Commit Graph

26706 Commits

Author SHA1 Message Date
Rafael J. Wysocki
9696cc9007 Merge branch 'pm-qos' into pm-for-linus
* pm-qos:
  PM / QoS: Update Documentation for the pm_qos and dev_pm_qos frameworks
  PM / QoS: Add function dev_pm_qos_read_value() (v3)
  PM QoS: Add global notification mechanism for device constraints
  PM QoS: Implement per-device PM QoS constraints
  PM QoS: Generalize and export constraints management code
  PM QoS: Reorganize data structs
  PM QoS: Code reorganization
  PM QoS: Minor clean-ups
  PM QoS: Move and rename the implementation files
2011-10-07 23:17:07 +02:00
Rafael J. Wysocki
c28b56b1d4 Merge branch 'pm-domains' into pm-for-linus
* pm-domains:
  PM / Domains: Split device PM domain data into base and need_restore
  ARM: mach-shmobile: sh7372 sleep warning fixes
  ARM: mach-shmobile: sh7372 A3SM support
  ARM: mach-shmobile: sh7372 generic suspend/resume support
  PM / Domains: Preliminary support for devices with power.irq_safe set
  PM: Move clock-related definitions and headers to separate file
  PM / Domains: Use power.sybsys_data to reduce overhead
  PM: Reference counting of power.subsys_data
  PM: Introduce struct pm_subsys_data
  ARM / shmobile: Make A3RV be a subdomain of A4LC on SH7372
  PM / Domains: Rename argument of pm_genpd_add_subdomain()
  PM / Domains: Rename GPD_STATE_WAIT_PARENT to GPD_STATE_WAIT_MASTER
  PM / Domains: Allow generic PM domains to have multiple masters
  PM / Domains: Add "wait for parent" status for generic PM domains
  PM / Domains: Make pm_genpd_poweron() always survive parent removal
  PM / Domains: Do not take parent locks to modify subdomain counters
  PM / Domains: Implement subdomain counters as atomic fields
2011-10-07 23:17:02 +02:00
Rafael J. Wysocki
d727b60659 Merge branch 'pm-runtime' into pm-for-linus
* pm-runtime:
  PM / Tracing: build rpm-traces.c only if CONFIG_PM_RUNTIME is set
  PM / Runtime: Replace dev_dbg() with trace_rpm_*()
  PM / Runtime: Introduce trace points for tracing rpm_* functions
  PM / Runtime: Don't run callbacks under lock for power.irq_safe set
  USB: Add wakeup info to debugging messages
  PM / Runtime: pm_runtime_idle() can be called in atomic context
  PM / Runtime: Add macro to test for runtime PM events
  PM / Runtime: Add might_sleep() to runtime PM functions
2011-10-07 23:16:55 +02:00
David S. Miller
88c5100c28 Merge branch 'master' of github.com:davem330/net
Conflicts:
	net/batman-adv/soft-interface.c
2011-10-07 13:38:43 -04:00
Linus Torvalds
6367f1775e Merge branch 'for-linus' of http://people.redhat.com/agk/git/linux-dm
* 'for-linus' of http://people.redhat.com/agk/git/linux-dm:
  dm crypt: always disable discard_zeroes_data
  dm: raid fix write_mostly arg validation
  dm table: avoid crash if integrity profile changes
  dm: flakey fix corrupt_bio_byte error path
2011-10-06 08:31:47 -07:00
Joerg Roedel
a240f76165 perf, core: Introduce attrs to count in either host or guest mode
The two new attributes exclude_guest and exclude_host can
bes used by user-space to tell the kernel to setup
performance counter to either only count while the CPU is in
guest or in host mode.

An additional check is also introduced to make sure
user-space does not try to exclude guest and host mode from
counting.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1317816084-18026-2-git-send-email-gleb@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-06 13:00:28 +02:00
Ingo Molnar
9243a169ac Merge commit 'v3.1-rc9' into sched/core
Merge reason: pick up latest fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-06 12:43:35 +02:00
Grant Likely
9514a56753 Merge branch 'for-grant' of git://git.jdl.com/software/linux-3.0 into devicetree/next 2011-10-05 10:52:27 -06:00
David Henningsson
7c2f8e4009 ALSA: jack - Add "Line In" input jack constants
Similar to Line Out, these constants form the base for future
patches enabling input jack reporting for Line in jacks.

Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2011-10-05 17:22:04 +02:00
Timur Tabi
c4e5a02327 drivers/video: fsl-diu-fb: only DIU modes 0 and 1 are supported
The Freescale DIU video controller supports five video "modes", but only
the first two are used by the driver.  The other three are special modes
that don't make sense for a framebuffer driver.  Therefore, there's no
point in keeping a global variable that indicates which mode we're
supposed to use.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
2011-10-05 01:10:12 +00:00
Timur Tabi
b715f9f04c drivers/video: fsl-diu-fb: move some definitions out of the header file
Move several macros and structures from the Freescale DIU driver's header
file into the source file, because they're only used by that file.  Also
delete a few unused macros.

The diu and diu_ad structures cannot be moved because they're being used
by the MPC5121 platform file.  A future patch eliminate the need for
the platform file to access these structs, so they'll be moved also.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
2011-10-05 01:10:12 +00:00
Timur Tabi
36b0b1d415 drivers/video: fsl-diu-fb: fix some ioctls
Use the _IOx macros to define the ioctl commands, instead of hard-coded
numbers.  Unfortunately, the original definitions of MFB_SET_PIXFMT and
MFB_GET_PIXFMT used the wrong value for the size, so these macros have
new values now.  To avoid breaking binary compatibility with older
applications, we retain support for the original values, but the driver
displays a warning message if they're used.

Also remove the FBIOGET_GWINFO and FBIOPUT_GWINFO ioctls.  FBIOPUT_GWINFO
was never implemented, and FBIOGET_GWINFO was never used by any
application.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
2011-10-05 01:06:55 +00:00
Jamie Iles
4cd7f7a311 dt: add helper to read 64-bit integers
Add a helper similar to of_property_read_u32() that handles 64-bit
integers.

v2/v3: constify device node and property name parameters.

Cc: Grant Likely <grant.likely@secretlab.ca>
Reviewed-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2011-10-04 16:59:53 -06:00
Jamie Iles
a1330228f9 dw_apb_timer: constify clocksource name
The clocksource name should be const for correctness.

Cc: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-10-04 13:08:18 -07:00
Rafael J. Wysocki
1a9a91525d PM / QoS: Add function dev_pm_qos_read_value() (v3)
To read the current PM QoS value for a given device we need to
make sure that the device's power.constraints object won't be
removed while we're doing that.  For this reason, put the
operation under dev->power.lock and acquire the lock
around the initialization and removal of power.constraints.

Moreover, since we're using the value of power.constraints to
determine whether or not the object is present, the
power.constraints_state field isn't necessary any more and may be
removed.  However, dev_pm_qos_add_request() needs to check if the
device is being removed from the system before allocating a new
PM QoS constraints object for it, so make it use the
power.power_state field of struct device for this purpose.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-10-04 21:54:26 +02:00
Linus Torvalds
8a04b45367 Merge git://github.com/davem330/net
* git://github.com/davem330/net:
  pch_gbe: Fixed the issue on which a network freezes
  pch_gbe: Fixed the issue on which PC was frozen when link was downed.
  make PACKET_STATISTICS getsockopt report consistently between ring and non-ring
  net: xen-netback: correctly restart Tx after a VM restore/migrate
  bonding: properly stop queuing work when requested
  can bcm: fix incomplete tx_setup fix
  RDSRDMA: Fix cleanup of rds_iw_mr_pool
  net: Documentation: Fix type of variables
  ibmveth: Fix oops on request_irq failure
  ipv6: nullify ipv6_ac_list and ipv6_fl_list when creating new socket
  cxgb4: Fix EEH on IBM P7IOC
  can bcm: fix tx_setup off-by-one errors
  MAINTAINERS: tehuti: Alexander Indenbaum's address bounces
  dp83640: reduce driver noise
  ptp: fix L2 event message recognition
2011-10-04 10:37:06 -07:00
Jon Mason
5f39e6705f PCI: Disable MPS configuration by default
Add the ability to disable PCI-E MPS turning and using the BIOS
configured MPS defaults.  Due to the number of issues recently
discovered on some x86 chipsets, make this the default behavior.

