From 0faeea4b3a337d673ed5446a2ef114bb8d2847df Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Wed, 25 Apr 2012 11:03:39 +1000 Subject: [PATCH] memcg: add memory controller documentation for hugetlb management Signed-off-by: Aneesh Kumar K.V Cc: KAMEZAWA Hiroyuki Cc: Hillf Danton Cc: Michal Hocko Cc: Andrea Arcangeli Cc: Johannes Weiner Signed-off-by: Andrew Morton --- Documentation/cgroups/memory.txt | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index 9b1067afb224..a00aa6041bac 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -42,6 +42,7 @@ Features: - usage threshold notifier - oom-killer disable knob and oom-notifier - Root cgroup has no limit controls. + - resource accounting for HugeTLB pages Kernel memory support is work in progress, and the current version provides basically functionality. (See Section 2.7) @@ -74,6 +75,12 @@ Brief summary of control files. memory.kmem.tcp.limit_in_bytes # set/show hard limit for tcp buf memory memory.kmem.tcp.usage_in_bytes # show current tcp buf memory allocation + + memory.hugetlb..limit_in_bytes # set/show limit of "hugepagesize" hugetlb usage + memory.hugetlb..max_usage_in_bytes # show max "hugepagesize" hugetlb usage recorded + memory.hugetlb..usage_in_bytes # show current res_counter usage for "hugepagesize" hugetlb + # see 5.7 for details + 1. History The memory controller has a long history. A request for comments for the memory @@ -278,6 +285,15 @@ per cgroup, instead of globally. * tcp memory pressure: sockets memory pressure for the tcp protocol. +2.8 HugeTLB extension + +This extension 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. + 3. User Interface 0. Configuration @@ -286,6 +302,7 @@ a. Enable CONFIG_CGROUPS b. Enable CONFIG_RESOURCE_COUNTERS c. Enable CONFIG_CGROUP_MEM_RES_CTLR d. Enable CONFIG_CGROUP_MEM_RES_CTLR_SWAP (to use swap extension) +f. Enable CONFIG_MEM_RES_CTLR_HUGETLB (to use HugeTLB extension) 1. Prepare the cgroups (see cgroups.txt, Why are cgroups needed?) # mount -t tmpfs none /sys/fs/cgroup @@ -509,6 +526,18 @@ unevictable= N0= N1= ... And we have total = file + anon + unevictable. +5.7 HugeTLB resource control files +For a system supporting two hugepage size (16M and 16G) the control +files include: + + memory.hugetlb.16GB.limit_in_bytes + memory.hugetlb.16GB.max_usage_in_bytes + memory.hugetlb.16GB.usage_in_bytes + memory.hugetlb.16MB.limit_in_bytes + memory.hugetlb.16MB.max_usage_in_bytes + memory.hugetlb.16MB.usage_in_bytes + + 6. Hierarchy support The memory controller supports a deep hierarchy and hierarchical accounting. -- 2.39.5