There is a race between set_cpus_allowed() and move_task_off_dead_cpu().
__migrate_task() doesn't report any err code, so task can be left on its
runqueue if its cpus_allowed mask changed so that dest_cpu is not longer a
possible target. Also, chaning cpus_allowed mask requires rq->lock being
held.
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Acked-By: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Unless we expect to have more than 2G CPUs, there's no reason to have 'i'
as a long long here.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The relationship between INTERACTIVE_SLEEP and the ceiling is not perfect
and not explicit enough. The sleep boost is not supposed to be any larger
than without this code and the comment is not clear enough about what
exactly it does, just the reason it does it. Fix it.
There is a ceiling to the priority beyond which tasks that only ever sleep
for very long periods cannot surpass. Fix it.
Prevent the on-runqueue bonus logic from defeating the idle sleep logic.
Opportunity to micro-optimise.
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial report and lock contention fix from Chris Mason:
Recent benchmarks showed some performance regressions between 2.6.16 and
2.6.5. We tracked down one of the regressions to lock contention in
schedule heavy workloads (~70,000 context switches per second)
kernel/sched.c:dependent_sleeper() was responsible for most of the lock
contention, hammering on the run queue locks. The patch below is more of a
discussion point than a suggested fix (although it does reduce lock
contention significantly). The dependent_sleeper code looks very expensive
to me, especially for using a spinlock to bounce control between two
different siblings in the same cpu.
It is further optimized:
* perform dependent_sleeper check after next task is determined
* convert wake_sleeping_dependent to use trylock
* skip smt runqueue check if trylock fails
* optimize double_rq_lock now that smt nice is converted to trylock
* early exit in searching first SD_SHARE_CPUPOWER domain
* speedup fast path of dependent_sleeper
[akpm@osdl.org: cleanup]
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Chris Mason <mason@suse.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Replace the temp makefile hacks with proper CONFIG entries, which are also
added to Kconfig.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add current pin settings to gpio_dump() output. This adds the last 'word' to
the syslog lines, which displays the input and output values that the pin is
set to.
pc8736x_gpio.0: io00: 0x0044 TS OD PUE EDGE LO DEBOUNCE io:1/1
The 2 values may differ for a number of reasons:
1- the pin output circuitry is diaabled, (as the above 'TS' indicates)
2- it needs a pullup resistor to drive the attached circuit,
3- the external circuit needs a pullup so the open-drain has something
to pull-down
4- the pin is wired to Vcc or Ground
It might be appropriate to add a WARN for 2,3,4, since they could
damage the chip and/or circuit, esp if misconfig goes unnoticed.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Hmm. Im somewhat ambivalent about this patch, since with it, driver wont
build for vanilla 17 or older.
Its also only 1/2 of your suggestion - when I tried it, I was building against
vanilla 17, and asm/uaccess.h cause compilation failure. Looking back, Im
perplexed as to why linux/io.h didnt cause same failure ?!?
use linux/io.h rather than asm/io.h
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Replace spinlocks guarding gpio config ops with mutexes. This is a me-too
patch, and is justifiable insofar as mutexes have stricter semantics and
better debugging support, so are preferred where they are applicable.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a working gpio_current() to pc8736x_gpio.c (the previous implementation
just threw a dev_warn), and fix gpio_change() to use gpio_current() rather
than the incorrect (and temporary) gpio_get(). Initialize shadow-regs so this
all works.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use of dev_dbg() and friends is considered good practice. dev_dbg() needs a
struct device *devp, but nsc_gpio is only a helper module, so it doesnt
have/need its own. To provide devp to the user-modules (scx200 & pc8736x
_gpio), we add it to the vtable, and set it during init.
Also squeeze nsc_gpio_dump()'s format a little.
