Commit graph

39 commits

Author SHA1 Message Date
Thomas Gleixner
dc186ad741 workqueue: Add debugobjects support
Add debugobject support to track the life time of work_structs.

While at it, remove duplicate definition of
INIT_DELAYED_WORK_ON_STACK().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
2009-11-16 01:09:48 +09:00
Linus Torvalds
43046b6066 workqueue: add 'flush_delayed_work()' to run and wait for delayed work
It basically turns a delayed work into an immediate work, and then waits
for it to finish.
2009-10-14 09:16:42 -07:00
Dmitri Vorobiev
b9049df5a0 Change "useing" -> "using".
Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-09-21 15:14:53 +02:00
Oleg Nesterov
4e49627b9b workqueues: introduce __cancel_delayed_work()
cancel_delayed_work() has to use del_timer_sync() to guarantee the timer
function is not running after return.  But most users doesn't actually
need this, and del_timer_sync() has problems: it is not useable from
interrupt, and it depends on every lock which could be taken from irq.

Introduce __cancel_delayed_work() which calls del_timer() instead.

The immediate reason for this patch is
http://bugzilla.kernel.org/show_bug.cgi?id=13757
but hopefully this helper makes sense anyway.

As for 13757 bug, actually we need requeue_delayed_work(), but its
semantics are not yet clear.

Merge this patch early to resolves cross-tree interdependencies between
input and infiniband.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-05 11:30:42 -07:00
Jean Delvare
bf6aede712 workqueue: add to_delayed_work() helper function
It is a fairly common operation to have a pointer to a work and to need a
pointer to the delayed work it is contained in.  In particular, all
delayed works which want to rearm themselves will have to do that.  So it
would seem fair to offer a helper function for this operation.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Greg KH <greg@kroah.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:50 -07:00
Linus Torvalds
3386c05bdb Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  debugobjects: add and use INIT_WORK_ON_STACK
  rcu: remove duplicate CONFIG_RCU_CPU_STALL_DETECTOR
  relay: fix lock imbalance in relay_late_setup_files
  oprofile: fix uninitialized use of struct op_entry
  rcu: move Kconfig menu
  softlock: fix false panic which can occur if softlockup_thresh is reduced
  rcu: add __cpuinit to rcu_init_percpu_data()
2009-01-26 09:47:56 -08:00
Thomas Gleixner
336f6c322d debugobjects: add and use INIT_WORK_ON_STACK
Impact: Fix debugobjects warning

debugobject enabled kernels spit out a warning in hpet code due to a
workqueue which is initialized on stack.

Add INIT_WORK_ON_STACK() which calls init_timer_on_stack() and use it
in hpet.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-01-22 10:02:07 +01:00
Peter Zijlstra
6d612b0f94 locking, hpet: annotate false positive warning
Alexander Beregalov reported that this warning is caused by the HPET code:

> hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0
> hpet0: 3 comparators, 64-bit 14.318180 MHz counter
> ODEBUG: object is on stack, but not annotated
> ------------[ cut here ]------------
> WARNING: at lib/debugobjects.c:251 __debug_object_init+0x2a4/0x352()

> Bisected down to 26afe5f2fb
> (x86: HPET_MSI Initialise per-cpu HPET timers)

The commit is fine - but the on-stack workqueue entry needs annotation.

Reported-and-bisected-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-12 13:33:20 +01:00
Rusty Russell
2d3854a37e cpumask: introduce new API, without changing anything
Impact: introduce new APIs

We want to deprecate cpumasks on the stack, as we are headed for
gynormous numbers of CPUs.  Eventually, we want to head towards an
undefined 'struct cpumask' so they can never be declared on stack.

1) New cpumask functions which take pointers instead of copies.
   (cpus_* -> cpumask_*)

2) Several new helpers to reduce requirements for temporary cpumasks
   (cpumask_first_and, cpumask_next_and, cpumask_any_and)

3) Helpers for declaring cpumasks on or offstack for large NR_CPUS
   (cpumask_var_t, alloc_cpumask_var and free_cpumask_var)

4) 'struct cpumask' for explicitness and to mark new-style code.

5) Make iterator functions stop at nr_cpu_ids (a runtime constant),
   not NR_CPUS for time efficiency and for smaller dynamic allocations
   in future.

6) cpumask_copy() so we can allocate less than a full cpumask eventually
   (for alloc_cpumask_var), and so we can eliminate the 'struct cpumask'
   definition eventually.