Also, add the option for peer to peer DMA MPS configuration.  Peer to
peer DMA is outside the scope of this patch, but MPS configuration could
prevent it from working by having the MPS on one root port different
than the MPS on another.  To work around this, simply make the system
wide MPS the smallest possible value (128B).

Signed-off-by: Jon Mason <mason@myri.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-04 09:52:28 -07:00
Benoit Cousson
4fcd15a032 of: Add helpers to get one string in multiple strings property
Add of_property_read_string_index and of_property_count_strings
to retrieve one string inside a property that will contains
severals strings.

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Kevin Hilman <khilman@ti.com>
2011-10-04 09:52:23 -07:00
Mark Brown
81204c84ca ASoC: Add WM1811 support
The WM1811 is mostly register compatible with the WM8994 and WM8958,
providing a high performance audio hub CODEC in a small form factor
suitable for ultra compact system designs.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-10-04 11:59:46 +01:00
Mark Brown
b1f43bf3a5 mfd: Add WM1811 support
The WM1811 is mostly register compatible with the WM8994 and WM8958,
providing a high performance audio hub CODEC in a small form factor
suitable for ultra compact system designs.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
2011-10-04 11:59:02 +01:00
Peter Zijlstra
f0f1d32f93 llist: Remove cpu_relax() usage in cmpxchg loops
Initial benchmarks show they're a net loss:

 $ for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ; do echo performance > $i; done
 $ echo 4096 32000 64 128 > /proc/sys/kernel/sem
 $ ./sembench -t 2048 -w 1900 -o 0

Pre:

 run time 30 seconds 778936 worker burns per second
 run time 30 seconds 912190 worker burns per second
 run time 30 seconds 817506 worker burns per second
 run time 30 seconds 830870 worker burns per second
 run time 30 seconds 845056 worker burns per second

Post:

 run time 30 seconds 905920 worker burns per second
 run time 30 seconds 849046 worker burns per second
 run time 30 seconds 886286 worker burns per second
 run time 30 seconds 822320 worker burns per second
 run time 30 seconds 900283 worker burns per second

So about 4% faster. (!)

cpu_relax() stalls the pipeline, therefore, when used in a tight loop
it has the following benefits:

 - allows SMT siblings to have a go;
 - reduces pressure on the CPU interconnect.

However, cmpxchg loops are unfair and thus have unbounded completion
time, therefore we should avoid getting in such heavily contended
situations where the above benefits make any difference.

A typical cmpxchg loop should not go round more than a handfull of
times at worst, therefore adding extra delays just slows things down.

Since the llist primitives are new, there aren't any bad users yet,
and we should avoid growing them. Heavily contended sites should
generally be better off using the ticket locks for serialization since
they provide bounded completion times (fifo-fair over the cpus).

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1315836358.26517.43.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-04 12:44:03 +02:00
Peter Zijlstra
fa14ff4acc sched: Convert to struct llist
Use the generic llist primitives.

We had a private lockless list implementation in the scheduler in the wake-list
code, now that we have a generic llist implementation that provides all required
operations, switch to it.

This patch is not expected to change any behavior.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1315836353.26517.42.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-04 12:43:58 +02:00
Peter Zijlstra
924f8f5af3 llist: Add llist_next()
So we don't have to expose the struct list_node member.

Cc: Huang Ying <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1315836348.26517.41.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-04 12:43:53 +02:00
Huang Ying
38aaf8090d irq_work: Use llist in the struct irq_work logic
Use llist in irq_work instead of the lock-less linked list
implementation in irq_work to avoid the code duplication.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1315461646-1379-6-git-send-email-ying.huang@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-04 12:43:49 +02:00
Huang Ying
781f7fd916 llist: Return whether list is empty before adding in llist_add()
Extend the llist_add*() functions to return a success indicator, this
allows us in the scheduler code to send an IPI if the queue was empty.

( There's no effect on existing users, because the list_add_xxx() functions
  are inline, thus this will be optimized out by the compiler if not used
  by callers. )

Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1315461646-1379-5-git-send-email-ying.huang@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-04 12:43:44 +02:00
Huang Ying
a3127336b7 llist: Move cpu_relax() to after the cmpxchg()
If in llist_add()/etc. functions the first cmpxchg() call succeeds, it is
not necessary to use cpu_relax() before the cmpxchg(). So cpu_relax() in
a busy loop involving cmpxchg() should go after cmpxchg() instead of before
that.