[ 199.259879] pc8736x_gpio.0: io09: 0x0044 TS OD PUE EDGE LO DEBOUNCE
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Adds platform-device to (just introduced) driver, and uses it to replace many
printks with dev_dbg() etc. This could trivially be merged into previous
patch, but this way matches better with the corresponding patch that does the
same change to scx200_gpio.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add the brand new pc8736x_gpio driver. This is mostly based upon
scx200_gpio.c, but the platform_dev is treated separately, since its fairly
big too.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Since the meaning of config-bits is the same for scx200 and pc8736x _gpios, we
can share a function to deliver this to user. Since it is called via the
vtable, its also completely replaceable. For now, we keep using printk...
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Now that the read(), write() file-ops are dispatching gpio-ops via the vtable,
they are generic, and can be moved 'verbatim' to the nsc_gpio common-support
module. After the move, various symbols are renamed to update 'scx200_' to
'nsc_', and headers are adjusted accordingly.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add the nsc_gpio common-support module as an empty shell. Next patch starts
the migration of the common gpio support routines.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Abstract the gpio operations into a new nsc_gpio_ops vtable.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Pull shadow-reg initialization into separate function now, rather than doing
it 2x later (scx200, pc8736x). When we revisit 2nd drvr below, it will be to
reimplement an init function, rather than another refactor.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a new driver command: 'v' which calls gpio_dump() on the pin. The output
goes to the log, like all other INFO messages in the original driver. Giving
the user control over the feedback they 'need' is construed to be a
user-friendly feature, and allows us (later) to dial down many INFO messages
to DEBUG log-level.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Shrink scx200_gpio_dump() to a single printk with ternary ops. The function
is still ifdef'd out, this is corrected in next patch, when it is actually
used.
The patch 'inadvertently' changed loglevel from DEBUG to INFO. This is Good,
because in next patch, its wired to a 'command' which the user can invoke when
they want. When they do so, its because they want INFO to support their
developement effort, and we want to give it to them without compiling a DEBUG
version of the driver.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Per kernel headers, device minor numbers are unsigned ints. Do the same in
this driver.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a platform-device to scx200_gpio, and use its struct device dev member
(ie: devp) in dev_dbg() once.
There are 2 alternatives here (Im soliciting guidance/commentary):
- use isa_device, if/when its added to the kernel.
- alter scx200.c to EXPORT_GPL its private devp so that both scx200_gpio,
and the (to be added) nsc_gpio module can use it. Since the available devp
is in 'grandparent', this seems like too much 'action at a distance'.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Adopt many modern 2.6 coding practices, ala LDD3, chapter 3. Changes are
limited to initialization calls from module init, ie: cdev_init, cdev_add,
*_chrdev_region, mkdev.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
GPIO SUPPORT FOR SCx200 & PC8736x
The patch-set reworks the 2.4 vintage scx200_gpio driver for modern 2.6, and
refactors GPIO support to reuse it in a new driver for the GPIO on PC-8736x
chips. Its handy for the Soekris.com net-4801, which has both chips.
These patches have been seen recently on Kernel-Mentors, and then
Kernel-Newbies ML, where Jesper Juhl kindly reviewed it. His feedback has
been incorporated. Thanks Jesper !
Its also gone to soekris-tech@soekris.com for possible testing by linux folks,
I've gotten 1 promise so far. Theyre mostly BSD folk over there, but we'll
see..
Device-file & Sysfs
The driver preserves the existing device-file interface, including the
write/cmd set, but adds v to 'view' the pin-settings & configs by inducing,
via gpio_dump(), a dev_info() call. Its a fairly crappy way to get status,
but it sticks to the syslog approach, conservatively.
Allowing users to voluntarily trigger logging is good, it gives them a
familiar way to confirm their app's control & use of the pins, and I've thus
reduced the pin-mode-updates from dev_info to dev_dbg.
I've recently bolted on a proto sysfs interface for both new drivers. Im not
including those patches here; they (the patch + doc-pre-patch) are still quite
raw (and unreviewed on KNML), and since they 'invent' a convention for GPIO, a
proper vetting is needed. Since this patchset is much bigger than my previous
ones, Id like to keep things simpler, and address it 1st, before bolting on
more stuff.
