Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

 - oom-killer disable knob and oom-notifier

 - Root cgroup has no limit controls.

 Kernel memory and Hugepages are not under control yet. We just manage

 pages on LRU. To add more controls, we have to take care of performance.

 Kernel memory support is work in progress, and the current version provides

 basically functionality. (See Section 2.7)

Brief summary of control files.

 memory.oom_control		 # set/show oom controls.

 memory.numa_stat		 # show the number of memory usage per numa node

 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

1. History

The memory controller has a long history. A request for comments for the memory

  per-zone-per-cgroup LRU (cgroup's private LRU) is just guarded by

  zone->lru_lock, it has no lock of its own.

2.7 Kernel Memory Extension (CONFIG_CGROUP_MEM_RES_CTLR_KMEM)

With the Kernel memory extension, the Memory Controller is able to limit

the amount of kernel memory used by the system. Kernel memory is fundamentally

different than user memory, since it can't be swapped out, which makes it

possible to DoS the system by consuming too much of this precious resource.

Kernel memory limits are not imposed for the root cgroup. Usage for the root

cgroup may or may not be accounted.

Currently no soft limit is implemented for kernel memory. It is future work

to trigger slab reclaim when those limits are reached.

2.7.1 Current Kernel Memory resources accounted

* sockets memory pressure: some sockets protocols have memory pressure

thresholds. The Memory Controller allows them to be controlled individually

per cgroup, instead of globally.

* tcp memory pressure: sockets memory pressure for the tcp protocol.

3. User Interface

0. Configuration

Network priority cgroup

-------------------------

The Network priority cgroup provides an interface to allow an administrator to

dynamically set the priority of network traffic generated by various

applications

Nominally, an application would set the priority of its traffic via the

SO_PRIORITY socket option.  This however, is not always possible because:

1) The application may not have been coded to set this value

2) The priority of application traffic is often a site-specific administrative

   decision rather than an application defined one.

This cgroup allows an administrator to assign a process to a group which defines

the priority of egress traffic on a given interface. Network priority groups can

be created by first mounting the cgroup filesystem.

# mount -t cgroup -onet_prio none /sys/fs/cgroup/net_prio

With the above step, the initial group acting as the parent accounting group

becomes visible at '/sys/fs/cgroup/net_prio'.  This group includes all tasks in

the system. '/sys/fs/cgroup/net_prio/tasks' lists the tasks in this cgroup.

Each net_prio cgroup contains two files that are subsystem specific

net_prio.prioidx

This file is read-only, and is simply informative.  It contains a unique integer

value that the kernel uses as an internal representation of this cgroup.

net_prio.ifpriomap

This file contains a map of the priorities assigned to traffic originating from

processes in this group and egressing the system on various interfaces. It

contains a list of tuples in the form <ifname priority>.  Contents of this file

can be modified by echoing a string into the file using the same tuple format.

for example:

echo "eth0 5" > /sys/fs/cgroups/net_prio/iscsi/net_prio.ifpriomap

This command would force any traffic originating from processes belonging to the

iscsi net_prio cgroup and egressing on interface eth0 to have the priority of

said traffic set to the value 5. The parent accounting group also has a

writeable 'net_prio.ifpriomap' file that can be used to set a system default

priority.

Priorities are set immediately prior to queueing a frame to the device

queueing discipline (qdisc) so priorities will be assigned prior to the hardware

queue selection being made.

One usage for the net_prio cgroup is with mqprio qdisc allowing application

traffic to be steered to hardware/driver based traffic classes. These mappings

can then be managed by administrators or other networking protocols such as

DCBX.

* Calxeda Highbank 10Gb XGMAC Ethernet

Required properties:

- compatible : Should be "calxeda,hb-xgmac"

- reg : Address and length of the register set for the device

- interrupts : Should contain 3 xgmac interrupts. The 1st is main interrupt.

  The 2nd is pwr mgt interrupt. The 3rd is low power state interrupt.

Example:

ethernet@fff50000 {

        compatible = "calxeda,hb-xgmac";

        reg = <0xfff50000 0x1000>;

        interrupts = <0 77 4  0 78 4  0 79 4>;

};

Memory mapped Bosch CC770 and Intel AN82527 CAN controller

Note: The CC770 is a CAN controller from Bosch, which is 100%

compatible with the old AN82527 from Intel, but with "bugs" being fixed.

Required properties:

- compatible : should be "bosch,cc770" for the CC770 and "intc,82527"

	for the AN82527.

- reg : should specify the chip select, address offset and size required

	to map the registers of the controller. The size is usually 0x80.

- interrupts : property with a value describing the interrupt source

	(number and sensitivity) required for the controller.

Optional properties:

- bosch,external-clock-frequency : frequency of the external oscillator

	clock in Hz. Note that the internal clock frequency used by the

	controller is half of that value. If not specified, a default

	value of 16000000 (16 MHz) is used.

- bosch,clock-out-frequency : slock frequency in Hz on the CLKOUT pin.

	If not specified or if the specified value is 0, the CLKOUT pin

	will be disabled.

- bosch,slew-rate : slew rate of the CLKOUT signal. If not specified,

	a resonable value will be calculated.

- bosch,disconnect-rx0-input : see data sheet.

- bosch,disconnect-rx1-input : see data sheet.

- bosch,disconnect-tx1-output : see data sheet.

- bosch,polarity-dominant : see data sheet.

- bosch,divide-memory-clock : see data sheet.

- bosch,iso-low-speed-mux : see data sheet.

For further information, please have a look to the CC770 or AN82527.

Examples:

can@3,100 {

	compatible = "bosch,cc770";

	reg = <3 0x100 0x80>;

	interrupts = <2 0>;

	interrupt-parent = <&mpic>;

	bosch,external-clock-frequency = <16000000>;

};

What:	Code that is now under CONFIG_WIRELESS_EXT_SYSFS

	(in net/core/net-sysfs.c)

When:	After the only user (hal) has seen a release with the patches

	for enough time, probably some time in 2010.

When:	3.5

Why:	Over 1K .text/.data size reduction, data is available in other

	ways (ioctls)

Who:	Johannes Berg <johannes@sipsolutions.net>