Commit Graph

23 Commits

Author SHA1 Message Date
Linus Torvalds f310642123 Merge branch 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6
* 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6:
  x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param
  x86 idle: deprecate "no-hlt" cmdline param
  x86 idle APM: deprecate CONFIG_APM_CPU_IDLE
  x86 idle floppy: deprecate disable_hlt()
  x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it
  x86 idle: clarify AMD erratum 400 workaround
  idle governor: Avoid lock acquisition to read pm_qos before entering idle
  cpuidle: menu: fixed wrapping timers at 4.294 seconds
2011-05-29 11:18:09 -07:00
Tim Chen 333c5ae994 idle governor: Avoid lock acquisition to read pm_qos before entering idle
Thanks to the reviews and comments by Rafael, James, Mark and Andi.
Here's version 2 of the patch incorporating your comments and also some
update to my previous patch comments.

I noticed that before entering idle state, the menu idle governor will
look up the current pm_qos target value according to the list of qos
requests received.  This look up currently needs the acquisition of a
lock to access the list of qos requests to find the qos target value,
slowing down the entrance into idle state due to contention by multiple
cpus to access this list.  The contention is severe when there are a lot
of cpus waking and going into idle.  For example, for a simple workload
that has 32 pair of processes ping ponging messages to each other, where
64 cpu cores are active in test system, I see the following profile with
37.82% of cpu cycles spent in contention of pm_qos_lock:

-     37.82%          swapper  [kernel.kallsyms]          [k]
_raw_spin_lock_irqsave
   - _raw_spin_lock_irqsave
      - 95.65% pm_qos_request
           menu_select
           cpuidle_idle_call
         - cpu_idle
              99.98% start_secondary

A better approach will be to cache the updated pm_qos target value so
reading it does not require lock acquisition as in the patch below.
With this patch the contention for pm_qos_lock is removed and I saw a
2.2X increase in throughput for my message passing workload.

cc: stable@kernel.org
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: James Bottomley <James.Bottomley@suse.de>
Acked-by: mark gross <markgross@thegnar.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-05-29 00:50:59 -04:00
Linus Torvalds f23a5e1405 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
  PM: Fix PM QOS's user mode interface to work with ASCII input
  PM / Hibernate: Update kerneldoc comments in hibernate.c
  PM / Hibernate: Remove arch_prepare_suspend()
  PM / Hibernate: Update some comments in core hibernate code
2011-05-27 14:27:34 -07:00
Rafael J. Wysocki 0775a60aca PM: Fix PM QOS's user mode interface to work with ASCII input
Make pm_qos_power_write() accept values passed to it in the ASCII hex
format either with or without an ending newline.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Mark Gross <markgross@thegnar.org>
2011-05-27 00:05:23 +02:00
Justin P. Mattock 6eab04a876 treewide: remove extra semicolons
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-04-10 17:01:05 +02:00
Thomas Renninger f9b9e806ae PM QoS: Make pm_qos settings readable
I have a machine where entering deep C-states broke.
pm_qos was a hot candidate, but I couldn't find any way to double
check without the need of recompiling.

While in this case it was a driver bug (ath9k):
https://bugzilla.kernel.org/show_bug.cgi?id=27532

powertop or others may want to read out cpu_dma_latency
restrictions which could be the cause of preventing a machine
entering deeper C-states.

Output with this patch:

# default value of 2000 * USEC_PER_SEC (0x77359400)
cat /dev/network_latency |hexdump
0000000 9400 7735
0000004

# value of 55 us which is the reason for not entering C2
cat /dev/cpu_dma_latency |hexdump
0000000 0037 0000
0000004

There is no reason to hide this info -> make pm_qos files readable.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-15 00:43:18 +01:00
Colin Cross 00fafcda17 PM / PM QoS: Fix reversed min and max
pm_qos_get_value had min and max reversed, causing all pm_qos
requests to have no effect.

