Based on kernel version 4.3. Page generated on 2015-11-02 12:44 EST.
1 HugeTLB Controller 2 ------------------- 3 4 The HugeTLB controller allows to limit the HugeTLB usage per control group and 5 enforces the controller limit during page fault. Since HugeTLB doesn't 6 support page reclaim, enforcing the limit at page fault time implies that, 7 the application will get SIGBUS signal if it tries to access HugeTLB pages 8 beyond its limit. This requires the application to know beforehand how much 9 HugeTLB pages it would require for its use. 10 11 HugeTLB controller can be created by first mounting the cgroup filesystem. 12 13 # mount -t cgroup -o hugetlb none /sys/fs/cgroup 14 15 With the above step, the initial or the parent HugeTLB group becomes 16 visible at /sys/fs/cgroup. At bootup, this group includes all the tasks in 17 the system. /sys/fs/cgroup/tasks lists the tasks in this cgroup. 18 19 New 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 25 The above steps create a new group g1 and move the current shell 26 process (bash) into it. 27 28 Brief 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 usage for "hugepagesize" hugetlb 33 hugetlb.<hugepagesize>.failcnt # show the number of allocation failure due to HugeTLB limit 34 35 For a system supporting two hugepage size (16M and 16G) the control 36 files include: 37 38 hugetlb.16GB.limit_in_bytes 39 hugetlb.16GB.max_usage_in_bytes 40 hugetlb.16GB.usage_in_bytes 41 hugetlb.16GB.failcnt 42 hugetlb.16MB.limit_in_bytes 43 hugetlb.16MB.max_usage_in_bytes 44 hugetlb.16MB.usage_in_bytes 45 hugetlb.16MB.failcnt