This patch fixes this for all involved llist functions.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1315461646-1379-4-git-send-email-ying.huang@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-04 12:43:39 +02:00
Ingo Molnar
2c30245c65 llist: Remove the platform-dependent NMI checks
Remove the nmi() checks spread around the code. in_nmi() is not available
on every architecture and it's a pretty obscure and ugly check in any case.

Cc: Huang Ying <ying.huang@intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1315461646-1379-3-git-send-email-ying.huang@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-04 12:43:11 +02:00
Huang Ying
1230db8e15 llist: Make some llist functions inline
Because llist code will be used in performance critical scheduler
code path, make llist_add() and llist_del_all() inline to avoid
function calling overhead and related 'glue' overhead.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1315461646-1379-2-git-send-email-ying.huang@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-04 11:30:53 +02:00
Ingo Molnar
22f92bacbe Merge branch 'linus' into sched/core
Merge reason: pick up the latest fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-10-04 11:09:08 +02:00
Sangwook Lee
e209c5a7ed net:rfkill: add a gpio setup function into GPIO rfkill
Add a gpio setup function which gives a chance to set up
platform specific configuration such as pin multiplexing,
input/output direction at the runtime or booting time.

Signed-off-by: Sangwook Lee <sangwook.lee@linaro.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-10-03 15:19:19 -04:00
Vasily Averin
349d2895cc ipv4: NET_IPV4_ROUTE_GC_INTERVAL removal
removing obsoleted sysctl,
ip_rt_gc_interval variable no longer used since 2.6.38

Signed-off-by: Vasily Averin <vvs@sw.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-10-03 14:13:01 -04:00
Jiří Župka
96c131842a Repair wrong named definition aligned_u64
This repairs problem with compile library in userspace (libnl).

Signed-off-by: Jiří Župka <jzupka@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-10-03 14:03:48 -04:00
Eric Dumazet
b5c5693bb7 tcp: report ECN_SEEN in tcp_info
Allows ss command (iproute2) to display "ecnseen" if at least one packet
with ECT(0) or ECT(1) or ECN was received by this socket.

"ecn" means ECN was negotiated at session establishment (TCP level)

"ecnseen" means we received at least one packet with ECT fields set (IP
level)

ss -i
...
ESTAB      0      0   192.168.20.110:22  192.168.20.144:38016
ino:5950 sk:f178e400
	 mem:(r0,w0,f0,t0) ts sack ecn ecnseen bic wscale:7,8 rto:210
rtt:12.5/7.5 cwnd:10 send 9.3Mbps rcv_space:14480

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-10-03 14:01:21 -04:00
Marc Zyngier
1e7c5fd294 genirq: percpu: allow interrupt type to be set at enable time
As request_percpu_irq() doesn't allow for a percpu interrupt to have
its type configured (it is generally impossible to configure it on all
CPUs at once), add a 'type' argument to enable_percpu_irq().

This allows some low-level, board specific init code to be switched to
a generic API.

[ tglx: Added WARN_ON argument ]

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-10-03 15:35:27 +02:00
Marc Zyngier
31d9d9b6d8 genirq: Add support for per-cpu dev_id interrupts
The ARM GIC interrupt controller offers per CPU interrupts (PPIs),
which are usually used to connect local timers to each core. Each CPU
has its own private interface to the GIC, and only sees the PPIs that
are directly connect to it.

While these timers are separate devices and have a separate interrupt
line to a core, they all use the same IRQ number.

For these devices, request_irq() is not the right API as it assumes
that an IRQ number is visible by a number of CPUs (through the
affinity setting), but makes it very awkward to express that an IRQ
number can be handled by all CPUs, and yet be a different interrupt
line on each CPU, requiring a different dev_id cookie to be passed
back to the handler.

The *_percpu_irq() functions is designed to overcome these
limitations, by providing a per-cpu dev_id vector:

int request_percpu_irq(unsigned int irq, irq_handler_t handler,
		   const char *devname, void __percpu *percpu_dev_id);
void free_percpu_irq(unsigned int, void __percpu *);
int setup_percpu_irq(unsigned int irq, struct irqaction *new);
void remove_percpu_irq(unsigned int irq, struct irqaction *act);
void enable_percpu_irq(unsigned int irq);
void disable_percpu_irq(unsigned int irq);

The API has a number of limitations:
- no interrupt sharing
- no threading
- common handler across all the CPUs

Once the interrupt is requested using setup_percpu_irq() or
request_percpu_irq(), it must be enabled by each core that wishes its
local interrupt to be delivered.

