05 Jun, 2014
1 commit
-
Signed-off-by: Fabian Frederick
Cc: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 Mar, 2014
1 commit
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We must use smp_call_function_single(.wait=1) for the
irq_cpu_stop_queue_work() to ensure the queueing is actually done under
stop_cpus_lock. Without this we could have dropped the lock by the time
we do the queueing and get the race we tried to fix.Fixes: 7053ea1a34fa ("stop_machine: Fix race between stop_two_cpus() and stop_cpus()")
Signed-off-by: Peter Zijlstra
Cc: Prarit Bhargava
Cc: Rik van Riel
Cc: Mel Gorman
Cc: Christoph Hellwig
Cc: Andrew Morton
Link: http://lkml.kernel.org/r/20140228123905.GK3104@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar
11 Nov, 2013
1 commit
-
There is a race between stop_two_cpus, and the global stop_cpus.
It is possible for two CPUs to get their stopper functions queued
"backwards" from one another, resulting in the stopper threads
getting stuck, and the system hanging. This can happen because
queuing up stoppers is not synchronized.This patch adds synchronization between stop_cpus (a rare operation),
and stop_two_cpus.Reported-and-Tested-by: Prarit Bhargava
Signed-off-by: Rik van Riel
Signed-off-by: Peter Zijlstra
Acked-by: Mel Gorman
Link: http://lkml.kernel.org/r/20131101104146.03d1e043@annuminas.surriel.com
Signed-off-by: Ingo Molnar
16 Oct, 2013
1 commit
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Remove get_online_cpus() usage from the scheduler; there's 4 sites that
use it:- sched_init_smp(); where its completely superfluous since we're in
'early' boot and there simply cannot be any hotplugging.- sched_getaffinity(); we already take a raw spinlock to protect the
task cpus_allowed mask, this disables preemption and therefore
also stabilizes cpu_online_mask as that's modified using
stop_machine. However switch to active mask for symmetry with
sched_setaffinity()/set_cpus_allowed_ptr(). We guarantee active
mask stability by inserting sync_rcu/sched() into _cpu_down.- sched_setaffinity(); we don't appear to need get_online_cpus()
either, there's two sites where hotplug appears relevant:
* cpuset_cpus_allowed(); for the !cpuset case we use possible_mask,
for the cpuset case we hold task_lock, which is a spinlock and
thus for mainline disables preemption (might cause pain on RT).
* set_cpus_allowed_ptr(); Holds all scheduler locks and thus has
preemption properly disabled; also it already deals with hotplug
races explicitly where it releases them.- migrate_swap(); we can make stop_two_cpus() do the heavy lifting for
us with a little trickery. By adding a sync_sched/rcu() after the
CPU_DOWN_PREPARE notifier we can provide preempt/rcu guarantees for
cpu_active_mask. Use these to validate that both our cpus are active
when queueing the stop work before we queue the stop_machine works
for take_cpu_down().Signed-off-by: Peter Zijlstra
Cc: "Srivatsa S. Bhat"
Cc: Paul McKenney
Cc: Mel Gorman
Cc: Rik van Riel
Cc: Srikar Dronamraju
Cc: Andrea Arcangeli
Cc: Johannes Weiner
Cc: Linus Torvalds
Cc: Andrew Morton
Cc: Steven Rostedt
Cc: Oleg Nesterov
Link: http://lkml.kernel.org/r/20131011123820.GV3081@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar
09 Oct, 2013
1 commit
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Introduce stop_two_cpus() in order to allow controlled swapping of two
tasks. It repurposes the stop_machine() state machine but only stops
the two cpus which we can do with on-stack structures and avoid
machine wide synchronization issues.The ordering of CPUs is important to avoid deadlocks. If unordered then
two cpus calling stop_two_cpus on each other simultaneously would attempt
to queue in the opposite order on each CPU causing an AB-BA style deadlock.
