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r: 166894
b: refs/heads/master
c: e69a9ac
h: refs/heads/master
v: v3
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Linus Torvalds committed Oct 5, 2009
1 parent 1aa3209 commit f590031
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2 changes: 1 addition & 1 deletion [refs]
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@@ -1,2 +1,2 @@
---
refs/heads/master: d3f6302e7e51b41af86c6496ffb2f95e8f2179df
refs/heads/master: e69a9ac59629db81971a9e03048f9a107712947a
28 changes: 28 additions & 0 deletions trunk/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss
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Expand Up @@ -31,3 +31,31 @@ Date: March 2009
Kernel Version: 2.6.30
Contact: iss_storagedev@hp.com
Description: A symbolic link to /sys/block/cciss!cXdY

Where: /sys/bus/pci/devices/<dev>/ccissX/rescan
Date: August 2009
Kernel Version: 2.6.31
Contact: iss_storagedev@hp.com
Description: Kicks of a rescan of the controller to discover logical
drive topology changes.

Where: /sys/bus/pci/devices/<dev>/ccissX/cXdY/lunid
Date: August 2009
Kernel Version: 2.6.31
Contact: iss_storagedev@hp.com
Description: Displays the 8-byte LUN ID used to address logical
drive Y of controller X.

Where: /sys/bus/pci/devices/<dev>/ccissX/cXdY/raid_level
Date: August 2009
Kernel Version: 2.6.31
Contact: iss_storagedev@hp.com
Description: Displays the RAID level of logical drive Y of
controller X.

Where: /sys/bus/pci/devices/<dev>/ccissX/cXdY/usage_count
Date: August 2009
Kernel Version: 2.6.31
Contact: iss_storagedev@hp.com
Description: Displays the usage count (number of opens) of logical drive Y
of controller X.
2 changes: 1 addition & 1 deletion trunk/Documentation/SubmittingPatches
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Expand Up @@ -232,7 +232,7 @@ your e-mail client so that it sends your patches untouched.
When sending patches to Linus, always follow step #7.

Large changes are not appropriate for mailing lists, and some
maintainers. If your patch, uncompressed, exceeds 40 kB in size,
maintainers. If your patch, uncompressed, exceeds 300 kB in size,
it is preferred that you store your patch on an Internet-accessible
server, and provide instead a URL (link) pointing to your patch.

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147 changes: 147 additions & 0 deletions trunk/Documentation/arm/tcm.txt
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@@ -0,0 +1,147 @@
ARM TCM (Tightly-Coupled Memory) handling in Linux
----
Written by Linus Walleij <linus.walleij@stericsson.com>

Some ARM SoC:s have a so-called TCM (Tightly-Coupled Memory).
This is usually just a few (4-64) KiB of RAM inside the ARM
processor.

Due to being embedded inside the CPU The TCM has a
Harvard-architecture, so there is an ITCM (instruction TCM)
and a DTCM (data TCM). The DTCM can not contain any
instructions, but the ITCM can actually contain data.
The size of DTCM or ITCM is minimum 4KiB so the typical
minimum configuration is 4KiB ITCM and 4KiB DTCM.

ARM CPU:s have special registers to read out status, physical
location and size of TCM memories. arch/arm/include/asm/cputype.h
defines a CPUID_TCM register that you can read out from the
system control coprocessor. Documentation from ARM can be found
at http://infocenter.arm.com, search for "TCM Status Register"
to see documents for all CPUs. Reading this register you can
determine if ITCM (bit 0) and/or DTCM (bit 16) is present in the
machine.

There is further a TCM region register (search for "TCM Region
Registers" at the ARM site) that can report and modify the location
size of TCM memories at runtime. This is used to read out and modify
TCM location and size. Notice that this is not a MMU table: you
actually move the physical location of the TCM around. At the
place you put it, it will mask any underlying RAM from the
CPU so it is usually wise not to overlap any physical RAM with
the TCM.

The TCM memory can then be remapped to another address again using
the MMU, but notice that the TCM if often used in situations where
the MMU is turned off. To avoid confusion the current Linux
implementation will map the TCM 1 to 1 from physical to virtual
memory in the location specified by the machine.

TCM is used for a few things:

- FIQ and other interrupt handlers that need deterministic
timing and cannot wait for cache misses.

- Idle loops where all external RAM is set to self-refresh
retention mode, so only on-chip RAM is accessible by
the CPU and then we hang inside ITCM waiting for an
interrupt.

- Other operations which implies shutting off or reconfiguring
the external RAM controller.

There is an interface for using TCM on the ARM architecture
in <asm/tcm.h>. Using this interface it is possible to:

- Define the physical address and size of ITCM and DTCM.

