[FFmpeg-devel] [PATCH] lavfi/pthread: Avoid crashes/odd behavior caused by spurious wakeups
Michael Niedermayer
michaelni at gmx.at
Sat Oct 19 15:25:50 CEST 2013
On Fri, Oct 18, 2013 at 03:33:22PM +0100, Derek Buitenhuis wrote:
> This is similar to e3329474a366de066b25e86f35f5abf9c5a4b7b2.
>
> Signed-off-by: Derek Buitenhuis <derek.buitenhuis at gmail.com>
> ---
> libavfilter/pthread.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/libavfilter/pthread.c b/libavfilter/pthread.c
> index 8ae2c3f..91fb4c6 100644
> --- a/libavfilter/pthread.c
> +++ b/libavfilter/pthread.c
> @@ -58,6 +58,7 @@ typedef struct ThreadContext {
> pthread_cond_t current_job_cond;
> pthread_mutex_t current_job_lock;
> int current_job;
> + unsigned int current_execute;
> int done;
> } ThreadContext;
>
> @@ -66,6 +67,7 @@ static void* attribute_align_arg worker(void *v)
> ThreadContext *c = v;
> int our_job = c->nb_jobs;
> int nb_threads = c->nb_threads;
> + int last_execute = 0;
> int self_id;
>
> pthread_mutex_lock(&c->current_job_lock);
> @@ -75,8 +77,9 @@ static void* attribute_align_arg worker(void *v)
> if (c->current_job == nb_threads + c->nb_jobs)
> pthread_cond_signal(&c->last_job_cond);
>
> - if (!c->done)
> + while (last_execute == c->current_execute && !c->done)
> pthread_cond_wait(&c->current_job_cond, &c->current_job_lock);
> + last_execute = c->current_execute;
> our_job = self_id;
>
> if (c->done) {
> @@ -113,7 +116,8 @@ static void slice_thread_uninit(ThreadContext *c)
>
> static void slice_thread_park_workers(ThreadContext *c)
> {
> - pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
> + while (c->current_job != thread_count + c->job_count)
> + pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
> pthread_mutex_unlock(&c->current_job_lock);
> }
thread_count looks undeclared here
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
I have never wished to cater to the crowd; for what I know they do not
approve, and what they approve I do not know. -- Epicurus
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