By always having the lowest number CPU doing the queueing of works, we can
guarantee that works are always queued in the same order, and deadlocks
are avoided.Signed-off-by: Peter Zijlstra
[ Implemented deadlock avoidance. ]
Signed-off-by: Rik van Riel
Cc: Andrea Arcangeli
Cc: Johannes Weiner
Cc: Srikar Dronamraju
Signed-off-by: Mel Gorman
Link: http://lkml.kernel.org/r/1381141781-10992-38-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar
27 Feb, 2013
1 commit
-
commit 14e568e78 (stop_machine: Use smpboot threads) introduced the
following regression:Before this commit the stopper enabled bit was set in the online
notifier.CPU0 CPU1
cpu_up
cpu online
hotplug_notifier(ONLINE)
stopper(CPU1)->enabled = true;
...
stop_machine()The conversion to smpboot threads moved the enablement to the wakeup
path of the parked thread. The majority of users seem to have the
following working order:CPU0 CPU1
cpu_up
cpu online
unpark_threads()
wakeup(stopper[CPU1])
....
stopper thread runs
stopper(CPU1)->enabled = true;
stop_machine()But Konrad and Sander have observed:
CPU0 CPU1
cpu_up
cpu online
unpark_threads()
wakeup(stopper[CPU1])
....
stop_machine()
stopper thread runs
stopper(CPU1)->enabled = true;Now the stop machinery kicks CPU0 into the stop loop, where it gets
stuck forever because the queue code saw stopper(CPU1)->enabled ==
false, so CPU0 waits for CPU1 to enter stomp_machine, but the CPU1
stopper work got discarded due to enabled == false.Add a pre_unpark function to the smpboot thread descriptor and call it
before waking the thread.This fixes the problem at hand, but the stop_machine code should be
more robust. The stopper->enabled flag smells fishy at best.Thanks to Konrad for going through a loop of debug patches and
providing the information to decode this issue.Reported-and-tested-by: Konrad Rzeszutek Wilk
Reported-and-tested-by: Sander Eikelenboom
Cc: Srivatsa S. Bhat
Cc: Rusty Russell
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1302261843240.22263@ionos
Signed-off-by: Thomas Gleixner
14 Feb, 2013
2 commits
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Use the smpboot thread infrastructure. Mark the stopper thread
selfparking and park it after it has finished the take_cpu_down()
work.Signed-off-by: Thomas Gleixner
Cc: Peter Zijlstra
Cc: Rusty Russell
Cc: Paul McKenney
Cc: Srivatsa S. Bhat
Cc: Arjan van de Veen
Cc: Paul Turner
Cc: Richard Weinberger
Cc: Magnus Damm
Link: http://lkml.kernel.org/r/20130131120741.686315164@linutronix.de
Signed-off-by: Thomas Gleixner -
To allow the stopper thread being managed by the smpboot thread
infrastructure separate out the task storage from the stopper data
structure.Signed-off-by: Thomas Gleixner
Cc: Peter Zijlstra
Cc: Rusty Russell
Cc: Paul McKenney
Cc: Srivatsa S. Bhat
Cc: Arjan van de Veen
Cc: Paul Turner
Cc: Richard Weinberger
Cc: Magnus Damm
Link: http://lkml.kernel.org/r/20130131120741.626690384@linutronix.de
Signed-off-by: Thomas Gleixner
07 Nov, 2011
1 commit
-
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
Revert "tracing: Include module.h in define_trace.h"
irq: don't put module.h into irq.h for tracking irqgen modules.