Based on an initial patch by Thomas Gleixner.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1316793788-14500-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-10-03 15:35:26 +02:00
Wu Fengguang
9d823e8f6b writeback: per task dirty rate limit
Add two fields to task_struct.

1) account dirtied pages in the individual tasks, for accuracy
2) per-task balance_dirty_pages() call intervals, for flexibility

The balance_dirty_pages() call interval (ie. nr_dirtied_pause) will
scale near-sqrt to the safety gap between dirty pages and threshold.

The main problem of per-task nr_dirtied is, if 1k+ tasks start dirtying
pages at exactly the same time, each task will be assigned a large
initial nr_dirtied_pause, so that the dirty threshold will be exceeded
long before each task reached its nr_dirtied_pause and hence call
balance_dirty_pages().

The solution is to watch for the number of pages dirtied on each CPU in
between the calls into balance_dirty_pages(). If it exceeds ratelimit_pages
(3% dirty threshold), force call balance_dirty_pages() for a chance to
set bdi->dirty_exceeded. In normal situations, this safeguarding
condition is not expected to trigger at all.

On the sqrt in dirty_poll_interval():

It will serve as an initial guess when dirty pages are still in the
freerun area.

When dirty pages are floating inside the dirty control scope [freerun,
limit], a followup patch will use some refined dirty poll interval to
get the desired pause time.

   thresh-dirty (MB)    sqrt
		   1      16
		   2      22
		   4      32
		   8      45
		  16      64
		  32      90
		  64     128
		 128     181
		 256     256
		 512     362
		1024     512

The above table means, given 1MB (or 1GB) gap and the dd tasks polling
balance_dirty_pages() on every 16 (or 512) pages, the dirty limit won't
be exceeded as long as there are less than 16 (or 512) concurrent dd's.

So sqrt naturally leads to less overheads and more safe concurrent tasks
for large memory servers, which have large (thresh-freerun) gaps.

peter: keep the per-CPU ratelimit for safeguarding the 1k+ tasks case

CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Andrea Righi <andrea@betterlinux.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-10-03 21:08:57 +08:00
Wu Fengguang
7381131cbc writeback: stabilize bdi->dirty_ratelimit
There are some imperfections in balanced_dirty_ratelimit.

1) large fluctuations

The dirty_rate used for computing balanced_dirty_ratelimit is merely
averaged in the past 200ms (very small comparing to the 3s estimation
period for write_bw), which makes rather dispersed distribution of
balanced_dirty_ratelimit.

It's pretty hard to average out the singular points by increasing the
estimation period. Considering that the averaging technique will
introduce very undesirable time lags, I give it up totally. (btw, the 3s
write_bw averaging time lag is much more acceptable because its impact
is one-way and therefore won't lead to oscillations.)

The more practical way is filtering -- most singular
balanced_dirty_ratelimit points can be filtered out by remembering some
prev_balanced_rate and prev_prev_balanced_rate. However the more
reliable way is to guard balanced_dirty_ratelimit with task_ratelimit.

2) due to truncates and fs redirties, the (write_bw <=> dirty_rate)
match could become unbalanced, which may lead to large systematical
errors in balanced_dirty_ratelimit. The truncates, due to its possibly
bumpy nature, can hardly be compensated smoothly. So let's face it. When
some over-estimated balanced_dirty_ratelimit brings dirty_ratelimit
high, dirty pages will go higher than the setpoint. task_ratelimit will
in turn become lower than dirty_ratelimit.  So if we consider both
balanced_dirty_ratelimit and task_ratelimit and update dirty_ratelimit
only when they are on the same side of dirty_ratelimit, the systematical
errors in balanced_dirty_ratelimit won't be able to bring
dirty_ratelimit far away.

The balanced_dirty_ratelimit estimation may also be inaccurate near
@limit or @freerun, however is less an issue.

