There are some dependencies between devices (in particular, between
EHCI USB controllers and their OHCI/UHCI siblings) which are not
reflected by the structure of the device tree. With synchronous
suspend and resume these dependencies are taken into accout
automatically, because the devices in question are always registered
in the right order, but to meet these constraints with asynchronous
suspend and resume the drivers of these devices will need to use
dpm_wait() in their suspend/resume routines, so introduce a helper
function allowing them to do that.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
It has been shown by testing that total device resume time can be
reduced significantly (by as much as 50% or more) if the async
threads executing some devices' resume routines are all started
before the main resume thread starts to handle the "synchronous"
devices.
This is a consequence of the fact that the slowest devices tend to be
located at the end of dpm_list, so their resume routines are started
very late. Consequently, they have to wait for all the preceding
"synchronous" devices before their resume routines can be started
by the main resume thread, even if they are "asynchronous". By
starting their async threads upfront we effectively move those
devices towards the beginning of dpm_list, without breaking their
ordering with respect to their parents and children. As a result,
their resume routines are started much earlier and we are able to
save much more device resume time this way.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Add configuration switch CONFIG_PM_ADVANCED_DEBUG for compiling in
extra PM debugging/testing code allowing one to access some
PM-related attributes of devices from the user space via sysfs.
If CONFIG_PM_ADVANCED_DEBUG is set, add sysfs attribute power/async
for every device allowing the user space to access the device's
power.async_suspend flag and modify it, if desired.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Add sysfs attribute /sys/power/pm_async allowing the user space to
disable/enable asynchronous suspend/resume of devices.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Theoretically, the total time of system sleep transitions (suspend
to RAM, hibernation) can be reduced by running suspend and resume
callbacks of device drivers in parallel with each other. However,
there are dependencies between devices such that we're not allowed
to suspend the parent of a device before suspending the device
itself. Analogously, we're not allowed to resume a device before
resuming its parent.
The most straightforward way to take these dependencies into accout
is to start the async threads used for suspending and resuming
devices at the core level, so that async_schedule() is called for
each suspend and resume callback supposed to be executed
asynchronously.
For this purpose, introduce a new device flag, power.async_suspend,
used to mark the devices whose suspend and resume callbacks are to be
executed asynchronously (ie. in parallel with the main suspend/resume
thread and possibly in parallel with each other) and helper function
device_enable_async_suspend() allowing one to set power.async_suspend
for given device (power.async_suspend is unset by default for all
devices). For each device with the power.async_suspend flag set the
PM core will use async_schedule() to execute its suspend and resume
callbacks.
The async threads started for different devices as a result of
calling async_schedule() are synchronized with each other and with
the main suspend/resume thread with the help of completions, in the
following way:
(1) There is a completion, power.completion, for each device object.
(2) Each device's completion is reset before calling async_schedule()
for the device or, in the case of devices with the
power.async_suspend flags unset, before executing the device's
suspend and resume callbacks.
(3) During suspend, right before running the bus type, device type
and device class suspend callbacks for the device, the PM core
waits for the completions of all the device's children to be
completed.
(4) During resume, right before running the bus type, device type and
device class resume callbacks for the device, the PM core waits
for the completion of the device's parent to be completed.
(5) The PM core completes power.completion for each device right
after the bus type, device type and device class suspend (or
resume) callbacks executed for the device have returned.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Add new device sysfs attribute, power/control, allowing the user
space to block the run-time power management of the devices. If this
attribute is set to "on", the driver of the device won't be able to power
manage it at run time (without breaking the rules) and the device will
always be in the full power state (except when the entire system goes
into a sleep state).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
On Mon, Jan 18, 2010 at 05:26:20PM +0530, Sachin Sant wrote:
> Hello Heiko,
>
> Today while trying to boot next-20100118 i came across
> the following Oops :
>
> Brought up 4 CPUs
> Unable to handle kernel pointer dereference at virtual kernel address 0000000000
> 543000
> Oops: 0004 #1 SMP
> Modules linked in:
> CPU: 0 Not tainted 2.6.33-rc4-autotest-next-20100118-5-default #1
> Process swapper (pid: 1, task: 00000000fd792038, ksp: 00000000fd797a30)
> Krnl PSW : 0704200180000000 00000000001eb0b8 (shmem_parse_options+0xc0/0x328)
> R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 EA:3
> Krnl GPRS: 000000000054388a 000000000000003d 0000000000543836 000000000000003d
> 0000000000000000 0000000000483f28 0000000000536112 00000000fd797d00
> 00000000fd4ba100 0000000000000100 0000000000483978 0000000000543832
> 0000000000000000 0000000000465958 00000000001eb0b0 00000000fd797c58
> Krnl Code: 00000000001eb0aa: c0e5000994f1 brasl %r14,31da8c
> 00000000001eb0b0: b9020022 ltgr %r2,%r2
> 00000000001eb0b4: a784010b brc 8,1eb2ca
> >00000000001eb0b8: 92002000 mvi 0(%r2),0
> 00000000001eb0bc: a7080000 lhi %r0,0
> 00000000001eb0c0: 41902001 la %r9,1(%r2)
> 00000000001eb0c4: b9040016 lgr %r1,%r6
> 00000000001eb0c8: b904002b lgr %r2,%r11
> Call Trace:
> (<00000000fd797c50> 0xfd797c50)
> <00000000001eb5da> shmem_fill_super+0x13a/0x25c
> <0000000000228cfa> get_sb_single+0xbe/0xdc
> <000000000034ffc0> dev_get_sb+0x2c/0x38
> <000000000066c602> devtmpfs_init+0x46/0xc0
> <000000000066c53e> driver_init+0x22/0x60
> <000000000064d40a> kernel_init+0x24e/0x3d0
> <000000000010a7ea> kernel_thread_starter+0x6/0xc
> <000000000010a7e4> kernel_thread_starter+0x0/0xc
>
> I never tried to boot a kernel with DEVTMPFS enabled on a s390 box.