bluetooth: macroize two small inlines to avoid module.h
ip_vs.h: fix implicit use of module_get/module_put from module.h
nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
include: replace linux/module.h with "struct module" wherever possible
include: convert various register fcns to macros to avoid include chaining
crypto.h: remove unused crypto_tfm_alg_modname() inline
uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
pm_runtime.h: explicitly requires notifier.h
linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
miscdevice.h: fix up implicit use of lists and types
stop_machine.h: fix implicit use of smp.h for smp_processor_id
of: fix implicit use of errno.h in include/linux/of.h
of_platform.h: delete needless include
acpi: remove module.h include from platform/aclinux.h
miscdevice.h: delete unnecessary inclusion of module.h
device_cgroup.h: delete needless include
net: sch_generic remove redundant use of
net: inet_timewait_sock doesnt need
...Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in
- drivers/media/dvb/frontends/dibx000_common.c
- drivers/media/video/{mt9m111.c,ov6650.c}
- drivers/mfd/ab3550-core.c
- include/linux/dmaengine.h
01 Nov, 2011
1 commit
-
Make stop_machine() safe to call early in boot, before SMP has been set
up, by simply calling the callback function directly if there's only one
CPU online.[ Fixes from AKPM:
- add comment
- local_irq_flags, not save_flags
- also call hard_irq_disable() for systems which need itTejun suggested using an explicit flag rather than just looking at
the online cpu count. ]Cc: Tejun Heo
Acked-by: Rusty Russell
Cc: Peter Zijlstra
Cc: H. Peter Anvin
Cc: Ingo Molnar
Cc: Steven Rostedt
Acked-by: Tejun Heo
Cc: Konrad Rzeszutek Wilk
Signed-off-by: Jeremy Fitzhardinge
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
31 Oct, 2011
1 commit
-
The changed files were only including linux/module.h for the
EXPORT_SYMBOL infrastructure, and nothing else. Revector them
onto the isolated export header for faster compile times.Nothing to see here but a whole lot of instances of:
-#include
+#includeThis commit is only changing the kernel dir; next targets
will probably be mm, fs, the arch dirs, etc.Signed-off-by: Paul Gortmaker
27 Jul, 2011
1 commit
-
This allows us to move duplicated code in
(atomic_inc_not_zero() for now) toSigned-off-by: Arun Sharma
Reviewed-by: Eric Dumazet
Cc: Ingo Molnar
Cc: David Miller
Cc: Eric Dumazet
Acked-by: Mike Frysinger
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
28 Jun, 2011
4 commits
-
MTRR rendezvous sequence is not implemened using stop_machine() before, as this
gets called both from the process context aswell as the cpu online paths
(where the cpu has not come online and the interrupts are disabled etc).Now that we have a new stop_machine_from_inactive_cpu() API, use it for
rendezvous during mtrr init of a logical processor that is coming online.For the rest (runtime MTRR modification, system boot, resume paths), use
stop_machine() to implement the rendezvous sequence. This will consolidate and
cleanup the code.Signed-off-by: Suresh Siddha
Link: http://lkml.kernel.org/r/20110623182057.076997177@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: H. Peter Anvin -
Currently, mtrr wants stop_machine functionality while a CPU is being
brought up. As stop_machine() requires the calling CPU to be active,
mtrr implements its own stop_machine using stop_one_cpu() on each
online CPU. This doesn't only unnecessarily duplicate complex logic
but also introduces a possibility of deadlock when it races against
the generic stop_machine().This patch implements stop_machine_from_inactive_cpu() to serve such
use cases. Its functionality is basically the same as stop_machine();
however, it should be called from a CPU which isn't active and doesn't
depend on working scheduling on the calling CPU.This is achieved by using busy loops for synchronization and
open-coding stop_cpus queuing and waiting with direct invocation of
fn() for local CPU inbetween.Signed-off-by: Tejun Heo
Link: http://lkml.kernel.org/r/20110623182056.982526827@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Suresh Siddha
Cc: Ingo Molnar
Cc: Andrew Morton
Cc: Linus Torvalds
Cc: Peter Zijlstra
Signed-off-by: H. Peter Anvin -
Refactor the queuing part of the stop cpus work from __stop_cpus() into
queue_stop_cpus_work().The reorganization is to help future improvements to stop_machine()
and doesn't introduce any behavior difference.Signed-off-by: Tejun Heo
Link: http://lkml.kernel.org/r/20110623182056.897818337@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Suresh Siddha
Cc: Ingo Molnar
Cc: Andrew Morton
Cc: Linus Torvalds
Cc: Peter Zijlstra
Signed-off-by: H. Peter Anvin -
MTRR rendezvous sequence using stop_one_cpu_nowait() can potentially
happen in parallel with another system wide rendezvous using
stop_machine(). This can lead to deadlock (The order in which
works are queued can be different on different cpu's. Some cpu's
will be running the first rendezvous handler and others will be running
the second rendezvous handler. Each set waiting for the other set to join
for the system wide rendezvous, leading to a deadlock).MTRR rendezvous sequence is not implemented using stop_machine() as this
gets called both from the process context aswell as the cpu online paths
(where the cpu has not come online and the interrupts are disabled etc).