- Tag functions to be compiled into ITCM.

- Tag data and constants to be allocated to DTCM and ITCM.

- Have the remaining TCM RAM added to a special
allocation pool with gen_pool_create() and gen_pool_add()
and provice tcm_alloc() and tcm_free() for this
memory. Such a heap is great for things like saving
device state when shutting off device power domains.

A machine that has TCM memory shall select HAVE_TCM in
arch/arm/Kconfig for itself, and then the
rest of the functionality will depend on the physical
location and size of ITCM and DTCM to be defined in
mach/memory.h for the machine. Code that needs to use
TCM shall #include <asm/tcm.h> If the TCM is not located
at the place given in memory.h it will be moved using
the TCM Region registers.

Functions to go into itcm can be tagged like this:
int __tcmfunc foo(int bar);

Variables to go into dtcm can be tagged like this:
int __tcmdata foo;

Constants can be tagged like this:
int __tcmconst foo;

To put assembler into TCM just use
.section ".tcm.text" or .section ".tcm.data"
respectively.

Example code:

#include <asm/tcm.h>

/* Uninitialized data */
static u32 __tcmdata tcmvar;
/* Initialized data */
static u32 __tcmdata tcmassigned = 0x2BADBABEU;
/* Constant */
static const u32 __tcmconst tcmconst = 0xCAFEBABEU;

static void __tcmlocalfunc tcm_to_tcm(void)
{
int i;
for (i = 0; i < 100; i++)
tcmvar ++;
}

static void __tcmfunc hello_tcm(void)
{
/* Some abstract code that runs in ITCM */
int i;
for (i = 0; i < 100; i++) {
tcmvar ++;
}
tcm_to_tcm();
}

static void __init test_tcm(void)
{
u32 *tcmem;
int i;

hello_tcm();
printk("Hello TCM executed from ITCM RAM\n");

printk("TCM variable from testrun: %u @ %p\n", tcmvar, &tcmvar);
tcmvar = 0xDEADBEEFU;
printk("TCM variable: 0x%x @ %p\n", tcmvar, &tcmvar);

printk("TCM assigned variable: 0x%x @ %p\n", tcmassigned, &tcmassigned);

printk("TCM constant: 0x%x @ %p\n", tcmconst, &tcmconst);

/* Allocate some TCM memory from the pool */
tcmem = tcm_alloc(20);
if (tcmem) {
printk("TCM Allocated 20 bytes of TCM @ %p\n", tcmem);
tcmem[0] = 0xDEADBEEFU;
tcmem[1] = 0x2BADBABEU;
tcmem[2] = 0xCAFEBABEU;
tcmem[3] = 0xDEADBEEFU;
tcmem[4] = 0x2BADBABEU;
for (i = 0; i < 5; i++)
printk("TCM tcmem[%d] = %08x\n", i, tcmem[i]);
tcm_free(tcmem, 20);
}
}
1 change: 0 additions & 1 deletion trunk/Documentation/auxdisplay/cfag12864b-example.c
Original file line number Diff line number Diff line change
Expand Up @@ -194,7 +194,6 @@ static void cfag12864b_blit(void)
*/

#include <stdio.h>
#include <string.h>

#define EXAMPLES 6

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32 changes: 29 additions & 3 deletions trunk/Documentation/cgroups/cgroups.txt
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Expand Up @@ -408,6 +408,26 @@ You can attach the current shell task by echoing 0:

# echo 0 > tasks

2.3 Mounting hierarchies by name
--------------------------------

Passing the name=<x> option when mounting a cgroups hierarchy
associates the given name with the hierarchy. This can be used when
mounting a pre-existing hierarchy, in order to refer to it by name
rather than by its set of active subsystems. Each hierarchy is either
nameless, or has a unique name.

The name should match [\w.-]+

When passing a name=<x> option for a new hierarchy, you need to
specify subsystems manually; the legacy behaviour of mounting all
subsystems when none are explicitly specified is not supported when
you give a subsystem a name.

The name of the subsystem appears as part of the hierarchy description
in /proc/mounts and /proc/<pid>/cgroups.