> So am wondering if this is supported or not ? If you think this
> is supported i will send a mail to community on this.
There is nothing arch specific to devtmpfs. This part crashes because the
kernel tries to modify the data read-only section which is write protected
on s390.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The function prototype mismatches in call stack:
[<ffffffff81494268>] print_block_size+0x58/0x60
[<ffffffff81487e3f>] sysdev_class_show+0x1f/0x30
[<ffffffff811d629b>] sysfs_read_file+0xcb/0x1f0
[<ffffffff81176328>] vfs_read+0xc8/0x180
Due to prototype mismatch, print_block_size() will sprintf() into
*attribute instead of *buf, hence user space will read the initial
zeros from *buf:
$ hexdump /sys/devices/system/memory/block_size_bytes
0000000 0000 0000 0000 0000
0000008
After patch:
cat /sys/devices/system/memory/block_size_bytes
0x8000000
This complements commits c29af9636 and 4a0b2b4dbe.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: "Zheng, Shaohui" <shaohui.zheng@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Warning(drivers/base/power/main.c:453): No description found for parameter 'dev'
Warning(drivers/base/power/main.c:453): No description found for parameter 'cb'
Warning(drivers/base/power/main.c:719): No description found for parameter 'dev'
Warning(drivers/base/power/main.c:719): No description found for parameter 'state'
Warning(drivers/base/power/main.c:719): No description found for parameter 'cb'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This allows MFD's to register/bind drivers for their sub devices while
still being compiled as a module.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
priv is drv->p. So only free drv->p after we've finished using priv.
Found using a static code analysis tool
Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
If device_add() is called with a device which does not have dev->p set
up, then device_private_init() is called. If that succeeds, then the
error variable is set to 0. Now if the dev_name(dev) check further
down fails, then device_add() correctly terminates, but returns 0.
That of course lets the driver progress. If later another driver uses
this half set up device as parent then device_add() of the child
device explodes and renders sysfs completely unusable.
Set the error to -EINVAL if dev_name() check fails.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: "Hans J. Koch" <hjk@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Many struct driver_attribute descriptors are purely read-only
structures, and there's no need to change them. Therefore make
the promise not to, which will let those descriptors be put in
a ro section.
Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Many struct bin_attribute descriptors are purely read-only
structures, and there's no need to change them. Therefore
make the promise not to, which will let those descriptors
be put in a ro section.
Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Most device_attributes are const, and are begging to be
put in a ro section. However, the create and remove
file interfaces were failing to propagate the const promise
which the only functions they call offer.
Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
devtmpfs has a rw_lock dirlock which serializes delete_path and
create_path.
This code was obviously never tested with the usual set of debugging
facilities enabled. In the dirlock held sections the code calls:
- vfs functions which take mutexes
- kmalloc(, GFP_KERNEL)
In both code pathes the might sleep warning triggers and spams dmesg.
Convert the rw_lock to a mutex. There is no reason why this needs to
be a rwlock.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
PM: Runtime PM documentation update
PM / Runtime: Use device type and device class callbacks
PM: Use pm_runtime_put_sync in system resume
PM: Measure device suspend and resume times
PM: Make the initcall_debug style timing for suspend/resume complete
The power management of some devices is handled through device types
and device classes rather than through bus types. Since these
devices may also benefit from using the run-time power management
core, extend it so that the device type and device class run-time PM
callbacks can be taken into consideration by it if the bus type
callback is not defined.
Update the run-time PM core documentation to reflect this change.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This patch (as1317) fixes a bug in the PM core. When a device is
resumed following a system sleep, the core decrements the device's
runtime PM usage counter but doesn't issue an idle notification if the
counter reaches 0. This could prevent an otherwise unused device from
being runtime-suspended again after the system sleep.
The fix is to call pm_runtime_put_sync() instead of
pm_runtime_put_noidle().
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Memory balloon drivers can allocate a large amount of memory which is not
movable but could be freed to accomodate memory hotplug remove.
Prior to calling the memory hotplug notifier chain the memory in the
pageblock is isolated. Currently, if the migrate type is not
MIGRATE_MOVABLE the isolation will not proceed, causing the memory removal
for that page range to fail.
Rather than failing pageblock isolation if the migrateteype is not
MIGRATE_MOVABLE, this patch checks if all of the pages in the pageblock,
and not on the LRU, are owned by a registered balloon driver (or other
entity) using a notifier chain. If all of the non-movable pages are owned
by a balloon, they can be freed later through the memory notifier chain
and the range can still be isolated in set_migratetype_isolate().
Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Brian King <brking@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Gerald Schaefer <geralds@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
