linux/Documentation/cgroups/hugetlb.txt
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   1HugeTLB Controller
   2-------------------
   3
   4The HugeTLB controller allows to limit the HugeTLB usage per control group and
   5enforces the controller limit during page fault. Since HugeTLB doesn't
   6support page reclaim, enforcing the limit at page fault time implies that,
   7the application will get SIGBUS signal if it tries to access HugeTLB pages
   8beyond its limit. This requires the application to know beforehand how much
   9HugeTLB pages it would require for its use.
  10
  11HugeTLB controller can be created by first mounting the cgroup filesystem.
  12
  13# mount -t cgroup -o hugetlb none /sys/fs/cgroup
  14
  15With the above step, the initial or the parent HugeTLB group becomes
  16visible at /sys/fs/cgroup. At bootup, this group includes all the tasks in
  17the system. /sys/fs/cgroup/tasks lists the tasks in this cgroup.
  18
  19New groups can be created under the parent group /sys/fs/cgroup.
  20
  21# cd /sys/fs/cgroup
  22# mkdir g1
  23# echo $$ > g1/tasks
  24
  25The above steps create a new group g1 and move the current shell
  26process (bash) into it.
  27
  28Brief summary of control files
  29
  30 hugetlb.<hugepagesize>.limit_in_bytes     # set/show limit of "hugepagesize" hugetlb usage
  31 hugetlb.<hugepagesize>.max_usage_in_bytes # show max "hugepagesize" hugetlb  usage recorded
  32 hugetlb.<hugepagesize>.usage_in_bytes     # show current res_counter usage for "hugepagesize" hugetlb
  33 hugetlb.<hugepagesize>.failcnt            # show the number of allocation failure due to HugeTLB limit
  34
  35For a system supporting two hugepage size (16M and 16G) the control
  36files include:
  37
  38hugetlb.16GB.limit_in_bytes
  39hugetlb.16GB.max_usage_in_bytes
  40hugetlb.16GB.usage_in_bytes
  41hugetlb.16GB.failcnt
  42hugetlb.16MB.limit_in_bytes
  43hugetlb.16MB.max_usage_in_bytes
  44hugetlb.16MB.usage_in_bytes
  45hugetlb.16MB.failcnt
  46
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