The patch titled
memrlimit: add memrlimit controller documentation
has been added to the -mm tree. Its filename is
memrlimit-add-memrlimit-controller-documentation.patch
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------------------------------------------------------
Subject: memrlimit: add memrlimit controller documentation
From: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
The goal of this patch is to implement a virtual address space controller
using cgroups. The documentation describes the controller, its goal and
usage in further detail.
This patch:
Documentation patch - describes the goals and usage of the memrlimit
controller.
Signed-off-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Cc: Sudhir Kumar <skumar@xxxxxxxxxxxxxxxxxx>
Cc: YAMAMOTO Takashi <yamamoto@xxxxxxxxxxxxx>
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Pavel Emelianov <xemul@xxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/controllers/memrlimit.txt | 29 ++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff -puN /dev/null Documentation/controllers/memrlimit.txt
--- /dev/null
+++ a/Documentation/controllers/memrlimit.txt
@@ -0,0 +1,29 @@
+This controller is enabled by the CONFIG_CGROUP_MEMRLIMIT_CTLR option. Prior
+to reading this documentation please read Documentation/cgroups.txt and
+Documentation/controllers/memory.txt. Several of the principles of this
+controller are similar to the memory resource controller.
+
+This controller framework is designed to be extensible to control any
+memory resource limit with little effort.
+
+This new controller, controls the address space expansion of the tasks
+belonging to a cgroup. Address space control is provided along the same lines as
+RLIMIT_AS control, which is available via getrlimit(2)/setrlimit(2).
+The interface for controlling address space is provided through
+"rlimit.limit_in_bytes". The file is similar to "limit_in_bytes" w.r.t. the user
+interface. Please see section 3 of the memory resource controller documentation
+for more details on how to use the user interface to get and set values.
+
+The "memrlimit.usage_in_bytes" file provides information about the total address
+space usage of the tasks in the cgroup, in bytes.
+
+Advantages of providing this feature
+
+1. Control over virtual address space allows for a cgroup to fail gracefully
+ i.e., via a malloc or mmap failure as compared to OOM kill when no
+ pages can be reclaimed.
+2. It provides better control over how many pages can be swapped out when
+ the cgroup goes over its limit. A badly setup cgroup can cause excessive
+ swapping. Providing control over the address space allocations ensures
+ that the system administrator has control over the total swapping that
+ can take place.
_
Patches currently in -mm which might be from balbir@xxxxxxxxxxxxxxxxxx are
linux-next.patch
cgroup-use-read-lock-to-guard-find_existing_css_set.patch
mark-res_counter_charge_locked-with-__must_check.patch
memcg-make-global-var-read_mostly.patch
memcg-avoid-unnecessary-initialization.patch
memrlimit-add-memrlimit-controller-documentation.patch
memrlimit-setup-the-memrlimit-controller.patch
memrlimit-cgroup-mm-owner-callback-changes-to-add-task-info.patch
memrlimit-add-memrlimit-controller-accounting-and-control.patch
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