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sched/wait: Introduce init_wait_entry()

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The partial initialization of wait_queue_t in prepare_to_wait_event() looks
ugly. This was done to shrink .text, but we can simply add the new helper
which does the full initialization and shrink the compiled code a bit more.

And. This way prepare_to_wait_event() can have more users. In particular we
are ready to remove the signal_pending_state() checks from wait_bit_action_f
helpers and change __wait_on_bit_lock() to use prepare_to_wait_event().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160906140055.GA6167@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Oleg Nesterov 2016-09-06 16:00:55 +02:00 committed by Ingo Molnar
parent eaf9ef5224
commit 0176beaffb
2 changed files with 12 additions and 9 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

9
include/linux/wait.h
View file

@ -248,6 +248,8 @@ wait_queue_head_t *bit_waitqueue(void *, int);
(!__builtin_constant_p(state) || \
state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \
extern void init_wait_entry(wait_queue_t *__wait, int flags);
/*
* The below macro ___wait_event() has an explicit shadow of the __ret
* variable when used from the wait_event_*() macros.
@ -266,12 +268,7 @@ wait_queue_head_t *bit_waitqueue(void *, int);
wait_queue_t __wait; \
long __ret = ret; /* explicit shadow */ \
\
INIT_LIST_HEAD(&__wait.task_list); \
if (exclusive) \
__wait.flags = WQ_FLAG_EXCLUSIVE; \
else \
__wait.flags = 0; \
\
init_wait_entry(&__wait, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \
for (;;) { \
long __int = prepare_to_wait_event(&wq, &__wait, state);\
\

12
kernel/sched/wait.c
View file

@ -196,14 +196,20 @@ prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state)
}
EXPORT_SYMBOL(prepare_to_wait_exclusive);
void init_wait_entry(wait_queue_t *wait, int flags)
{
wait->flags = flags;
wait->private = current;
wait->func = autoremove_wake_function;
INIT_LIST_HEAD(&wait->task_list);
}
EXPORT_SYMBOL(init_wait_entry);
long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state)
{
unsigned long flags;
long ret = 0;
wait->private = current;
wait->func = autoremove_wake_function;
spin_lock_irqsave(&q->lock, flags);
if (unlikely(signal_pending_state(state, current))) {
/*