Re: [PATCH -V8 16/16] hugetlb/cgroup: add HugeTLB controller documentation
From: Kamezawa Hiroyuki <hidden>
Date: 2012-06-12 09:00:00
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cgroups, lkml
(2012/06/09 18:00), Aneesh Kumar K.V wrote:
From: "Aneesh Kumar K.V"<redacted> Signed-off-by: Aneesh Kumar K.V<redacted>
Documentation in patch 1/16 will help other guy's review.
quoted hunk ↗ jump to hunk
--- Documentation/cgroups/hugetlb.txt | 45 +++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 Documentation/cgroups/hugetlb.txtdiff --git a/Documentation/cgroups/hugetlb.txt b/Documentation/cgroups/hugetlb.txt new file mode 100644 index 0000000..a9faaca --- /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. +
Isn't it better to mention hugetlb cgroup doesn't have its own free-huge-page-list, it's just a quota. And system admin need to set up hugetlb page pool regardless of using hugetlb cgroup.
+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.<hugepagesize>.limit_in_bytes # set/show limit of "hugepagesize" hugetlb usage + hugetlb.<hugepagesize>.max_usage_in_bytes # show max "hugepagesize" hugetlb usage recorded + hugetlb.<hugepagesize>.usage_in_bytes # show current res_counter usage for "hugepagesize" hugetlb + hugetlb.<hugepagesize>.failcnt # show the number of allocation failure due to HugeTLB limit
^^^^^^^^ breakage in spacing.
+ +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
seems nice. Reviewed-by: KAMEZAWA Hiroyuki <redacted> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>