7) work_on_cpu() helper for doing task on a CPU, rather than saving old
   cpumask for current thread and manipulating it.

8) smp_call_function_many() which is smp_call_function_mask() except
   taking a cpumask pointer.

Note that this patch simply introduces the new functions and leaves
the obsolescent ones in place.  This is to simplify the transition
patches.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-06 09:05:33 +01:00
Heiko Carstens
0d557dc97f workqueue: introduce create_rt_workqueue
create_rt_workqueue will create a real time prioritized workqueue.
This is needed for the conversion of stop_machine to a workqueue based
implementation.
This patch adds yet another parameter to __create_workqueue_key to tell
it that we want an rt workqueue.
However it looks like we rather should have something like "int type"
instead of singlethread, freezable and rt.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
2008-10-22 10:00:25 +11:00
Oleg Nesterov
db70089722 workqueues: implement flush_work()
Most of users of flush_workqueue() can be changed to use cancel_work_sync(),
but sometimes we really need to wait for the completion and cancelling is not
an option. schedule_on_each_cpu() is good example.

Add the new helper, flush_work(work), which waits for the completion of the
specific work_struct. More precisely, it "flushes" the result of of the last
queue_work() which is visible to the caller.

For example, this code

	queue_work(wq, work);
	/* WINDOW */
	queue_work(wq, work);

	flush_work(work);

doesn't necessary work "as expected". What can happen in the WINDOW above is

	- wq starts the execution of work->func()

	- the caller migrates to another CPU

now, after the 2nd queue_work() this work is active on the previous CPU, and
at the same time it is queued on another. In this case flush_work(work) may
return before the first work->func() completes.

It is trivial to add another helper

	int flush_work_sync(struct work_struct *work)
	{
		return flush_work(work) || wait_on_work(work);
	}

which works "more correctly", but it has to iterate over all CPUs and thus
it much slower than flush_work().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Max Krasnyansky <maxk@qualcomm.com>
Acked-by: Jarek Poplawski <jarkao2@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:40 -07:00
Zhang Rui
c1a220e7ac pm: introduce new interfaces schedule_work_on() and queue_work_on()
This interface allows adding a job on a specific cpu.

Although a work struct on a cpu will be scheduled to other cpu if the cpu
dies, there is a recursion if a work task tries to offline the cpu it's
running on.  we need to schedule the task to a specific cpu in this case.
http://bugzilla.kernel.org/show_bug.cgi?id=10897

[oleg@tv-sign.ru: cleanups]
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Tested-by: Rus <harbour@sfinx.od.ua>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 10:47:23 -07:00
Harvey Harrison
b3c9752868 include/linux: Remove all users of FASTCALL() macro
FASTCALL() is always expanded to empty, remove it.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-13 16:21:18 -08:00
Johannes Berg
eb13ba8738 lockdep: fix workqueue creation API lockdep interaction
Dave Young reported warnings from lockdep that the workqueue API
can sometimes try to register lockdep classes with the same key
but different names. This is not permitted in lockdep.

Unfortunately, I was unaware of that restriction when I wrote
the code to debug workqueue problems with lockdep and used the
workqueue name as the lockdep class name. This can obviously
lead to the problem if the workqueue name is dynamic.

This patch solves the problem by always using a constant name
for the workqueue's lockdep class, namely either the constant
name that was passed in or a string consisting of the variable
name.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2008-01-16 09:51:58 +01:00
Johannes Berg
4e6045f134 workqueue: debug flushing deadlocks with lockdep
In the following scenario:

code path 1:
  my_function() -> lock(L1); ...; flush_workqueue(); ...

code path 2:
  run_workqueue() -> my_work() -> ...; lock(L1); ...

you can get a deadlock when my_work() is queued or running
but my_function() has acquired L1 already.

This patch adds a pseudo-lock to each workqueue to make lockdep
warn about this scenario.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:38 -07:00
Oleg Nesterov
1f1f642e2f make cancel_xxx_work_sync() return a boolean
Change cancel_work_sync() and cancel_delayed_work_sync() to return a boolean
indicating whether the work was actually cancelled.  A zero return value means
that the work was not pending/queued.

Without that kind of change it is not possible to avoid flush_workqueue()
sometimes, see the next patch as an example.

