diff mbox

[1/5] SCHED: add some "wait..on_bit...timeout()" interfaces.

Message ID 20140924012832.4838.59410.stgit@notabene.brown (mailing list archive)
State New, archived
Headers show

Commit Message

NeilBrown Sept. 24, 2014, 1:28 a.m. UTC 
In commit c1221321b7c25b53204447cff9949a6d5a7ddddc
   sched: Allow wait_on_bit_action() functions to support a timeout

I suggested that a "wait_on_bit_timeout()" interface would not meet my
need.  This isn't true - I was just over-engineering.

Including a 'private' field in wait_bit_key instead of a focused
"timeout" field was just premature generalization.  If some other
use is ever found, it can be generalized or added later.

So this patch renames "private" to "timeout" with a meaning "stop
waiting when "jiffies" reaches or passes "timeout",
and adds two of the many possible wait..bit..timeout() interfaces:

wait_on_page_bit_killable_timeout(), which is the one I want to use,
and out_of_line_wait_on_bit_timeout() which is a reasonably general
example.  Others can be added as needed.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NeilBrown <neilb@suse.de>
---
 include/linux/pagemap.h |    2 ++
 include/linux/wait.h    |    5 ++++-
 kernel/sched/wait.c     |   36 ++++++++++++++++++++++++++++++++++++
 mm/filemap.c            |   13 +++++++++++++
 4 files changed, 55 insertions(+), 1 deletion(-)



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Comments

Ingo Molnar Sept. 24, 2014, 7:04 a.m. UTC | #1 
* NeilBrown <neilb@suse.de> wrote:

> @@ -859,6 +860,8 @@ int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
>  
>  extern int bit_wait(struct wait_bit_key *);
>  extern int bit_wait_io(struct wait_bit_key *);
> +extern int bit_wait_timeout(struct wait_bit_key *);
> +extern int bit_wait_io_timeout(struct wait_bit_key *);
>  
>  /**
>   * wait_on_bit - wait for a bit to be cleared
> diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
> index 15cab1a4f84e..380678b3cba4 100644
> --- a/kernel/sched/wait.c
> +++ b/kernel/sched/wait.c
> @@ -343,6 +343,18 @@ int __sched out_of_line_wait_on_bit(void *word, int bit,
>  }
>  EXPORT_SYMBOL(out_of_line_wait_on_bit);
>  
> +int __sched out_of_line_wait_on_bit_timeout(
> +	void *word, int bit, wait_bit_action_f *action,
> +	unsigned mode, unsigned long timeout)
> +{
> +	wait_queue_head_t *wq = bit_waitqueue(word, bit);
> +	DEFINE_WAIT_BIT(wait, word, bit);
> +
> +	wait.key.timeout = jiffies + timeout;
> +	return __wait_on_bit(wq, &wait, action, mode);
> +}
> +EXPORT_SYMBOL(out_of_line_wait_on_bit_timeout);
> +
>  int __sched
>  __wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q,
>  			wait_bit_action_f *action, unsigned mode)
> @@ -520,3 +532,27 @@ __sched int bit_wait_io(struct wait_bit_key *word)
>  	return 0;
>  }
>  EXPORT_SYMBOL(bit_wait_io);
> +
> +__sched int bit_wait_timeout(struct wait_bit_key *word)
> +{
> +	unsigned long now = ACCESS_ONCE(jiffies);
> +	if (signal_pending_state(current->state, current))
> +		return 1;
> +	if (time_after_eq(now, word->timeout))
> +		return -EAGAIN;
> +	schedule_timeout(word->timeout - now);
> +	return 0;
> +}
> +EXPORT_SYMBOL(bit_wait_timeout);
> +
> +__sched int bit_wait_io_timeout(struct wait_bit_key *word)
> +{
> +	unsigned long now = ACCESS_ONCE(jiffies);
> +	if (signal_pending_state(current->state, current))
> +		return 1;
> +	if (time_after_eq(now, word->timeout))
> +		return -EAGAIN;
> +	io_schedule_timeout(word->timeout - now);
> +	return 0;
> +}
> +EXPORT_SYMBOL(bit_wait_io_timeout);

New scheduler APIs should be exported via EXPORT_SYMBOL_GPL().