stop_machine() works with only online cpus.For now, take the stop_machine mutex in the MTRR rendezvous sequence that
gets called from an online cpu (here we are in the process context
and can potentially sleep while taking the mutex). And the MTRR rendezvous
that gets triggered during cpu online doesn't need to take this stop_machine
lock (as the stop_machine() already ensures that there is no cpu hotplug
going on in parallel by doing get_online_cpus())TBD: Pursue a cleaner solution of extending the stop_machine()
infrastructure to handle the case where the calling cpu is
still not online and use this for MTRR rendezvous sequence.fixes: https://bugzilla.novell.com/show_bug.cgi?id=672008
Reported-by: Vadim Kotelnikov
Signed-off-by: Suresh Siddha
Link: http://lkml.kernel.org/r/20110623182056.807230326@sbsiddha-MOBL3.sc.intel.com
Cc: stable@kernel.org # 2.6.35+, backport a week or two after this gets more testing in mainline
Signed-off-by: H. Peter Anvin
23 Mar, 2011
1 commit
-
ksoftirqd, kworker, migration, and pktgend kthreads can be created with
kthread_create_on_node(), to get proper NUMA affinities for their stack and
task_struct.Signed-off-by: Eric Dumazet
Acked-by: David S. Miller
Reviewed-by: Andi Kleen
Acked-by: Rusty Russell
Acked-by: Tejun Heo
Cc: Tony Luck
Cc: Fenghua Yu
Cc: David Howells
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
27 Oct, 2010
2 commits
-
In commit e6bde73b07edeb703d4c89c1daabc09c303de11f ("cpu-hotplug: return
better errno on cpu hotplug failure"), the cpu notifier can return an
encapsulated errno value.This converts the cpu notifier to return an encapsulated errno value for
stop_machine().Signed-off-by: Akinobu Mita
Cc: Rusty Russell
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
kernel/stop_machine.c: In function `cpu_stopper_thread':
kernel/stop_machine.c:265: warning: unused variable `ksym_buf'ksym_buf[] is unused if WARN_ON() is a no-op.
