On 8/27/21 8:32 AM, Juergen Gross wrote:
> +static bool balloon_thread_cond(enum bp_state state, long credit)
> +{
> + if (state != BP_EAGAIN)
> + credit = 0;
> +
> + return current_credit() != credit || kthread_should_stop();
> +}
> +
> +/*
> + * As this is a kthread it is guaranteed to run as a single instance only.
> * We may of course race updates of the target counts (which are protected
> * by the balloon lock), or with changes to the Xen hard limit, but we will
> * recover from these in time.
> */
> -static void balloon_process(struct work_struct *work)
> +static int balloon_thread(void *unused)
> {
> enum bp_state state = BP_DONE;
> long credit;
> + unsigned long timeout;
> +
> + set_freezable();
> + for (;;) {
> + if (state == BP_EAGAIN)
> + timeout = balloon_stats.schedule_delay * HZ;
> + else
> + timeout = 3600 * HZ;
> + credit = current_credit();
>
> + wait_event_interruptible_timeout(balloon_thread_wq,
> + balloon_thread_cond(state, credit), timeout);
Given that wait_event_interruptible_timeout() is a bunch of nested macros do we
need to worry here about overly aggressive compiler optimizing out 'credit =
current_credit()'?
-boris
