If RCU priority boosting is to be meaningful, callback invocation must
be boosted in addition to preempted RCU readers. Otherwise, in presence
of CPU real-time threads, the grace period ends, but the callbacks don't
get invoked. If the callbacks don't get invoked, the associated memory
doesn't get freed, so the system is still subject to OOM.
But it is not reasonable to priority-boost RCU_SOFTIRQ, so this commit
moves the callback invocations to a kthread, which can be boosted easily.
Also add comments and properly synchronized all accesses to
rcu_cpu_kthread_task, as suggested by Lai Jiangshan.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Combine the current TREE_PREEMPT_RCU ->blocked_tasks[] lists in the
rcu_node structure into a single ->blkd_tasks list with ->gp_tasks
and ->exp_tasks tail pointers. This is in preparation for RCU priority
boosting, which will add a third dimension to the combinatorial explosion
in the ->blocked_tasks[] case, but simply a third pointer in the new
->blkd_tasks case.
Also update documentation to reflect blocked_tasks[] merge
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Commit d09b62d fixed grace-period synchronization, but left some smp_mb()
invocations in rcu_process_callbacks() that are no longer needed, but
sheer paranoia prevented them from being removed. This commit removes
them and provides a proof of correctness in their absence. It also adds
a memory barrier to rcu_report_qs_rsp() immediately before the update to
rsp->completed in order to handle the theoretical possibility that the
compiler or CPU might move massive quantities of code into a lock-based
critical section. This also proves that the sheer paranoia was not
entirely unjustified, at least from a theoretical point of view.
In addition, the old dyntick-idle synchronization depended on the fact
that grace periods were many milliseconds in duration, so that it could
be assumed that no dyntick-idle CPU could reorder a memory reference
across an entire grace period. Unfortunately for this design, the
addition of expedited grace periods breaks this assumption, which has
the unfortunate side-effect of requiring atomic operations in the
functions that track dyntick-idle state for RCU. (There is some hope
that the algorithms used in user-level RCU might be applied here, but
some work is required to handle the NMIs that user-space applications
can happily ignore. For the short term, better safe than sorry.)
This proof assumes that neither compiler nor CPU will allow a lock
acquisition and release to be reordered, as doing so can result in
deadlock. The proof is as follows:
1. A given CPU declares a quiescent state under the protection of
its leaf rcu_node's lock.
2. If there is more than one level of rcu_node hierarchy, the
last CPU to declare a quiescent state will also acquire the
->lock of the next rcu_node up in the hierarchy, but only
after releasing the lower level's lock. The acquisition of this
lock clearly cannot occur prior to the acquisition of the leaf
node's lock.
3. Step 2 repeats until we reach the root rcu_node structure.
Please note again that only one lock is held at a time through
this process. The acquisition of the root rcu_node's ->lock
must occur after the release of that of the leaf rcu_node.
4. At this point, we set the ->completed field in the rcu_state
structure in rcu_report_qs_rsp(). However, if the rcu_node
hierarchy contains only one rcu_node, then in theory the code
preceding the quiescent state could leak into the critical
section. We therefore precede the update of ->completed with a
memory barrier. All CPUs will therefore agree that any updates
preceding any report of a quiescent state will have happened
before the update of ->completed.
5. Regardless of whether a new grace period is needed, rcu_start_gp()
will propagate the new value of ->completed to all of the leaf
rcu_node structures, under the protection of each rcu_node's ->lock.
If a new grace period is needed immediately, this propagation
will occur in the same critical section that ->completed was
set in, but courtesy of the memory barrier in #4 above, is still
seen to follow any pre-quiescent-state activity.
6. When a given CPU invokes __rcu_process_gp_end(), it becomes
aware of the end of the old grace period and therefore makes
any RCU callbacks that were waiting on that grace period eligible
for invocation.
If this CPU is the same one that detected the end of the grace
period, and if there is but a single rcu_node in the hierarchy,
we will still be in the single critical section. In this case,
the memory barrier in step #4 guarantees that all callbacks will
be seen to execute after each CPU's quiescent state.