Signed-off-by: Rakib Mullick
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Oct, 2010
1 commit
-
In order to separate the stop/migrate work thread from the SCHED_FIFO
implementation, create a special class for it that is of higher priority than
SCHED_FIFO itself.This currently solves a problem where cpu-hotplug consumes so much cpu-time
that the SCHED_FIFO class gets throttled, but has the bandwidth replenishment
timer pending on the now dead cpu.It is also required for when we add the planned deadline scheduling class above
SCHED_FIFO, as the stop/migrate thread still needs to transcent those tasks.Tested-by: Heiko Carstens
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar
10 Aug, 2010
1 commit
-
Reorder elements in structure cpu_stopper to remove alignment padding on
64 bit builds, this shrinks its size from 40 to 32 bytes saving 8 bytes
per cpu.Signed-off-by: Richard Kennedy
Acked-by: Tejun Heo
Cc: Peter Zijlstra
Cc: Ingo Molnar
Cc: Rusty Russell
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
31 May, 2010
1 commit
-
Problem: In a stress test where some heavy tests were running along with
regular CPU offlining and onlining, a hang was observed. The system seems
to be hung at a point where migration_call() tries to kill the
migration_thread of the dying CPU, which just got moved to the current
CPU. This migration thread does not get a chance to run (and die) since
rt_throttled is set to 1 on current, and it doesn't get cleared as the
hrtimer which is supposed to reset the rt bandwidth
(sched_rt_period_timer) is tied to the CPU which we just marked dead!Solution: This patch pushes the killing of migration thread to
"CPU_POST_DEAD" event. By then all the timers (including
sched_rt_period_timer) should have got migrated (along with other
callbacks).Signed-off-by: Amit Arora
Signed-off-by: Gautham R Shenoy
Acked-by: Tejun Heo
Signed-off-by: Peter Zijlstra
Cc: Thomas Gleixner
LKML-Reference:
Signed-off-by: Ingo Molnar
18 May, 2010
1 commit
-
This addresses the following compiler warning:
kernel/stop_machine.c: In function 'cpu_stop_cpu_callback':
kernel/stop_machine.c:297: warning: unused variable 'work'Cc: Tejun Heo
Cc: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar
08 May, 2010
1 commit
-
When !CONFIG_SMP, cpu_stop functions weren't defined at all which
could lead to build failures if UP code uses cpu_stop facility. Add
dummy cpu_stop implementation for UP. The waiting variants execute
the work function directly with preempt disabled and
stop_one_cpu_nowait() schedules a workqueue work.Makefile and ifdefs around stop_machine implementation are updated to
accomodate CONFIG_SMP && !CONFIG_STOP_MACHINE case.Signed-off-by: Tejun Heo
Reported-by: Ingo Molnar
07 May, 2010
3 commits
-
Currently migration_thread is serving three purposes - migration
pusher, context to execute active_load_balance() and forced context
switcher for expedited RCU synchronize_sched. All three roles are
hardcoded into migration_thread() and determining which job is
scheduled is slightly messy.This patch kills migration_thread and replaces all three uses with
cpu_stop. The three different roles of migration_thread() are
splitted into three separate cpu_stop callbacks -
migration_cpu_stop(), active_load_balance_cpu_stop() and
synchronize_sched_expedited_cpu_stop() - and each use case now simply
asks cpu_stop to execute the callback as necessary.synchronize_sched_expedited() was implemented with private
preallocated resources and custom multi-cpu queueing and waiting
logic, both of which are provided by cpu_stop.
synchronize_sched_expedited_count is made atomic and all other shared
resources along with the mutex are dropped.synchronize_sched_expedited() also implemented a check to detect cases
where not all the callback got executed on their assigned cpus and
fall back to synchronize_sched(). If called with cpu hotplug blocked,
cpu_stop already guarantees that and the condition cannot happen;
otherwise, stop_machine() would break. However, this patch preserves
the paranoid check using a cpumask to record on which cpus the stopper
ran so that it can serve as a bisection point if something actually
goes wrong theree.Because the internal execution state is no longer visible,
rcu_expedited_torture_stats() is removed.This patch also renames cpu_stop threads to from "stopper/%d" to
"migration/%d". The names of these threads ultimately don't matter
and there's no reason to make unnecessary userland visible changes.With this patch applied, stop_machine() and sched now share the same