Also, this patch unifies both functions and kills the (unlikely) busy-wait
loop.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:51 -07:00
Oleg Nesterov
f5a421a450 rename cancel_rearming_delayed_work() to cancel_delayed_work_sync()
Imho, the current naming of cancel_xxx workqueue functions is very confusing.

	cancel_delayed_work()
	cancel_rearming_delayed_work()
	cancel_rearming_delayed_workqueue()	// obsolete

	cancel_work_sync()

This looks as if the first 2 functions differ in "type" of their argument
which is not true any longer, nowadays the difference is the behaviour.

The semantics of cancel_rearming_delayed_work(dwork) was changed
significantly, it doesn't require that dwork rearms itself, and cancels dwork
synchronously.

Rename it to cancel_delayed_work_sync().  This matches cancel_delayed_work()
and cancel_work_sync().  Re-create cancel_rearming_delayed_work() as a simple
inline obsolete wrapper, like cancel_rearming_delayed_workqueue().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:51 -07:00
Oleg Nesterov
223a10a981 revert "cancel_delayed_work: use del_timer() instead of del_timer_sync()"
As pointed out by Jarek Poplawski, the patch

	[WORKQUEUE]: cancel_delayed_work: use del_timer() instead of del_timer_sync()
	commit: 071b638689

was wrong, it was merged by mistake after that.

From the changelog:

	after this patch:
		...
		delayed_work_timer_fn->__queue_work() in progress.

		The latter doesn't differ from the caller's POV,

it does make a difference if the caller calls flush_workqueue() after
cancel_delayed_work(), in that case flush_workqueue() can miss this
work_struct.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Jarek Poplawski <jarkao2@o2.pl>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-18 08:17:17 -07:00
Oleg Nesterov
e3dfd2964e make freezeable workqueues singlethread
It is a known fact that freezeable multithreaded workqueues doesn't like
CPU_DEAD. We keep them only for the incoming CPU-hotplug rework.

Sadly, we can't just kill create_freezeable_workqueue() right now, make
them singlethread.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17 05:23:05 -07:00
Oleg Nesterov
28e53bddf8 unify flush_work/flush_work_keventd and rename it to cancel_work_sync
flush_work(wq, work) doesn't need the first parameter, we can use cwq->wq
(this was possible from the very beginnig, I missed this).  So we can unify
flush_work_keventd and flush_work.

Also, rename flush_work() to cancel_work_sync() and fix all callers.
Perhaps this is not the best name, but "flush_work" is really bad.

(akpm: this is why the earlier patches bypassed maintainers)

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Auke Kok <auke-jan.h.kok@intel.com>,
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:53 -07:00
Oleg Nesterov
23b2e5991a workqueue: kill NOAUTOREL works
We don't have any users, and it is not so trivial to use NOAUTOREL works
correctly.  It is better to simplify API.

Delete NOAUTOREL support and rename work_release to work_clear_pending to
avoid a confusion.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:52 -07:00
Oleg Nesterov
1634c48f8b make cancel_rearming_delayed_work() work on any workqueue, not just keventd_wq
cancel_rearming_delayed_workqueue(wq, dwork) doesn't need the first
parameter.  We don't hang on un-queued dwork any longer, and work->data
doesn't change its type.  This means we can always figure out "wq" from
dwork when it is needed.

Remove this parameter, and rename the function to
cancel_rearming_delayed_work().  Re-create an inline "obsolete"
cancel_rearming_delayed_workqueue(wq) which just calls
cancel_rearming_delayed_work().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:52 -07:00
Oleg Nesterov
7097a87afe workqueue: kill run_scheduled_work()
Because it has no callers.

Actually, I think the whole idea of run_scheduled_work() was not right, not
good to mix "unqueue this work and execute its ->func()" in one function.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:52 -07:00
Oleg Nesterov
b89deed32c implement flush_work()
A basic problem with flush_scheduled_work() is that it blocks behind _all_
presently-queued works, rather than just the work whcih the caller wants to
flush.  If the caller holds some lock, and if one of the queued work happens
to want that lock as well then accidental deadlocks can occur.

One example of this is the phy layer: it wants to flush work while holding
rtnl_lock().  But if a linkwatch event happens to be queued, the phy code will
deadlock because the linkwatch callback function takes rtnl_lock.

So we implement a new function which will flush a *single* work - just the one
which the caller wants to free up.  Thus we avoid the accidental deadlocks
which can arise from unrelated subsystems' callbacks taking shared locks.

flush_work() non-blockingly dequeues the work_struct which we want to kill,
then it waits for its handler to complete on all CPUs.