The driver-split
The Geode CPU and the PC-87366 Super-IO chip have GPIO units which share a
common pin-architecture (same pin features, with same bits controlling), but
with different addressing mechanics and port organizations.
The vintage driver expresses the pin capabilities with pin-mode commands
[OoPpTt],etc that change the pin configurations, and since the 2 chips share
pin-arch, we can reuse the read(), write() commands, once the implementation
is suitably adjusted.
The patchset adds a vtable: struct nsc_gpio_ops, to abstract the existing gpio
operations, then adjusts fileops.write() code to invoke operations via that
vtable. Driver specific open()s set private_data to the vtable so its
available for use by write().
The vtable gets the gpio_dump() too, since its user-friendly, and (could be
construed as) part of the current device-file interface. To support use of
dev_dbg() in write() & _dump(), the vtable gets a dev ptr too, set by both
scx200 & pc8736x _gpio drivers.
heres how the pins are presented in syslog:
[ 1890.176223] scx200_gpio.0: io00: 0x0044 TS OD PUE EDGE LO DEBOUNCE
[ 1890.287223] scx200_gpio.0: io01: 0x0003 OE PP PUD EDGE LO
nsc_gpio.c: new file is new home of several file-ops methods, which are
modified to get their vtable from filp->private_data, and use it where needed.
scx200_gpio.c: keeps some of its existing gpio routines, but now wires them up
via the vtable (they're invoked by nsc_gpio.c:nsc_gpio_write() thru this
vtable). A driver-spcific open() initializes filp->private_data with the
vtable.
Once the split is clean, and the scx200_gpio driver is working, we copy and
modify the function and variable names, and rework the access-method bodies
for the different addressing scheme.
Heres a working overview of the patchset:
# series file for GPIO
# Spring Cleaning
gpio-scx/patch.preclean # scripts/Lindent fixes, editor-ctrl comments
# API Modernization
gpio-scx/patch.api26 # what I learned from LDD3
gpio-scx/patch.platform-dev-2 # get pdev, support for dev_dbg()
gpio-scx/patch.unsigned-minor # fix to match std practice
# Debuggability
gpio-scx/patch.dump-diet # shrink gpio_dump()
gpio-scx/patch.viewpins # add new 'command' to call dump()
gpio-scx/patch.init-refactor # pull shadow-register init to sub
# Access-Abstraction (add vtable)
gpio-scx/patch.access-vtable # introduce nsg_gpio_ops vtable, w dump
gpio-scx/patch.vtable-calls # add & use the vtable in scx200_gpio
gpio-scx/patch.nscgpio-shell # add empty driver for common-fops
# move code under abstraction
gpio-scx/patch.migrate-fops # move file-ops methods from scx200_gpio
gpio-scx/patch.common-dump # mv scx200.c:scx200_gpio_dump() to nsc_gpio.c
gpio-scx/patch.add-pc8736x-gpio # add new driver, like old, w chip adapt
# gpio-scx/patch.add-DEBUG # enable all dev_dbg()s
# Cleanups
# finish printk -> dev_dbg() etc
gpio-scx/patch.pdev-pc8736x # new drvr needs pdev too,
gpio-scx/patch.devdbg-nscgpio # add device to 'vtable', use in dev_dbg()
# gpio-scx/patch.pin-config-view # another 'c' 'command'
# gpio-scx/quiet-getset # take out excess dbg stuff (pretty quiet
now)
gpio-scx/patch.shadow-current # imitate scx200_gpio's shadow regs in
pc87*
# post KMentors-post patches ..
gpio-scx/patch.mutexes # use mutexes for config-locks
gpio-scx/patch.viewpins-values # extend dump to obsolete separate 'c' cmd
gpio-scx/patch.kconfig # add stuff for kbuild
# TBC
# combine api26 with pdev, which is just one step.
# merge c&v commands to single do-all-fn
# delay viewpins, dump-diet should also un-ifdef it too.
diff.sys-gpio-rollup-1
This patch:
Removed editor format-control comments, and used scripts/Lindent to clean up
whitespace, then deleted the bogus chunks :-(
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