3. Kernel API
=============

Expand Down Expand Up @@ -501,22 +521,28 @@ rmdir() will fail with it. From this behavior, pre_destroy() can be
called multiple times against a cgroup.

int can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct task_struct *task)
struct task_struct *task, bool threadgroup)
(cgroup_mutex held by caller)

Called prior to moving a task into a cgroup; if the subsystem
returns an error, this will abort the attach operation. If a NULL
task is passed, then a successful result indicates that *any*
unspecified task can be moved into the cgroup. Note that this isn't
called on a fork. If this method returns 0 (success) then this should
remain valid while the caller holds cgroup_mutex.
remain valid while the caller holds cgroup_mutex. If threadgroup is
true, then a successful result indicates that all threads in the given
thread's threadgroup can be moved together.

void attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup *old_cgrp, struct task_struct *task)
struct cgroup *old_cgrp, struct task_struct *task,
bool threadgroup)
(cgroup_mutex held by caller)

Called after the task has been attached to the cgroup, to allow any
post-attachment activity that requires memory allocations or blocking.
If threadgroup is true, the subsystem should take care of all threads
in the specified thread's threadgroup. Currently does not support any
subsystem that might need the old_cgrp for every thread in the group.

void fork(struct cgroup_subsy *ss, struct task_struct *task)

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41 changes: 40 additions & 1 deletion trunk/Documentation/cgroups/memory.txt
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Expand Up @@ -179,6 +179,9 @@ The reclaim algorithm has not been modified for cgroups, except that
pages that are selected for reclaiming come from the per cgroup LRU
list.

NOTE: Reclaim does not work for the root cgroup, since we cannot set any
limits on the root cgroup.

2. Locking

The memory controller uses the following hierarchy
Expand Down Expand Up @@ -210,6 +213,7 @@ We can alter the memory limit:
NOTE: We can use a suffix (k, K, m, M, g or G) to indicate values in kilo,
mega or gigabytes.
NOTE: We can write "-1" to reset the *.limit_in_bytes(unlimited).
NOTE: We cannot set limits on the root cgroup any more.

# cat /cgroups/0/memory.limit_in_bytes
4194304
Expand Down Expand Up @@ -375,7 +379,42 @@ cgroups created below it.

NOTE2: This feature can be enabled/disabled per subtree.

7. TODO
7. Soft limits

Soft limits allow for greater sharing of memory. The idea behind soft limits
is to allow control groups to use as much of the memory as needed, provided

a. There is no memory contention
b. They do not exceed their hard limit

When the system detects memory contention or low memory control groups
are pushed back to their soft limits. If the soft limit of each control
group is very high, they are pushed back as much as possible to make
sure that one control group does not starve the others of memory.

Please note that soft limits is a best effort feature, it comes with
no guarantees, but it does its best to make sure that when memory is
heavily contended for, memory is allocated based on the soft limit
hints/setup. Currently soft limit based reclaim is setup such that
it gets invoked from balance_pgdat (kswapd).

7.1 Interface

Soft limits can be setup by using the following commands (in this example we
assume a soft limit of 256 megabytes)

# echo 256M > memory.soft_limit_in_bytes

If we want to change this to 1G, we can at any time use

# echo 1G > memory.soft_limit_in_bytes

NOTE1: Soft limits take effect over a long period of time, since they involve
reclaiming memory for balancing between memory cgroups
NOTE2: It is recommended to set the soft limit always below the hard limit,
otherwise the hard limit will take precedence.

8. TODO

1. Add support for accounting huge pages (as a separate controller)
2. Make per-cgroup scanner reclaim not-shared pages first
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2 changes: 1 addition & 1 deletion trunk/Documentation/connector/cn_test.c
Original file line number Diff line number Diff line change
Expand Up @@ -34,7 +34,7 @@ static char cn_test_name[] = "cn_test";
static struct sock *nls;
static struct timer_list cn_test_timer;

static void cn_test_callback(struct cn_msg *msg)
static void cn_test_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
{
pr_info("%s: %lu: idx=%x, val=%x, seq=%u, ack=%u, len=%d: %s.\n",
__func__, jiffies, msg->id.idx, msg->id.val,
Expand Down
8 changes: 4 additions & 4 deletions trunk/Documentation/connector/connector.txt
Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ handling, etc... The Connector driver allows any kernelspace agents to use
netlink based networking for inter-process communication in a significantly
easier way:

int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *));
int cn_add_callback(struct cb_id *id, char *name, void (*callback) (struct cn_msg *, struct netlink_skb_parms *));
void cn_netlink_send(struct cn_msg *msg, u32 __group, int gfp_mask);

struct cb_id
Expand Down Expand Up @@ -53,15 +53,15 @@ struct cn_msg
Connector interfaces.
/*****************************************/

int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *));
int cn_add_callback(struct cb_id *id, char *name, void (*callback) (struct cn_msg *, struct netlink_skb_parms *));

Registers new callback with connector core.

struct cb_id *id - unique connector's user identifier.
It must be registered in connector.h for legal in-kernel users.
char *name - connector's callback symbolic name.
void (*callback) (void *) - connector's callback.
Argument must be dereferenced to struct cn_msg *.
void (*callback) (struct cn..) - connector's callback.
cn_msg and the sender's credentials


void cn_del_callback(struct cb_id *id);
Expand Down
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