3) since we ultimately want to

- keep the fluctuations of task ratelimit as small as possible
- keep the dirty pages around the setpoint as long time as possible

the update policy used for (2) also serves the above goals nicely:
if for some reason the dirty pages are high (task_ratelimit < dirty_ratelimit),
and dirty_ratelimit is low (dirty_ratelimit < balanced_dirty_ratelimit),
there is no point to bring up dirty_ratelimit in a hurry only to hurt
both the above two goals.

So, we make use of task_ratelimit to limit the update of dirty_ratelimit
in two ways:

1) avoid changing dirty rate when it's against the position control target
   (the adjusted rate will slow down the progress of dirty pages going
   back to setpoint).

2) limit the step size. task_ratelimit is changing values step by step,
   leaving a consistent trace comparing to the randomly jumping
   balanced_dirty_ratelimit. task_ratelimit also has the nice smaller
   errors in stable state and typically larger errors when there are big
   errors in rate.  So it's a pretty good limiting factor for the step
   size of dirty_ratelimit.

Note that bdi->dirty_ratelimit is always tracking balanced_dirty_ratelimit.
task_ratelimit is merely used as a limiting factor.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-10-03 21:08:57 +08:00
Wu Fengguang
be3ffa2764 writeback: dirty rate control
It's all about bdi->dirty_ratelimit, which aims to be (write_bw / N)
when there are N dd tasks.

On write() syscall, use bdi->dirty_ratelimit
============================================

    balance_dirty_pages(pages_dirtied)
    {
        task_ratelimit = bdi->dirty_ratelimit * bdi_position_ratio();
        pause = pages_dirtied / task_ratelimit;
        sleep(pause);
    }

On every 200ms, update bdi->dirty_ratelimit
===========================================

    bdi_update_dirty_ratelimit()
    {
        task_ratelimit = bdi->dirty_ratelimit * bdi_position_ratio();
        balanced_dirty_ratelimit = task_ratelimit * write_bw / dirty_rate;
        bdi->dirty_ratelimit = balanced_dirty_ratelimit
    }

Estimation of balanced bdi->dirty_ratelimit
===========================================

balanced task_ratelimit
-----------------------

balance_dirty_pages() needs to throttle tasks dirtying pages such that
the total amount of dirty pages stays below the specified dirty limit in
order to avoid memory deadlocks. Furthermore we desire fairness in that
tasks get throttled proportionally to the amount of pages they dirty.

IOW we want to throttle tasks such that we match the dirty rate to the
writeout bandwidth, this yields a stable amount of dirty pages:

        dirty_rate == write_bw                                          (1)

The fairness requirement gives us:

        task_ratelimit = balanced_dirty_ratelimit
                       == write_bw / N                                  (2)

where N is the number of dd tasks.  We don't know N beforehand, but
still can estimate balanced_dirty_ratelimit within 200ms.

Start by throttling each dd task at rate

        task_ratelimit = task_ratelimit_0                               (3)
                         (any non-zero initial value is OK)

After 200ms, we measured

        dirty_rate = # of pages dirtied by all dd's / 200ms
        write_bw   = # of pages written to the disk / 200ms

For the aggressive dd dirtiers, the equality holds

        dirty_rate == N * task_rate
                   == N * task_ratelimit_0                              (4)
Or
        task_ratelimit_0 == dirty_rate / N                              (5)

Now we conclude that the balanced task ratelimit can be estimated by

                                                      write_bw
        balanced_dirty_ratelimit = task_ratelimit_0 * ----------        (6)
                                                      dirty_rate

Because with (4) and (5) we can get the desired equality (1):

                                                       write_bw
        balanced_dirty_ratelimit == (dirty_rate / N) * ----------
                                                       dirty_rate
                                 == write_bw / N

Then using the balanced task ratelimit we can compute task pause times like:

        task_pause = task->nr_dirtied / task_ratelimit

task_ratelimit with position control
------------------------------------

However, while the above gives us means of matching the dirty rate to
the writeout bandwidth, it at best provides us with a stable dirty page
count (assuming a static system). In order to control the dirty page
count such that it is high enough to provide performance, but does not
exceed the specified limit we need another control.