Thanks,

	Ingo
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NeilBrown Sept. 25, 2014, 3:23 a.m. UTC | #2 
On Wed, 24 Sep 2014 09:04:18 +0200 Ingo Molnar <mingo@kernel.org> wrote:

> 
> * NeilBrown <neilb@suse.de> wrote:
> 
> > @@ -859,6 +860,8 @@ int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
> >  
> >  extern int bit_wait(struct wait_bit_key *);
> >  extern int bit_wait_io(struct wait_bit_key *);
> > +extern int bit_wait_timeout(struct wait_bit_key *);
> > +extern int bit_wait_io_timeout(struct wait_bit_key *);
> >  
> >  /**
> >   * wait_on_bit - wait for a bit to be cleared
> > diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
> > index 15cab1a4f84e..380678b3cba4 100644
> > --- a/kernel/sched/wait.c
> > +++ b/kernel/sched/wait.c
> > @@ -343,6 +343,18 @@ int __sched out_of_line_wait_on_bit(void *word, int bit,
> >  }
> >  EXPORT_SYMBOL(out_of_line_wait_on_bit);
> >  
> > +int __sched out_of_line_wait_on_bit_timeout(
> > +	void *word, int bit, wait_bit_action_f *action,
> > +	unsigned mode, unsigned long timeout)
> > +{
> > +	wait_queue_head_t *wq = bit_waitqueue(word, bit);
> > +	DEFINE_WAIT_BIT(wait, word, bit);
> > +
> > +	wait.key.timeout = jiffies + timeout;
> > +	return __wait_on_bit(wq, &wait, action, mode);
> > +}
> > +EXPORT_SYMBOL(out_of_line_wait_on_bit_timeout);
> > +
> >  int __sched
> >  __wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q,
> >  			wait_bit_action_f *action, unsigned mode)
> > @@ -520,3 +532,27 @@ __sched int bit_wait_io(struct wait_bit_key *word)
> >  	return 0;
> >  }
> >  EXPORT_SYMBOL(bit_wait_io);
> > +
> > +__sched int bit_wait_timeout(struct wait_bit_key *word)
> > +{
> > +	unsigned long now = ACCESS_ONCE(jiffies);
> > +	if (signal_pending_state(current->state, current))
> > +		return 1;
> > +	if (time_after_eq(now, word->timeout))
> > +		return -EAGAIN;
> > +	schedule_timeout(word->timeout - now);
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(bit_wait_timeout);
> > +
> > +__sched int bit_wait_io_timeout(struct wait_bit_key *word)
> > +{
> > +	unsigned long now = ACCESS_ONCE(jiffies);
> > +	if (signal_pending_state(current->state, current))
> > +		return 1;
> > +	if (time_after_eq(now, word->timeout))
> > +		return -EAGAIN;
> > +	io_schedule_timeout(word->timeout - now);
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(bit_wait_io_timeout);
> 
> New scheduler APIs should be exported via EXPORT_SYMBOL_GPL().
> 

Fine with me.

 Trond, can you just edit that into the patch you have, or do you want me to
 re-send?
 Also maybe added Jeff's 
    Acked-by: Jeff Layton <jlayton@primarydata.com>
 to the NFS bits.

