From 7d558cd9c7b18e4b16953265aa0da45e63f3b968 Mon Sep 17 00:00:00 2001 From: Anton Arapov Date: Mon, 29 Oct 2012 11:15:37 +0100 Subject: fedora kernel: cd394142aac30b5c751f25b517572e2448695641 Signed-off-by: Anton Arapov --- Documentation/cgroups/hugetlb.txt | 45 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 Documentation/cgroups/hugetlb.txt (limited to 'Documentation/cgroups/hugetlb.txt') diff --git a/Documentation/cgroups/hugetlb.txt b/Documentation/cgroups/hugetlb.txt new file mode 100644 index 00000000000..a9faaca1f02 --- /dev/null +++ b/Documentation/cgroups/hugetlb.txt @@ -0,0 +1,45 @@ +HugeTLB Controller +------------------- + +The HugeTLB controller allows to limit the HugeTLB usage per control group and +enforces the controller limit during page fault. Since HugeTLB doesn't +support page reclaim, enforcing the limit at page fault time implies that, +the application will get SIGBUS signal if it tries to access HugeTLB pages +beyond its limit. This requires the application to know beforehand how much +HugeTLB pages it would require for its use. + +HugeTLB controller can be created by first mounting the cgroup filesystem. + +# mount -t cgroup -o hugetlb none /sys/fs/cgroup + +With the above step, the initial or the parent HugeTLB group becomes +visible at /sys/fs/cgroup. At bootup, this group includes all the tasks in +the system. /sys/fs/cgroup/tasks lists the tasks in this cgroup. + +New groups can be created under the parent group /sys/fs/cgroup. + +# cd /sys/fs/cgroup +# mkdir g1 +# echo $$ > g1/tasks + +The above steps create a new group g1 and move the current shell +process (bash) into it. + +Brief summary of control files + + hugetlb..limit_in_bytes # set/show limit of "hugepagesize" hugetlb usage + hugetlb..max_usage_in_bytes # show max "hugepagesize" hugetlb usage recorded + hugetlb..usage_in_bytes # show current res_counter usage for "hugepagesize" hugetlb + hugetlb..failcnt # show the number of allocation failure due to HugeTLB limit + +For a system supporting two hugepage size (16M and 16G) the control +files include: + +hugetlb.16GB.limit_in_bytes +hugetlb.16GB.max_usage_in_bytes +hugetlb.16GB.usage_in_bytes +hugetlb.16GB.failcnt +hugetlb.16MB.limit_in_bytes +hugetlb.16MB.max_usage_in_bytes +hugetlb.16MB.usage_in_bytes +hugetlb.16MB.failcnt -- cgit