The dirty position control works by extending (2) to

        task_ratelimit = balanced_dirty_ratelimit * pos_ratio           (7)

where pos_ratio is a negative feedback function that subjects to

1) f(setpoint) = 1.0
2) df/dx < 0

That is, if the dirty pages are ABOVE the setpoint, we throttle each
task a bit more HEAVY than balanced_dirty_ratelimit, so that the dirty
pages are created less fast than they are cleaned, thus DROP to the
setpoints (and the reverse).

Based on (7) and the assumption that both dirty_ratelimit and pos_ratio
remains CONSTANT for the past 200ms, we get

        task_ratelimit_0 = balanced_dirty_ratelimit * pos_ratio         (8)

Putting (8) into (6), we get the formula used in
bdi_update_dirty_ratelimit():

                                                write_bw
        balanced_dirty_ratelimit *= pos_ratio * ----------              (9)
                                                dirty_rate

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-10-03 21:08:56 +08:00
Wu Fengguang
af6a311384 writeback: add bg_threshold parameter to __bdi_update_bandwidth()
No behavior change.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-10-03 21:08:56 +08:00
Wu Fengguang
c8e28ce049 writeback: account per-bdi accumulated dirtied pages
Introduce the BDI_DIRTIED counter. It will be used for estimating the
bdi's dirty bandwidth.

CC: Jan Kara <jack@suse.cz>
CC: Michael Rubin <mrubin@google.com>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-10-03 21:08:56 +08:00
Linus Walleij
b1e3be0647 clocksource: fixup ux500 build problems
Based on a patch from Arnd Bergmann this fixes up the build
problem of assigning a non-existing global when the ux500 PRCMU
timer is not linked in by passing its base address to the init
function. We also add a missing <linux/errno.h> inclusion and
staticize the dummy function.

Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2011-10-03 09:34:16 +02:00
Dan Williams
f6e67035a9 [SCSI] libsas,libata: fix ->change_queue_{depth|type} for sata devices
Pass queue_depth change requests to libata, and prevent queue_type
changes for ATA devices.

Otherwise:
1/ we do not honor the libata specific restrictions on the queue depth
2/ libsas drivers that do not set sdev->tagged_supported are unable to
   change the queue_depth of ata devices via sysfs

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2011-10-02 12:30:30 -05:00
MyungJoo Ham
ce26c5bb95 PM / devfreq: Add basic governors
Four cpufreq-like governors are provided as examples.

powersave: use the lowest frequency possible. The user (device) should
set the polling_ms as 0 because polling is useless for this governor.

performance: use the highest freqeuncy possible. The user (device)
should set the polling_ms as 0 because polling is useless for this
governor.

userspace: use the user specified frequency stored at
devfreq.user_set_freq. With sysfs support in the following patch, a user
may set the value with the sysfs interface.

simple_ondemand: simplified version of cpufreq's ondemand governor.

When a user updates OPP entries (enable/disable/add), OPP framework
automatically notifies devfreq to update operating frequency
accordingly. Thus, devfreq users (device drivers) do not need to update
devfreq manually with OPP entry updates or set polling_ms for powersave
, performance, userspace, or any other "static" governors.

Note that these are given only as basic examples for governors and any
devices with devfreq may implement their own governors with the drivers
and use them.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Mike Turquette <mturquette@ti.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-10-02 00:19:34 +02:00
MyungJoo Ham
a3c98b8b2e PM: Introduce devfreq: generic DVFS framework with device-specific OPPs
With OPPs, a device may have multiple operable frequency and voltage
sets. However, there can be multiple possible operable sets and a system
will need to choose one from them. In order to reduce the power
consumption (by reducing frequency and voltage) without affecting the
performance too much, a Dynamic Voltage and Frequency Scaling (DVFS)
scheme may be used.

This patch introduces the DVFS capability to non-CPU devices with OPPs.
DVFS is a techique whereby the frequency and supplied voltage of a
device is adjusted on-the-fly. DVFS usually sets the frequency as low
as possible with given conditions (such as QoS assurance) and adjusts
voltage according to the chosen frequency in order to reduce power
consumption and heat dissipation.

The generic DVFS for devices, devfreq, may appear quite similar with
/drivers/cpufreq.  However, cpufreq does not allow to have multiple
devices registered and is not suitable to have multiple heterogenous
devices with different (but simple) governors.