On the other hand, if this is a different CPU, it will acquire
the leaf rcu_node's ->lock, and will again be serialized after
each CPU's quiescent state for the old grace period.
On the strength of this proof, this commit therefore removes the memory
barriers from rcu_process_callbacks() and adds one to rcu_report_qs_rsp().
The effect is to reduce the number of memory barriers by one and to
reduce the frequency of execution from about once per scheduling tick
per CPU to once per grace period.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The RCU CPU stall warnings can now be controlled using the
rcu_cpu_stall_suppress boot-time parameter or via the same parameter
from sysfs. There is therefore no longer any reason to have
kernel config parameters for this feature. This commit therefore
removes the RCU_CPU_STALL_DETECTOR and RCU_CPU_STALL_DETECTOR_RUNNABLE
kernel config parameters. The RCU_CPU_STALL_TIMEOUT parameter remains
to allow the timeout to be tuned and the RCU_CPU_STALL_VERBOSE parameter
remains to allow task-stall information to be suppressed if desired.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* 'fixes-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: fix deadlock in worker_maybe_bind_and_lock()
workqueue: Document debugging tricks
Fix up trivial spelling conflict in kernel/workqueue.c
Recent Xeon processor thermal sensors are supported by the coretemp
driver and not the adm1021 driver. Only one old generation of Xeon
processors (the first Netburst ones) are supported by the adm1021
driver.
Reported-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
The lm90 driver's attribute update interval is configurable.
Reflect this information in the driver documentation.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This patch adds support for ADT7461A and NCT1008 to the lm90 driver.
Both chips have identical functionality and report the same manufacturing ID
and device ID values.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Since 569b846d ("memcg: coalesce uncharge during unmap/truncate"), we do
batched (delayed) uncharge at truncation/unmap. And since cdec2e42(memcg:
coalesce charging via percpu storage), we have percpu cache for
res_counter.
These changes improved performance of memory cgroup very much, but made
res_counter->usage usually have a bigger value than the actual value of
memory usage. So, *.usage_in_bytes, which show res_counter->usage, are
not desirable for precise values of memory(and swap) usage anymore.
Instead of removing these files completely(because we cannot know
res_counter->usage without them), this patch updates the meaning of those
files.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6: (42 commits)
[media] media: vb2: correct queue initialization order
[media] media: vb2: fix incorrect v4l2_buffer->flags handling
[media] s5p-fimc: Add support for the buffer timestamps and sequence
[media] s5p-fimc: Fix bytesperline and plane payload setup
[media] s5p-fimc: Do not allow changing format after REQBUFS
[media] s5p-fimc: Fix FIMC3 pixel limits on Exynos4
[media] tda18271: update tda18271c2_rf_cal as per NXP's rev.04 datasheet
[media] tda18271: update tda18271_rf_band as per NXP's rev.04 datasheet
[media] tda18271: fix bad calculation of main post divider byte
[media] tda18271: prog_cal and prog_tab variables should be s32, not u8
[media] tda18271: fix calculation bug in tda18271_rf_tracking_filters_init
[media] omap3isp: queue: Don't corrupt buf->npages when get_user_pages() fails
[media] v4l: Don't register media entities for subdev device nodes
[media] omap3isp: Don't increment node entity use count when poweron fails
[media] omap3isp: lane shifter support
[media] omap3isp: ccdc: support Y10/12, 8-bit bayer fmts
[media] media: add missing 8-bit bayer formats and Y12
[media] v4l: add V4L2_PIX_FMT_Y12 format
cx23885: Fix stv0367 Kconfig dependency
[media] omap3isp: Use isp xclk defines
...
