On 2018-01-19 21:58, John Snow wrote: > Instead of only sleeping for 0ms when we've hit a timeout, optionally > take a longer more explicit delay_ns that always forces the sleep. > > Signed-off-by: John Snow <js...@redhat.com> > --- > block/mirror.c | 4 ++-- > blockjob.c | 9 ++++----- > include/block/blockjob_int.h | 10 +++++++--- > 3 files changed, 13 insertions(+), 10 deletions(-)
[...]
> diff --git a/blockjob.c b/blockjob.c
> index 6f2e709b51..51c0eb5d9e 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -906,12 +906,11 @@ void block_job_yield(BlockJob *job)
> block_job_pause_point(job);
> }
>
> -void block_job_relax(BlockJob *job)
> +void block_job_relax(BlockJob *job, int64_t delay_ns)
> {
> - int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
> -
> - if (now - job->last_enter_ns > SLICE_TIME) {
> - block_job_sleep_ns(job, 0);
> + if (delay_ns || (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - \
> + job->last_enter_ns > SLICE_TIME)) {
> + block_job_sleep_ns(job, delay_ns);
I can't say I like the readability of that any better...
(And I'd argue that if delay_ns > 0, the one superfluous call to
qemu_clock_get_ns() isn't going to harm performance.)
> } else {
> block_job_pause_point(job);
> }
> diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
> index 553784d86f..5f1520fab7 100644
> --- a/include/block/blockjob_int.h
> +++ b/include/block/blockjob_int.h
> @@ -160,11 +160,15 @@ void block_job_yield(BlockJob *job);
> /**
> * block_job_relax:
> * @job: The job that calls the function.
> + * @delay_ns: The amount of time to sleep for
> *
> - * Yield if it has been SLICE_TIME nanoseconds since the last yield.
> - * Otherwise, check if we need to pause, and yield if so.
> + * Sleep for delay_ns nanoseconds.
> + *
> + * If delay_ns is 0, yield if it has been SLICE_TIME
> + * nanoseconds since the last yield. Otherwise, check
> + * if we need to yield for a pause event.
That "Otherwise" now sounds as if it refers to the "If delay_ns is 0".
Code change is OK, but this comment needs some fixing.
Max
> */
> -void block_job_relax(BlockJob *job);
> +void block_job_relax(BlockJob *job, int64_t delay_ns);
>
> /**
> * block_job_pause_all:
>
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