Add ->current_work to the "struct cpu_workqueue_struct", it points to
currently running "struct work_struct". When flush_work(work) detects
->current_work == work, it inserts a barrier at the _head_ of ->worklist
(and thus right _after_ that work) and waits for completition. This means
that the next work fired on that CPU will be this barrier, or another
barrier queued by concurrent flush_work(), so the caller of flush_work()
will be woken before any "regular" work has a chance to run.

When wait_on_work() unlocks workqueue_mutex (or whatever we choose to protect
against CPU hotplug), CPU may go away. But in that case take_over_work() will
move a barrier we queued to another CPU, it will be fired sometime, and
wait_on_work() will be woken.

Actually, we are doing cleanup_workqueue_thread()->kthread_stop() before
take_over_work(), so cwq->thread should complete its ->worklist (and thus
the barrier), because currently we don't check kthread_should_stop() in
run_workqueue(). But even if we did, everything should be ok.

[akpm@osdl.org: cleanup]
[akpm@osdl.org: add flush_work_keventd() wrapper]
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:50 -07:00
Venki Pallipadi
28287033e1 Add a new deferrable delayed work init
Add a new deferrable delayed work init.  This can be used to schedule work
that are 'unimportant' when CPU is idle and can be called later, when CPU
eventually comes out of idle.

Use this init in cpufreq ondemand governor.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:05 -07:00
Oleg Nesterov
071b638689 [WORKQUEUE]: cancel_delayed_work: use del_timer() instead of del_timer_sync()
del_timer_sync() buys nothing for cancel_delayed_work(), but it is less
efficient since it locks the timer unconditionally, and may wait for the
completion of the delayed_work_timer_fn().

cancel_delayed_work() == 0 means:

	before this patch:
		work->func may still be running or queued

	after this patch:
		work->func may still be running or queued, or
		delayed_work_timer_fn->__queue_work() in progress.

		The latter doesn't differ from the caller's POV,
		delayed_work_timer_fn() is called with _PENDING
		bit set.

cancel_delayed_work() == 1 with this patch adds a new possibility:

	delayed_work->work was cancelled, but delayed_work_timer_fn
	is still running (this is only possible for the re-arming
	works on single-threaded workqueue).

	In this case the timer was re-started by work->func(), nobody
	else can do this. This in turn means that delayed_work_timer_fn
	has already passed __queue_work() (and wont't touch delayed_work)
	because nobody else can queue delayed_work->work.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-26 15:45:32 -07:00
Linus Torvalds
a08727bae7 Make workqueue bit operations work on "atomic_long_t"
On architectures where the atomicity of the bit operations is handled by
external means (ie a separate spinlock to protect concurrent accesses),
just doing a direct assignment on the workqueue data field (as done by
commit 4594bf159f) can cause the
assignment to be lost due to lack of serialization with the bitops on
the same word.

So we need to serialize the assignment with the locks on those
architectures (notably older ARM chips, PA-RISC and sparc32).

So rather than using an "unsigned long", let's use "atomic_long_t",
which already has a safe assignment operation (atomic_long_set()) on
such architectures.

This requires that the atomic operations use the same atomicity locks as
the bit operations do, but that is largely the case anyway.  Sparc32
will probably need fixing.

Architectures (including modern ARM with LL/SC) that implement sane
atomic operations for SMP won't see any of this matter.

Cc: Russell King <rmk+lkml@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: David Miller <davem@davemloft.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Linux Arch Maintainers <linux-arch@vger.kernel.org>
Cc: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-16 09:53:50 -08:00
Linus Torvalds
0221872a3b Fix "delayed_work_pending()" macro expansion
Nobody uses it, but it was still wrong.  Using the macro argument name
'work' meant that when we used 'work' as a member name, that would also
get replaced by the macro argument.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-15 14:13:51 -08:00
Linus Torvalds
68380b5813 Add "run_scheduled_work()" workqueue function
This allows workqueue users to run just their own pending work, rather
than wait for the whole workqueue to finish running.  This solves the
deadlock with networking libphy that was due to other workqueue entries
possibly needing a lock that was held by the routine that wanted to
flush its own work.

It's not wonderful: if you absolutely need to synchronize with the work
function having been executed, any user strictly speaking should have
its own completion tracking logic, since when we run things explicitly
by hand, the generic workqueue layer can no longer help us synchronize.

Also, this is strictly only usable for work that has been scheduled
without any delayed timers.  You can not mix the new interface with
schedule_delayed_work().

But it's better than what we had currently.