Fix up trivial conflict (spelink errurs) in drivers/media/video/omap3isp/isp.c
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
ALSA: hda - Fix unused warnings when !SND_HDA_NEEDS_RESUME
ALSA: hda - Add a fix-up for Acer dmic with ALC271x codec
ASoC: add a module alias to the FSI driver
ALSA: emu10k1 - Fix "Music" controls to "Synth" controls in documents
ARM: s3c2440: gta02; Register dfbmcs320 device for BT audio interface
ASoC: codecs: JZ4740: Fix OOPS
ASoC: Fix output PGA enabling in wm_hubs CODECs
ASoC: sn95031: decorate function with __devexit_p()
ASoC: SAMSUNG: Fix the inverted clocks handling for pcm driver
ASoC: sst_platform: Fix lock acquring
ASoC: fsi: driver safely remove for against irq
ASoC: fsi: modify vague PM control on probe
ASoC: fsi: take care in failing case of dai register
MAINTAINERS: Update Samsung ASoC maintainer's id
ASoC: WM8903: HP and Line out PGA/mixer DAPM fixes
ASoC: Set left channel volume update bits for WM8994
ASoC: fix config error path
ASoC: check channel mismatch between cpu_dai and codec_dai
ASoC: Tegra: Suspend/resume support
linux/Documentation/md.txt is missing description for sync_min and
sync_max entries.
This patch adds description for sync_min and sync_max entries.
Signed-off-by: Roman Ovchinnikov <coolthecold@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
MAX34440 and MAX34441 have their own driver, thus there should be explicit
documentation instead of mentioning the chips in the generic PMBus driver
documentation.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Tom Grennan <tom.grennan@ericsson.com>
MAX16064 has its own driver, thus should have its own documentation instead of
being mentioned in the generic PMBus driver documentation.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Tom Grennan <tom.grennan@ericsson.com>
MAX8688 has its own driver, thus should have its own documentation instead of
being mentioned in the generic PMBus driver documentation.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Tom Grennan <tom.grennan@ericsson.com>
tempererature may sound interesting, but temperature is still preferred.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
When writing hardware monitoring drivers, there are some common pitfalls which
keep coming up in code reviews. This patch provides a document describing all
those pitfalls and how to avoid them.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
8-bit SGBRG and SRGGB media bus formats are missing, as well as the
12-bit grey format. Add them.
Signed-off-by: Michael Jones <michael.jones@matrix-vision.de>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Y12 is a grey-scale format with a depth of 12 bits per pixel stored in
16-bit words.
Signed-off-by: Michael Jones <michael.jones@matrix-vision.de>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: xen-kbdfront - fix mouse getting stuck after save/restore
Input: estimate number of events per packet
Input: evdev - indicate buffer overrun with SYN_DROPPED
Input: document event types and codes and their intended use
Input: add KEY_IMAGES specifically for AL Image Browser
Input: twl4030_keypad - fix potential NULL dereference in twl4030_kp_probe()
Input: h3600_ts - fix error handling at connect
Input: twl4030_keypad - avoid potential NULL-pointer dereference
Fix a couple of typos and clarify a formula in sh_mobile_ceu driver
documentation.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add a new EV_SYN code, SYN_DROPPED, to inform the client when input
events have been dropped from the evdev input buffer due to a
buffer overrun. The client should use this event as a hint to
reset its state or ignore all following events until the next
packet begins.
Signed-off-by: Jeff Brown <jeffbrown@android.com>
[dtor@mail.ru: Implement Henrik's suggestion and drop old events in
case of overflow.]
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit adds the file Documentation/input/event-codes.txt.
Acked-by: Henrik Rydberg <rydberg@euromail.se>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
Signed-off-by: Chris Bagwell <chris@cnpbagwell.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mjg59/platform-drivers-x86:
thinkpad-acpi fails to load with newer Thinkpad X201s BIOS
acer-wmi: Fix capitalisation of GUID in module alias
sony-laptop: keyboard backlight fixes
sony-laptop: only show the handles sysfs file in debug mode
samsung-laptop: set backlight type
staging: samsung-laptop has moved to platform/x86
samsung-laptop: Samsung R410P backlight driver
samsung-laptop: add support for N230 model
platform-drivers: x86: pmic: Restore the dropped buslock/unlock
sony-laptop: fix early NULL pointer dereference
msi-laptop: fix config-dependent build error
eeepc-wmi: add keys found on EeePC 1215T
asus-wmi: swap input name and phys
asus-laptop: remove removed features from feature-removal-schedule.txt
leds: move leds-class documentation under the leds/ subdir.