Thanks,
NeilBrown
Trond Myklebust Sept. 25, 2014, 3:28 a.m. UTC | #3 
On Wed, Sep 24, 2014 at 11:23 PM, NeilBrown <neilb@suse.de> wrote:
> On Wed, 24 Sep 2014 09:04:18 +0200 Ingo Molnar <mingo@kernel.org> wrote:
>
>>
>> * NeilBrown <neilb@suse.de> wrote:
>>
>> > @@ -859,6 +860,8 @@ int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
>> >
>> >  extern int bit_wait(struct wait_bit_key *);
>> >  extern int bit_wait_io(struct wait_bit_key *);
>> > +extern int bit_wait_timeout(struct wait_bit_key *);
>> > +extern int bit_wait_io_timeout(struct wait_bit_key *);
>> >
>> >  /**
>> >   * wait_on_bit - wait for a bit to be cleared
>> > diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
>> > index 15cab1a4f84e..380678b3cba4 100644
>> > --- a/kernel/sched/wait.c
>> > +++ b/kernel/sched/wait.c
>> > @@ -343,6 +343,18 @@ int __sched out_of_line_wait_on_bit(void *word, int bit,
>> >  }
>> >  EXPORT_SYMBOL(out_of_line_wait_on_bit);
>> >
>> > +int __sched out_of_line_wait_on_bit_timeout(
>> > +   void *word, int bit, wait_bit_action_f *action,
>> > +   unsigned mode, unsigned long timeout)
>> > +{
>> > +   wait_queue_head_t *wq = bit_waitqueue(word, bit);
>> > +   DEFINE_WAIT_BIT(wait, word, bit);
>> > +
>> > +   wait.key.timeout = jiffies + timeout;
>> > +   return __wait_on_bit(wq, &wait, action, mode);
>> > +}
>> > +EXPORT_SYMBOL(out_of_line_wait_on_bit_timeout);
>> > +
>> >  int __sched
>> >  __wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q,
>> >                     wait_bit_action_f *action, unsigned mode)
>> > @@ -520,3 +532,27 @@ __sched int bit_wait_io(struct wait_bit_key *word)
>> >     return 0;
>> >  }
>> >  EXPORT_SYMBOL(bit_wait_io);
>> > +
>> > +__sched int bit_wait_timeout(struct wait_bit_key *word)
>> > +{
>> > +   unsigned long now = ACCESS_ONCE(jiffies);
>> > +   if (signal_pending_state(current->state, current))
>> > +           return 1;
>> > +   if (time_after_eq(now, word->timeout))
>> > +           return -EAGAIN;
>> > +   schedule_timeout(word->timeout - now);
>> > +   return 0;
>> > +}
>> > +EXPORT_SYMBOL(bit_wait_timeout);
>> > +
>> > +__sched int bit_wait_io_timeout(struct wait_bit_key *word)
>> > +{
>> > +   unsigned long now = ACCESS_ONCE(jiffies);
>> > +   if (signal_pending_state(current->state, current))
>> > +           return 1;
>> > +   if (time_after_eq(now, word->timeout))
>> > +           return -EAGAIN;
>> > +   io_schedule_timeout(word->timeout - now);
>> > +   return 0;
>> > +}
>> > +EXPORT_SYMBOL(bit_wait_io_timeout);
>>
>> New scheduler APIs should be exported via EXPORT_SYMBOL_GPL().
>>
>
> Fine with me.
>
>  Trond, can you just edit that into the patch you have, or do you want me to
>  re-send?
>  Also maybe added Jeff's
>     Acked-by: Jeff Layton <jlayton@primarydata.com>
>  to the NFS bits.
>

Can you please resend just this patch so that the final version goes
out to linux-mm, linux-kernel etc?
I can edit in the Acked-by Jeff to the NFS bits as I apply.
diff mbox

