SCHED: add some "wait..on_bit...timeout()" interfaces.

In commit c1221321b7
   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>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
NeilBrown 2014-09-25 13:55:19 +10:00 коммит произвёл Trond Myklebust
Родитель e87b4c7a7a
Коммит cbbce82209
4 изменённых файлов: 55 добавлений и 1 удалений

Просмотреть файл

@ -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)
{

Просмотреть файл

@ -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

Просмотреть файл

@ -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_GPL(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_GPL(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_GPL(bit_wait_io_timeout);

Просмотреть файл

@ -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_GPL(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