[pulseaudio-discuss] [PATCH v8] pipe-source: implement autosuspend option

Georg Chini georg at chini.tk
Tue Feb 20 16:02:58 UTC 2018


On 20.02.2018 16:38, Raman Shyshniou wrote:
> Currently the pipe-source will remain running even if no
> writer is connected and therefore no data is produced.
> This patch adds the autosuspend=<bool> option to prevent this.
> Source will stay suspended if no writer is connected.
> This option is enabled by default.
> ---
>   src/modules/module-pipe-source.c | 279 +++++++++++++++++++++++++++++----------
>   1 file changed, 212 insertions(+), 67 deletions(-)
>
> diff --git a/src/modules/module-pipe-source.c b/src/modules/module-pipe-source.c
> index f8284c1..359cdbf 100644
> --- a/src/modules/module-pipe-source.c
> +++ b/src/modules/module-pipe-source.c
> @@ -33,6 +33,7 @@
>   #include <sys/filio.h>
>   #endif
>   
> +#include <pulse/rtclock.h>
>   #include <pulse/xmalloc.h>
>   
>   #include <pulsecore/core-error.h>
> @@ -57,11 +58,24 @@ PA_MODULE_USAGE(
>           "format=<sample format> "
>           "rate=<sample rate> "
>           "channels=<number of channels> "
> -        "channel_map=<channel map>");
> +        "channel_map=<channel map> "
> +        "autosuspend=<boolean>");
>   
>   #define DEFAULT_FILE_NAME "/tmp/music.input"
>   #define DEFAULT_SOURCE_NAME "fifo_input"
>   
> +struct pipe_source_msg {
> +    pa_msgobject parent;
> +};
> +
> +typedef struct pipe_source_msg pipe_source_msg;
> +PA_DEFINE_PRIVATE_CLASS(pipe_source_msg, pa_msgobject);
> +
> +enum {
> +    PIPE_SOURCE_SUSPEND,
> +    PIPE_SOURCE_RESUME
> +};
> +
>   struct userdata {
>       pa_core *core;
>       pa_module *module;
> @@ -71,12 +85,14 @@ struct userdata {
>       pa_thread_mq thread_mq;
>       pa_rtpoll *rtpoll;
>   
> +    pipe_source_msg *msg;
> +    pa_usec_t timestamp;
> +    bool autosuspend;
> +    size_t pipe_size;
> +
>       char *filename;
> +    int corkfd;
>       int fd;
> -
> -    pa_memchunk memchunk;
> -
> -    pa_rtpoll_item *rtpoll_item;
>   };
>   
>   static const char* const valid_modargs[] = {
> @@ -87,9 +103,41 @@ static const char* const valid_modargs[] = {
>       "rate",
>       "channels",
>       "channel_map",
> +    "autosuspend",
>       NULL
>   };
>   
> +/* Called from main context */
> +static int pipe_source_process_msg(
> +        pa_msgobject *o,
> +        int code,
> +        void *data,
> +        int64_t offset,
> +        pa_memchunk *chunk) {
> +
> +    struct userdata *u = (struct userdata *) data;
> +
> +    pa_assert(u);
> +
> +    switch (code) {
> +        case PIPE_SOURCE_SUSPEND:
> +            pa_log_debug("Suspending source %s because no writers left", u->source->name);
> +            pa_source_suspend(u->source, true, PA_SUSPEND_APPLICATION);
> +            break;
> +
> +        case PIPE_SOURCE_RESUME:
> +            pa_log_debug("Resuming source %s", u->source->name);
> +            pa_source_suspend(u->source, false, PA_SUSPEND_APPLICATION);
> +            break;
> +
> +        default:
> +            pa_assert_not_reached();
> +    }
> +
> +    return 0;
> +}
> +
> +/* Called from thread context */
>   static int source_process_msg(
>           pa_msgobject *o,
>           int code,
> @@ -101,17 +149,19 @@ static int source_process_msg(
>   
>       switch (code) {
>   
> -        case PA_SOURCE_MESSAGE_GET_LATENCY: {
> -            size_t n = 0;
> +        case PA_SOURCE_MESSAGE_SET_STATE:
>   
> -#ifdef FIONREAD
> -            int l;
> +            if (u->source->thread_info.state == PA_SOURCE_SUSPENDED || u->source->thread_info.state == PA_SOURCE_INIT) {
> +                if (PA_SOURCE_IS_OPENED(PA_PTR_TO_UINT(data)))
> +                    u->timestamp = pa_rtclock_now();
> +            }
>   
> -            if (ioctl(u->fd, FIONREAD, &l) >= 0 && l > 0)
> -                n = (size_t) l;
> -#endif
> +            break;
> +
> +        case PA_SOURCE_MESSAGE_GET_LATENCY: {
> +
> +            *((int64_t*) data) = PA_CLIP_SUB((int64_t)pa_rtclock_now(), (int64_t)u->timestamp);
>   
> -            *((int64_t*) data) = pa_bytes_to_usec(n, &u->source->sample_spec);
>               return 0;
>           }
>       }
> @@ -121,7 +171,11 @@ static int source_process_msg(
>   
>   static void thread_func(void *userdata) {
>       struct userdata *u = userdata;
> +    pa_rtpoll_item *rtpoll_item;
> +    struct pollfd *pollfd;
> +    pa_memchunk chunk;
>       int read_type = 0;
> +    size_t fs;
>   
>       pa_assert(u);
>   
> @@ -129,68 +183,140 @@ static void thread_func(void *userdata) {
>   
>       pa_thread_mq_install(&u->thread_mq);
>   
> +    fs = pa_frame_size(&u->source->sample_spec);
> +
> +    pa_memchunk_reset(&chunk);
> +    chunk.memblock = pa_memblock_new(u->core->mempool, u->pipe_size);
> +
> +    rtpoll_item = NULL;
> +    pollfd = NULL;
> +
> +    u->timestamp = pa_rtclock_now();
> +
> +    /* Close our writer here to suspend source if no writers left */
> +    pa_assert_se(pa_close(u->corkfd) == 0);
> +    u->corkfd = -1;
> +
>       for (;;) {
>           int ret;
> -        struct pollfd *pollfd;
>   
> -        pollfd = pa_rtpoll_item_get_pollfd(u->rtpoll_item, NULL);
> +        if (chunk.length) {
> +            /* We have a pending data, let's stop polling pipe.
> +             * Setting up pollfd->events = 0 is not enough to stop
> +             * POLLHUP spam if all writers are closed pipe.
> +             * We need to stop polling pipe completely */
> +            if (rtpoll_item) {
> +                pa_rtpoll_item_free(rtpoll_item);
> +                rtpoll_item = NULL;
> +            }
> +        } else {
> +            /* We have no pending data, let's start polling pipe */
> +            if (rtpoll_item == NULL) {
> +                rtpoll_item = pa_rtpoll_item_new(u->rtpoll, PA_RTPOLL_NEVER, 1);
> +                pollfd = pa_rtpoll_item_get_pollfd(rtpoll_item, NULL);
> +                pollfd->events = POLLIN;
> +                pollfd->fd = u->fd;
> +            }
> +        }