Signed-off-by: Colin Cross <ccross@android.com>
Acked-by: mark <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
2010-11-15 22:45:22 +01:00
Linus Torvalds 229aebb873 Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
  Update broken web addresses in arch directory.
  Update broken web addresses in the kernel.
  Revert "drivers/usb: Remove unnecessary return's from void functions" for musb gadget
  Revert "Fix typo: configuation => configuration" partially
  ida: document IDA_BITMAP_LONGS calculation
  ext2: fix a typo on comment in ext2/inode.c
  drivers/scsi: Remove unnecessary casts of private_data
  drivers/s390: Remove unnecessary casts of private_data
  net/sunrpc/rpc_pipe.c: Remove unnecessary casts of private_data
  drivers/infiniband: Remove unnecessary casts of private_data
  drivers/gpu/drm: Remove unnecessary casts of private_data
  kernel/pm_qos_params.c: Remove unnecessary casts of private_data
  fs/ecryptfs: Remove unnecessary casts of private_data
  fs/seq_file.c: Remove unnecessary casts of private_data
  arm: uengine.c: remove C99 comments
  arm: scoop.c: remove C99 comments
  Fix typo configue => configure in comments
  Fix typo: configuation => configuration
  Fix typo interrest[ing|ed] => interest[ing|ed]
  Fix various typos of valid in comments
  ...

Fix up trivial conflicts in:
	drivers/char/ipmi/ipmi_si_intf.c
	drivers/usb/gadget/rndis.c
	net/irda/irnet/irnet_ppp.c
2010-10-24 13:41:39 -07:00
Arnd Bergmann 6038f373a3 llseek: automatically add .llseek fop
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
2010-10-15 15:53:27 +02:00
Joe Perches 99a51792db kernel/pm_qos_params.c: Remove unnecessary casts of private_data
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-09-23 13:33:46 +02:00
mark gross 0109c2c48d PM QoS: Correct pr_debug() misuse and improve parameter checks
Correct some pr_debug() misuse and add a stronger parameter check to
pm_qos_write() for the ASCII hex value case.  Thanks to Dan Carpenter
for pointing out the problem!

Signed-off-by: mark gross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-09-11 00:53:05 +02:00
Saravana Kannan 25cc69ec34 PM QoS: Fix inline documentation.
Fix the pm_qos_add_request() kerneldoc comment that doesn't reflect
the behavior of the function after the last PM QoS update.

Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Acked-by: mark gross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-08-26 20:18:43 +02:00
David Alan Gilbert bac1e74dba PM QoS: Fix kzalloc() parameters swapped in pm_qos_power_open()
sparse spotted that the kzalloc() in pm_qos_power_open() in the
current Linus' git tree had its parameters swapped.  Fix this.

Signed-off-by: David Alan Gilbert <linux@treblig.org>
Acked-by: mark gross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-08-24 20:22:18 +02:00
James Bottomley 82f682514a pm_qos: Get rid of the allocation in pm_qos_add_request()
All current users of pm_qos_add_request() have the ability to supply
the memory required by the pm_qos routines, so make them do this and
eliminate the kmalloc() with pm_qos_add_request().  This has the
double benefit of making the call never fail and allowing it to be
called from atomic context.

Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: mark gross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-07-19 02:00:34 +02:00
James Bottomley 5f279845f9 pm_qos: Reimplement using plists
A lot of the pm_qos extremal value handling is really duplicating what a
priority ordered list does, just in a less efficient fashion.  Simply
redoing the implementation in terms of a plist gets rid of a lot of this
junk (although there are several other strange things that could do with
tidying up, like pm_qos_request_list has to carry the pm_qos_class with
every node, simply because it doesn't get passed in to
pm_qos_update_request even though every caller knows full well what
parameter it's updating).

I think this redo is a win independent of android, so we should do
something like this now.

Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: mark gross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-07-19 02:00:18 +02:00
Mark Gross 25f3a5a285 PM: PM QOS update fix
This update handles a use case where pm_qos update requests need to
silently fail if the update is being sent to a handle that is NULL.

The problem was that the original pm_qos silently fails when a request
update is passed to a parameter that has not been added to the list yet.
This update restores that behavior.

Signed-off-by: markgross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-05-17 00:21:03 +02:00
Mark Gross ed77134bfc PM QOS update
This patch changes the string based list management to a handle base
implementation to help with the hot path use of pm-qos, it also renames
much of the API to use "request" as opposed to "requirement" that was
used in the initial implementation.  I did this because request more
accurately represents what it actually does.

Also, I added a string based ABI for users wanting to use a string
interface.  So if the user writes 0xDDDDDDDD formatted hex it will be
accepted by the interface.  (someone asked me for it and I don't think
it hurts anything.)

This patch updates some documentation input I got from Randy.