Normally, DVFS mechanism controls frequency based on the demand for
the device, and then, chooses voltage based on the chosen frequency.
devfreq also controls the frequency based on the governor's frequency
recommendation and let OPP pick up the pair of frequency and voltage
based on the recommended frequency. Then, the chosen OPP is passed to
device driver's "target" callback.

When PM QoS is going to be used with the devfreq device, the device
driver should enable OPPs that are appropriate with the current PM QoS
requests. In order to do so, the device driver may call opp_enable and
opp_disable at the notifier callback of PM QoS so that PM QoS's
update_target() call enables the appropriate OPPs. Note that at least
one of OPPs should be enabled at any time; be careful when there is a
transition.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Mike Turquette <mturquette@ti.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-10-02 00:19:15 +02:00
Linus Torvalds
f72a209a3e Merge branches 'irq-urgent-for-linus', 'x86-urgent-for-linus' and 'sched-urgent-for-linus' of git://tesla.tglx.de/git/linux-2.6-tip
* 'irq-urgent-for-linus' of git://tesla.tglx.de/git/linux-2.6-tip:
  irq: Fix check for already initialized irq_domain in irq_domain_add
  irq: Add declaration of irq_domain_simple_ops to irqdomain.h

* 'x86-urgent-for-linus' of git://tesla.tglx.de/git/linux-2.6-tip:
  x86/rtc: Don't recursively acquire rtc_lock

* 'sched-urgent-for-linus' of git://tesla.tglx.de/git/linux-2.6-tip:
  posix-cpu-timers: Cure SMP wobbles
  sched: Fix up wchan borkage
  sched/rt: Migrate equal priority tasks to available CPUs
2011-10-01 08:37:25 -07:00
MyungJoo Ham
03ca370fbf PM / OPP: Add OPP availability change notifier.
The patch enables to register notifier_block for an OPP-device in order
to get notified for any changes in the availability of OPPs of the
device. For example, if a new OPP is inserted or enable/disable status
of an OPP is changed, the notifier is executed.

This enables the usage of opp_add, opp_enable, and opp_disable to
directly take effect with any connected entities such as cpufreq or
devfreq.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Mike Turquette <mturquette@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-09-30 22:35:12 +02:00
Arik Nemtsov
07ba55d7f1 nl80211/mac80211: allow adding TDLS peers as stations
When adding a TDLS peer STA, mark it with a new flag in both nl80211 and
mac80211. Before adding a peer, make sure the wiphy supports TDLS and
our operating mode is appropriate (managed).

In addition, make sure all peers are removed on disassociation.

A TDLS peer is first added just before link setup is initiated. In later
setup stages we have more info about peer supported rates, capabilities,
etc. This info is reported via nl80211_set_station().

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Cc: Kalyan C Gaddam <chakkal@iit.edu>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-09-30 15:57:08 -04:00
Arik Nemtsov
dfe018bf99 mac80211: handle TDLS high-level commands and frames
Register and implement the TDLS cfg80211 callback functions.

Internally prepare and send TDLS management frames. We incorporate
local STA capabilities and supported rates with extra IEs given by
usermode. The resulting packet is either encapsulated in a data frame,
or assembled as an action frame. It is transmitted either directly or
through the AP, as mandated by the TDLS specification.

Declare support for the TDLS external setup wiphy capability. This
tells usermode to handle link setup and discovery on its own, and use the
kernel driver for sending TDLS mgmt packets.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Cc: Kalyan C Gaddam <chakkal@iit.edu>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-09-30 15:57:07 -04:00
Arik Nemtsov
109086ce0b nl80211: support sending TDLS commands/frames
Add support for sending high-level TDLS commands and TDLS frames via
NL80211_CMD_TDLS_OPER and NL80211_CMD_TDLS_MGMT, respectively. Add
appropriate cfg80211 callbacks for lower level drivers.

Add wiphy capability flags for TDLS support and advertise them via
nl80211.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Cc: Kalyan C Gaddam <chakkal@iit.edu>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-09-30 15:57:05 -04:00
John W. Linville
8e00f5fbb4 Merge branch 'master' of git://git.infradead.org/users/linville/wireless-next into for-davem
Conflicts:
	drivers/net/wireless/iwlwifi/iwl-pci.c
	drivers/net/wireless/wl12xx/main.c
2011-09-30 14:52:29 -04:00