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sched: affine sync wakeups

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make sync wakeups affine for cache-cold tasks: if a cache-cold task
is woken up by a sync wakeup then use the opportunity to migrate it
straight away. (the two tasks are 'related' because they communicate)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2007-10-15 17:00:19 +02:00
parent d172fcd3ae
commit 71e20f1873
3 changed files with 12 additions and 6 deletions
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6
fs/pipe.c
View file

@ -382,7 +382,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
/* Signal writers asynchronously that there is more room. */
if (do_wakeup) {
wake_up_interruptible(&pipe->wait);
wake_up_interruptible_sync(&pipe->wait);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
if (ret > 0)
@ -555,7 +555,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
out:
mutex_unlock(&inode->i_mutex);
if (do_wakeup) {
wake_up_interruptible(&pipe->wait);
wake_up_interruptible_sync(&pipe->wait);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
}
if (ret > 0)
@ -649,7 +649,7 @@ pipe_release(struct inode *inode, int decr, int decw)
if (!pipe->readers && !pipe->writers) {
free_pipe_info(inode);
} else {
wake_up_interruptible(&pipe->wait);
wake_up_interruptible_sync(&pipe->wait);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}

8
kernel/sched.c
View file

@ -1521,6 +1521,12 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
unsigned long tl = this_load;
unsigned long tl_per_task;
/*
* Attract cache-cold tasks on sync wakeups:
*/
if (sync && !task_hot(p, rq->clock, this_sd))
goto out_set_cpu;
schedstat_inc(p, se.nr_wakeups_affine_attempts);
tl_per_task = cpu_avg_load_per_task(this_cpu);
@ -1598,7 +1604,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
* the waker guarantees that the freshly woken up task is going
* to be considered on this CPU.)
*/
if (!sync || cpu != this_cpu)
if (!sync || rq->curr == rq->idle)
check_preempt_curr(rq, p);
success = 1;

4
net/unix/af_unix.c
View file

@ -334,7 +334,7 @@ static void unix_write_space(struct sock *sk)
read_lock(&sk->sk_callback_lock);
if (unix_writable(sk)) {
if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
wake_up_interruptible(sk->sk_sleep);
wake_up_interruptible_sync(sk->sk_sleep);
sk_wake_async(sk, 2, POLL_OUT);
}
read_unlock(&sk->sk_callback_lock);
@ -1639,7 +1639,7 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
if (!skb)
goto out_unlock;
wake_up_interruptible(&u->peer_wait);
wake_up_interruptible_sync(&u->peer_wait);
if (msg->msg_name)
unix_copy_addr(msg, skb->sk);