resources. stop_machine() is faster without wasting any resources and
sched migration users are much cleaner.Signed-off-by: Tejun Heo
Acked-by: Peter Zijlstra
Cc: Ingo Molnar
Cc: Dipankar Sarma
Cc: Josh Triplett
Cc: Paul E. McKenney
Cc: Oleg Nesterov
Cc: Dimitri Sivanich -
Reimplement stop_machine using cpu_stop. As cpu stoppers are
guaranteed to be available for all online cpus,
stop_machine_create/destroy() are no longer necessary and removed.With resource management and synchronization handled by cpu_stop, the
new implementation is much simpler. Asking the cpu_stop to execute
the stop_cpu() state machine on all online cpus with cpu hotplug
disabled is enough.stop_machine itself doesn't need to manage any global resources
anymore, so all per-instance information is rolled into struct
stop_machine_data and the mutex and all static data variables are
removed.The previous implementation created and destroyed RT workqueues as
necessary which made stop_machine() calls highly expensive on very
large machines. According to Dimitri Sivanich, preventing the dynamic
creation/destruction makes booting faster more than twice on very
large machines. cpu_stop resources are preallocated for all online
cpus and should have the same effect.Signed-off-by: Tejun Heo
Acked-by: Rusty Russell
Acked-by: Peter Zijlstra
Cc: Oleg Nesterov
Cc: Dimitri Sivanich -
Implement a simplistic per-cpu maximum priority cpu monopolization
mechanism. A non-sleeping callback can be scheduled to run on one or
multiple cpus with maximum priority monopolozing those cpus. This is
primarily to replace and unify RT workqueue usage in stop_machine and
scheduler migration_thread which currently is serving multiple
purposes.Four functions are provided - stop_one_cpu(), stop_one_cpu_nowait(),
stop_cpus() and try_stop_cpus().This is to allow clean sharing of resources among stop_cpu and all the
migration thread users. One stopper thread per cpu is created which
is currently named "stopper/CPU". This will eventually replace the
migration thread and take on its name.* This facility was originally named cpuhog and lived in separate
files but Peter Zijlstra nacked the name and thus got renamed to
cpu_stop and moved into stop_machine.c.* Better reporting of preemption leak as per Peter's suggestion.
Signed-off-by: Tejun Heo
Acked-by: Peter Zijlstra
Cc: Oleg Nesterov
Cc: Dimitri Sivanich
17 Feb, 2010
1 commit
-
Add __percpu sparse annotations to core subsystems.
These annotations are to make sparse consider percpu variables to be
in a different address space and warn if accessed without going
through percpu accessors. This patch doesn't affect normal builds.Signed-off-by: Tejun Heo
Reviewed-by: Christoph Lameter
Acked-by: Paul E. McKenney
Cc: Jens Axboe
Cc: linux-mm@kvack.org
Cc: Rusty Russell
Cc: Dipankar Sarma
Cc: Peter Zijlstra
Cc: Andrew Morton
Cc: Eric Biederman
30 Mar, 2009
1 commit
-
Impact: cleanup
struct cpumask is nicer, and we use it to make where we've made code
safe for CONFIG_CPUMASK_OFFSTACK=y.Signed-off-by: Rusty Russell
20 Feb, 2009
1 commit
-
Impact: cleanup
There are two allocated per-cpu accessor macros with almost identical
spelling. The original and far more popular is per_cpu_ptr (44
files), so change over the other 4 files.tj: kill percpu_ptr() and update UP too
Signed-off-by: Rusty Russell
Cc: mingo@redhat.com
Cc: lenb@kernel.org
Cc: cpufreq@vger.kernel.org
Signed-off-by: Tejun Heo
05 Jan, 2009
1 commit
-
Introduce stop_machine_create/destroy. With this interface subsystems
that need a non-failing stop_machine environment can create the
stop_machine machine threads before actually calling stop_machine.
When the threads aren't needed anymore they can be killed with
stop_machine_destroy again.When stop_machine gets called and the threads aren't present they
will be created and destroyed automatically. This restores the old
behaviour of stop_machine.This patch also converts cpu hotplug to the new interface since it
is special: cpu_down calls __stop_machine instead of stop_machine.
However the kstop threads will only be created when stop_machine
gets called.Changing the code so that the threads would be created automatically
on __stop_machine is currently not possible: when __stop_machine gets
called we hold cpu_add_remove_lock, which is the same lock that
create_rt_workqueue would take. So the workqueue needs to be created
before the cpu hotplug code locks cpu_add_remove_lock.Signed-off-by: Heiko Carstens
Signed-off-by: Rusty Russell
01 Jan, 2009
1 commit
-
Impact: Reduce stack usage, use new cpumask API.