Signed-off-by: markgross <mgross@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-05-10 23:08:19 +02:00
Jonathan Corbet 1a6deaea35 pm_qos: clean up racy global "name" variable
"name" is a poor name for a file-global variable.  It was used in three
different functions, with no mutual exclusion.  But it's just a tiny,
temporary string; let's just move it onto the stack in the functions that
need it.  Also use snprintf() just in case.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
LKML-Reference: <20091010153349.113570550@linutronix.de>
Acked-by: Mark Gross <mgross@linux.intel.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-10-14 15:31:10 +02:00
Jonathan Corbet e6fe07a014 pm_qos: remove BKL
pm_qos_power_open got its lock_kernel() calls from the open() pushdown.  A
look at the code shows that the only global resources accessed are
pm_qos_array and "name".  pm_qos_array doesn't change (things pointed to
therein do change, but they are atomics and/or are protected by
pm_qos_lock).  Accesses to "name" are totally unprotected with or without
the BKL; that will be fixed shortly.  The BKL is not helpful here; take it
out.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
LKML-Reference: <20091010153349.071381158@linutronix.de>
Acked-by: Mark Gross <mgross@linux.intel.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-10-14 15:31:10 +02:00
John Kacur 9d35935747 pm_qos_requirement might sleep
Make PM_QOS and CPU_IDLE play nicer when run with the RT-Preempt kernel.

The purpose of the patch is to remove the spin_lock around the read in the
function pm_qos_requirement - since spinlocks can sleep in -rt and this
function is called from idle.

CPU_IDLE polls the target_value's of some of the pm_qos parameters from
the idle loop causing sleeping locking warnings.  Changing the
target_value to an atomic avoids this issue.

Remove the spinlock in pm_qos_requirement by making target_value an atomic
type.

Signed-off-by: mark gross <mgross@linux.intel.com>
Signed-off-by: John Kacur <jkacur@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-02 19:21:40 -07:00
Richard Hughes bf1db69fbf pm_qos: spelling fixes
A documentation cleanup patch.  With a minor tweak to clarify units for
kbs.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: mark gross <mgross@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-05 14:33:50 -07:00
Arnd Bergmann db26e64dc3 pm_qos_params: BKL pushdown
[jmc: added <linux/smp_lock.h>]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2008-07-02 15:06:24 -06:00
Mark Gross d82b35186e pm qos infrastructure and interface
The following patch is a generalization of the latency.c implementation done
by Arjan last year.  It provides infrastructure for more than one parameter,
and exposes a user mode interface for processes to register pm_qos
expectations of processes.

This interface provides a kernel and user mode interface for registering
performance expectations by drivers, subsystems and user space applications on
one of the parameters.

Currently we have {cpu_dma_latency, network_latency, network_throughput} as
the initial set of pm_qos parameters.

The infrastructure exposes multiple misc device nodes one per implemented
parameter.  The set of parameters implement is defined by pm_qos_power_init()
and pm_qos_params.h.  This is done because having the available parameters
being runtime configurable or changeable from a driver was seen as too easy to
abuse.

For each parameter a list of performance requirements is maintained along with
an aggregated target value.  The aggregated target value is updated with
changes to the requirement list or elements of the list.  Typically the
aggregated target value is simply the max or min of the requirement values
held in the parameter list elements.

>From kernel mode the use of this interface is simple:

pm_qos_add_requirement(param_id, name, target_value):

  Will insert a named element in the list for that identified PM_QOS
  parameter with the target value.  Upon change to this list the new target is
  recomputed and any registered notifiers are called only if the target value
  is now different.

pm_qos_update_requirement(param_id, name, new_target_value):

  Will search the list identified by the param_id for the named list element
  and then update its target value, calling the notification tree if the
  aggregated target is changed.  with that name is already registered.

pm_qos_remove_requirement(param_id, name):

  Will search the identified list for the named element and remove it, after
  removal it will update the aggregate target and call the notification tree
  if the target was changed as a result of removing the named requirement.

>From user mode:

  Only processes can register a pm_qos requirement.  To provide for
  automatic cleanup for process the interface requires the process to register
  its parameter requirements in the following way:

  To register the default pm_qos target for the specific parameter, the
  process must open one of /dev/[cpu_dma_latency, network_latency,
  network_throughput]

  As long as the device node is held open that process has a registered
  requirement on the parameter.  The name of the requirement is
  "process_<PID>" derived from the current->pid from within the open system
  call.

  To change the requested target value the process needs to write a s32
  value to the open device node.  This translates to a
  pm_qos_update_requirement call.

  To remove the user mode request for a target value simply close the device
  node.

[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: fix build again]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: mark gross <mgross@linux.intel.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Adam Belay <abelay@novell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 09:44:22 -08:00