Patch

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 3df8c7db7a4e..87f9e4230d3a 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -502,6 +502,8 @@  static inline int lock_page_or_retry(struct page *page, struct mm_struct *mm,
 extern void wait_on_page_bit(struct page *page, int bit_nr);
 
 extern int wait_on_page_bit_killable(struct page *page, int bit_nr);
+extern int wait_on_page_bit_killable_timeout(struct page *page,
+					     int bit_nr, unsigned long timeout);
 
 static inline int wait_on_page_locked_killable(struct page *page)
 {
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 6fb1ba5f9b2f..80115bf88671 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -25,7 +25,7 @@  struct wait_bit_key {
 	void			*flags;
 	int			bit_nr;
 #define WAIT_ATOMIC_T_BIT_NR	-1
-	unsigned long		private;
+	unsigned long		timeout;
 };
 
 struct wait_bit_queue {
@@ -154,6 +154,7 @@  int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_ac
 void wake_up_bit(void *, int);
 void wake_up_atomic_t(atomic_t *);
 int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
+int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long);
 int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
 wait_queue_head_t *bit_waitqueue(void *, int);
@@ -859,6 +860,8 @@  int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 
 extern int bit_wait(struct wait_bit_key *);
 extern int bit_wait_io(struct wait_bit_key *);
+extern int bit_wait_timeout(struct wait_bit_key *);
+extern int bit_wait_io_timeout(struct wait_bit_key *);
 
 /**
  * wait_on_bit - wait for a bit to be cleared
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
index 15cab1a4f84e..380678b3cba4 100644
--- a/kernel/sched/wait.c
+++ b/kernel/sched/wait.c
@@ -343,6 +343,18 @@  int __sched out_of_line_wait_on_bit(void *word, int bit,
 }
 EXPORT_SYMBOL(out_of_line_wait_on_bit);
 
+int __sched out_of_line_wait_on_bit_timeout(
+	void *word, int bit, wait_bit_action_f *action,
+	unsigned mode, unsigned long timeout)
+{
+	wait_queue_head_t *wq = bit_waitqueue(word, bit);
+	DEFINE_WAIT_BIT(wait, word, bit);
+
+	wait.key.timeout = jiffies + timeout;
+	return __wait_on_bit(wq, &wait, action, mode);
+}
+EXPORT_SYMBOL(out_of_line_wait_on_bit_timeout);
+
 int __sched
 __wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q,
 			wait_bit_action_f *action, unsigned mode)
@@ -520,3 +532,27 @@  __sched int bit_wait_io(struct wait_bit_key *word)
 	return 0;
 }
 EXPORT_SYMBOL(bit_wait_io);
+
+__sched int bit_wait_timeout(struct wait_bit_key *word)
+{
+	unsigned long now = ACCESS_ONCE(jiffies);
+	if (signal_pending_state(current->state, current))
+		return 1;
+	if (time_after_eq(now, word->timeout))
+		return -EAGAIN;
+	schedule_timeout(word->timeout - now);
+	return 0;
+}
+EXPORT_SYMBOL(bit_wait_timeout);
+
+__sched int bit_wait_io_timeout(struct wait_bit_key *word)
+{
+	unsigned long now = ACCESS_ONCE(jiffies);
+	if (signal_pending_state(current->state, current))
+		return 1;
+	if (time_after_eq(now, word->timeout))
+		return -EAGAIN;
+	io_schedule_timeout(word->timeout - now);
+	return 0;
+}
+EXPORT_SYMBOL(bit_wait_io_timeout);
diff --git a/mm/filemap.c b/mm/filemap.c
index 90effcdf948d..4a19c084bdb1 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -703,6 +703,19 @@  int wait_on_page_bit_killable(struct page *page, int bit_nr)
 			     bit_wait_io, TASK_KILLABLE);
 }
 
+int wait_on_page_bit_killable_timeout(struct page *page,
+				       int bit_nr, unsigned long timeout)
+{
+	DEFINE_WAIT_BIT(wait, &page->flags, bit_nr);
+
+	wait.key.timeout = jiffies + timeout;
+	if (!test_bit(bit_nr, &page->flags))
+		return 0;
+	return __wait_on_bit(page_waitqueue(page), &wait,
+			     bit_wait_io_timeout, TASK_KILLABLE);
+}
+EXPORT_SYMBOL(wait_on_page_bit_killable_timeout);
+
 /**
  * add_page_wait_queue - Add an arbitrary waiter to a page's wait queue
  * @page: Page defining the wait queue of interest