sched/wait: Introduce init_wait_entry() (0176beaf) · Commits · 戴 / test

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>

include/linux/wait.h

+3 −6

Original line number	Diff line number	Diff line
		@@ -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);\
		\

kernel/sched/wait.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -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))) {
		/*

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