Add also a leds/00-INDEX file describing the files under leds/
Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Acked-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix some minor typos:
* informations => information
* there own => their own
* these => this
Signed-off-by: Sylvestre Ledru <sylvestre.ledru@scilab.org>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a little more info for some of the panic-related kernel parameters.
Fix "oops=panic" to fit in 80 columns.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Besides x86 and arm, kmemleak now supports powerpc, sparc, sh,
microblaze and tile.
Signed-off-by: Daniel Baluta <dbaluta@ixiacom.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is not obvious how to debug run-away workers.
These are some tips given by Tejun on lkml.
Signed-off-by: Florian Mickler <florian@mickler.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Correct all function names pertaining to load balancing and explain
shortly how load balancing is performed.
Signed-off-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1301241433-3790-1-git-send-email-bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This adds the samsung-laptop driver to the kernel. It now supports
all known Samsung laptops that use the SABI interface.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
New Asus notebooks are using a WMI device similar to
the one used in Eee PCs. Since we don't want to load
eeepc-wmi module on Asus notebooks, and we want to
keep the eeepc-wmi module for backward compatibility,
this patch introduce a new module, named asus-wmi, that
will be used by eeepc-wmi and the new Asus Notebook WMI
Driver.
eeepc-wmi's input device strings (device name and phys)
are kept, but rfkill and led names are changed (s/eeepc/asus/).
This should not break anything since rfkill are used by type or
index, not by name, and the eeepc::touchpad led wasn't working
correctly before 2.6.39 anyway.
Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
* 'for-2.6.39/drivers' of git://git.kernel.dk/linux-2.6-block: (122 commits)
cciss: fix lost command issue
drbd: need include for bitops functions declarations
Revert "cciss: Add missing allocation in scsi_cmd_stack_setup and corresponding deallocation"
cciss: fix missed command status value CMD_UNABORTABLE
cciss: remove unnecessary casts
cciss: Mask off error bits of c->busaddr in cmd_special_free when calling pci_free_consistent
cciss: Inform controller we are using 32-bit tags.
cciss: hoist tag masking out of loop
cciss: Add missing allocation in scsi_cmd_stack_setup and corresponding deallocation
cciss: export resettable host attribute
drbd: drop code present under #ifdef which is relevant to 2.6.28 and below
drbd: Fixed handling of read errors on a 'VerifyS' node
drbd: Fixed handling of read errors on a 'VerifyT' node
drbd: Implemented real timeout checking for request processing time
drbd: Remove unused function atodb_endio()
drbd: improve log message if received sector offset exceeds local capacity
drbd: kill dead code
drbd: don't BUG_ON, if bio_add_page of a single page to an empty bio fails
drbd: Removed left over, now wrong comments
drbd: serialize admin requests for new verify run with pending bitmap io
...
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
hwmon: (f71882fg) Add support for the F71889A
hwmon: (f71882fg) Add support for the F81865F
hwmon: (f71882fg) Document all supported devices
hwmon: (f71882fg) Per-chip fan/temperature input count tables
hwmon: (f71882fg) Secure chip property definition arrays
Fix fsl_rio.c kernel-doc warning: no exported symbols as
requested by !E are found:
Warning(arch/powerpc/sysdev/fsl_rio.c): no structured comments found
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
DocBook/v4l/ no longer has any *.png files, so the 'cp' command fails,
breaking the build. Drop the *.png cp.
cp: cannot stat `linux-2.6.38-git18/Documentation/DocBook/v4l/*.png': No such file or directory
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