Acked-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 09:28:19 -08:00
Rafael J. Wysocki
341a595850 [PATCH] Support for freezeable workqueues
Make it possible to create a workqueue the worker thread of which will be
frozen during suspend, along with other kernel threads.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@suspend2.net>
Cc: David Chinner <dgc@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:29 -08:00
David Howells
65f27f3844 WorkStruct: Pass the work_struct pointer instead of context data
Pass the work_struct pointer to the work function rather than context data.
The work function can use container_of() to work out the data.

For the cases where the container of the work_struct may go away the moment the
pending bit is cleared, it is made possible to defer the release of the
structure by deferring the clearing of the pending bit.

To make this work, an extra flag is introduced into the management side of the
work_struct.  This governs auto-release of the structure upon execution.

Ordinarily, the work queue executor would release the work_struct for further
scheduling or deallocation by clearing the pending bit prior to jumping to the
work function.  This means that, unless the driver makes some guarantee itself
that the work_struct won't go away, the work function may not access anything
else in the work_struct or its container lest they be deallocated..  This is a
problem if the auxiliary data is taken away (as done by the last patch).

However, if the pending bit is *not* cleared before jumping to the work
function, then the work function *may* access the work_struct and its container
with no problems.  But then the work function must itself release the
work_struct by calling work_release().

In most cases, automatic release is fine, so this is the default.  Special
initiators exist for the non-auto-release case (ending in _NAR).


Signed-Off-By: David Howells <dhowells@redhat.com>
2006-11-22 14:55:48 +00:00
David Howells
365970a1ea WorkStruct: Merge the pending bit into the wq_data pointer
Reclaim a word from the size of the work_struct by folding the pending bit and
the wq_data pointer together.  This shouldn't cause misalignment problems as
all pointers should be at least 4-byte aligned.

Signed-Off-By: David Howells <dhowells@redhat.com>
2006-11-22 14:54:49 +00:00
David Howells
6bb49e5965 WorkStruct: Typedef the work function prototype
Define a type for the work function prototype.  It's not only kept in the
work_struct struct, it's also passed as an argument to several functions.

This makes it easier to change it.

Signed-Off-By: David Howells <dhowells@redhat.com>
2006-11-22 14:54:45 +00:00
David Howells
52bad64d95 WorkStruct: Separate delayable and non-delayable events.
Separate delayable work items from non-delayable work items be splitting them
into a separate structure (delayed_work), which incorporates a work_struct and
the timer_list removed from work_struct.

The work_struct struct is huge, and this limits it's usefulness.  On a 64-bit
architecture it's nearly 100 bytes in size.  This reduces that by half for the
non-delayable type of event.

Signed-Off-By: David Howells <dhowells@redhat.com>
2006-11-22 14:54:01 +00:00
Venkatesh Pallipadi
7a6bc1cdd5 [CPUFREQ] Add queue_delayed_work_on() interface for workqueues.
Add queue_delayed_work_on() interface for workqueues.

Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2006-06-30 01:33:31 -04:00
James Bottomley
1fa44ecad2 [SCSI] add execute_in_process_context() API
We have several points in the SCSI stack (primarily for our device
functions) where we need to guarantee process context, but (given the
place where the last reference was released) we cannot guarantee this.

This API gets around the issue by executing the function directly if
the caller has process context, but scheduling a workqueue to execute
in process context if the caller doesn't have it.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2006-02-27 23:34:40 -06:00
Christoph Lameter
15316ba81a [PATCH] add schedule_on_each_cpu()
swap migration's isolate_lru_page() currently uses an IPI to notify other
processors that the lru caches need to be drained if the page cannot be
found on the LRU.  The IPI interrupt may interrupt a processor that is just
processing lru requests and cause a race condition.

This patch introduces a new function run_on_each_cpu() that uses the
keventd() to run the LRU draining on each processor.  Processors disable
preemption when dealing the LRU caches (these are per processor) and thus
executing LRU draining from another process is safe.

Thanks to Lee Schermerhorn <lee.schermerhorn@hp.com> for finding this race
condition.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:12:40 -08:00
James Bottomley
81ddef77bb [PATCH] re-export cancel_rearming_delayed_workqueue
This was unexported by Arjan because we have no current users.

However, during a conversion from tasklets to workqueues of the parisc led
functions, we ran across a case where this was needed.  In particular, the
open coded equivalent of cancel_rearming_delayed_workqueue was implemented
incorrectly, which is, I think, all the evidence necessary that this is a
useful API.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16 15:23:59 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00