Mainly changing cpumask_t to 'struct cpumask' and similar simple API
conversion. Two conversions worth mentioning:1) we use cpumask_any_but to avoid a temporary in kernel/softlockup.c,
2) Use cpumask_var_t in taskstats_user_cmd().Signed-off-by: Rusty Russell
Signed-off-by: Mike Travis
Cc: Balbir Singh
Cc: Ingo Molnar
17 Nov, 2008
1 commit
-
Bug #11989: Suspend failure on NForce4-based boards due to chanes in
stop_machineWe should not access active.fnret outside the lock; in theory the next
stop_machine could overwrite it.Signed-off-by: Rusty Russell
Tested-by: "Rafael J. Wysocki"
Signed-off-by: Linus Torvalds
26 Oct, 2008
1 commit
-
This reverts commit a802dd0eb5fc97a50cf1abb1f788a8f6cc5db635 by moving
the call to init_workqueues() back where it belongs - after SMP has been
initialized.It also moves stop_machine_init() - which needs workqueues - to a later
phase using a core_initcall() instead of early_initcall(). That should
satisfy all ordering requirements, and was apparently the reason why
init_workqueues() was moved to be too early.Cc: Heiko Carstens
Cc: Rusty Russell
Signed-off-by: Linus Torvalds
22 Oct, 2008
2 commits
-
Using |= for updating a value which might be updated on several cpus
concurrently will not always work since we need to make sure that the
update happens atomically.
To fix this just use a write if the called function returns an error
code on a cpu. We end up writing the error code of an arbitrary cpu
if multiple ones fail but that should be sufficient.Signed-off-by: Heiko Carstens
Signed-off-by: Rusty Russell -
Convert stop_machine to a workqueue based approach. Instead of using kernel
threads for stop_machine we now use a an rt workqueue to synchronize all
cpus.
This has the advantage that all needed per cpu threads are already created
when stop_machine gets called. And therefore a call to stop_machine won't
fail anymore. This is needed for s390 which needs a mechanism to synchronize
all cpus without allocating any memory.
As Rusty pointed out free_module() needs a non-failing stop_machine interface
as well.As a side effect the stop_machine code gets simplified.
Signed-off-by: Heiko Carstens
Signed-off-by: Rusty Russell
12 Aug, 2008
1 commit
-
Signed-off-by: Li Zefan
Signed-off-by: Rusty Russell
28 Jul, 2008
3 commits
-
Instead of a "cpu" arg with magic values NR_CPUS (any cpu) and ~0 (all
cpus), pass a cpumask_t. Allow NULL for the common case (where we
don't care which CPU the function is run on): temporary cpumask_t's
are usually considered bad for stack space.This deprecates stop_machine_run, to be removed soon when all the
callers are dead.Signed-off-by: Rusty Russell
-
stop_machine creates a kthread which creates kernel threads. We can
create those threads directly and simplify things a little. Some care
must be taken with CPU hotunplug, which has special needs, but that code
seems more robust than it was in the past.Signed-off-by: Rusty Russell
Acked-by: Christian Borntraeger -
-allow stop_mahcine_run() to call a function on all cpus. Calling
stop_machine_run() with a 'ALL_CPUS' invokes this new behavior.
stop_machine_run() proceeds as normal until the calling cpu has
invoked 'fn'. Then, we tell all the other cpus to call 'fn'.Signed-off-by: Jason Baron
Signed-off-by: Mathieu Desnoyers
Signed-off-by: Rusty Russell
CC: Adrian Bunk
CC: Andi Kleen
CC: Alexey Dobriyan
CC: Christoph Hellwig
CC: mingo@elte.hu
CC: akpm@osdl.org
