all report zero. Meanwhile grep AnonHugePages /proc/meminfo and grep -e AnonHugePages /proc/*/smaps | awk '{ if($2>4) print $0} ' | awk -F "/" '{print $0; system("ps -fp " $3)} ' report actual usage. The biggest applications? mysqld, java, python, node, polkitd, mongod, httpd

Strangely, the value for cat /sys/kernel/mm/transparent_hugepage/enabled

[always] madvise never

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 Strangely, the value for <code>cat /sys/kernel/mm/transparent_hugepage/enabled</code>
 <pre>[always] madvise never</pre>
-Note that in order to enable or disable THP ''permanently'' (so that it survives reboots), you need to do more than just echo a value to <code>/sys/kernel/mm/transparent_hugepage/enabled</code>. And there are subtle differences between distros. <ref>https://askubuntu.com/questions/597372/how-do-i-modify-sys-kernel-mm-transparent-hugepage-enabled</ref>
 [[Category:System Administration]]