Your code will allocate/deallocate the rtpoll_item on each
iteration. This is unnecessary and CPU intensive (I was told).
I would still prefer my approach and I only see disadvantages
with your way.

>   
> -        /* Try to read some data and pass it on to the source driver */
> -        if (u->source->thread_info.state == PA_SOURCE_RUNNING && pollfd->revents) {
> -            ssize_t l;
> -            void *p;
> +        if ((ret = pa_rtpoll_run(u->rtpoll)) < 0)
> +            goto fail;
>   
> -            if (!u->memchunk.memblock) {
> -                u->memchunk.memblock = pa_memblock_new(u->core->mempool, pa_pipe_buf(u->fd));
> -                u->memchunk.index = u->memchunk.length = 0;
> -            }
> +        if (ret == 0)
> +            goto finish;
>   
> -            pa_assert(pa_memblock_get_length(u->memchunk.memblock) > u->memchunk.index);
> +        if (rtpoll_item) {
> +            pollfd = pa_rtpoll_item_get_pollfd(rtpoll_item, NULL);
>   
> -            p = pa_memblock_acquire(u->memchunk.memblock);
> -            l = pa_read(u->fd, (uint8_t*) p + u->memchunk.index, pa_memblock_get_length(u->memchunk.memblock) - u->memchunk.index, &read_type);
> -            pa_memblock_release(u->memchunk.memblock);
> +            if (pollfd->revents & ~(POLLIN|POLLHUP)) {
> +                pa_log("FD error: %s%s%s%s",
> +                       pollfd->revents & POLLOUT ? "POLLOUT " : "",
> +                       pollfd->revents & POLLERR ? "POLLERR " : "",
> +                       pollfd->revents & POLLPRI ? "POLLPRI " : "",
> +                       pollfd->revents & POLLNVAL ? "POLLNVAL " : "");
>   
> -            pa_assert(l != 0); /* EOF cannot happen, since we opened the fifo for both reading and writing */
> +                goto fail;
> +            }
> +        } else
> +            pollfd = NULL;
>   
> -            if (l < 0) {
> +        /* Try to read some data if there are any events */
> +        if (pollfd && pollfd->revents) {
> +            ssize_t l;
> +            void *p;
>   
> -                if (errno == EINTR)
> -                    continue;
> -                else if (errno != EAGAIN) {
> -                    pa_log("Failed to read data from FIFO: %s", pa_cstrerror(errno));
> -                    goto fail;
> -                }
> +            pa_assert(chunk.index < fs);
>   
> -            } else {
> +            p = pa_memblock_acquire(chunk.memblock);
> +            l = pa_read(u->fd, (uint8_t *) p + chunk.index, pa_memblock_get_length(chunk.memblock) - chunk.index, &read_type);
> +            pa_memblock_release(chunk.memblock);
>   
> -                u->memchunk.length = (size_t) l;
> -                pa_source_post(u->source, &u->memchunk);
> -                u->memchunk.index += (size_t) l;
> +            if (l > 0) {
> +                chunk.length = (size_t) l;
> +                u->timestamp = pa_rtclock_now();
>   
> -                if (u->memchunk.index >= pa_memblock_get_length(u->memchunk.memblock)) {
> -                    pa_memblock_unref(u->memchunk.memblock);
> -                    pa_memchunk_reset(&u->memchunk);
> +                if (u->corkfd >= 0) {
> +                    if (u->autosuspend)
> +                        pa_asyncmsgq_post(pa_thread_mq_get()->outq, PA_MSGOBJECT(u->msg), PIPE_SOURCE_RESUME, u, 0, NULL, NULL);
> +
> +                    pa_assert_se(pa_close(u->corkfd) == 0);
> +                    u->corkfd = -1;
> +                }
> +            } else if (l == 0) {
> +                /* Writer was disconnected: discard unalligned data tail */
> +                chunk.index = 0;
> +
> +                if (u->corkfd < 0) {
> +                    if (u->autosuspend)
> +                        pa_asyncmsgq_post(pa_thread_mq_get()->outq, PA_MSGOBJECT(u->msg), PIPE_SOURCE_SUSPEND, u, 0, NULL, NULL);
> +
> +                    if ((u->corkfd = pa_open_cloexec(u->filename, O_WRONLY, 0)) < 0) {
> +                        pa_log("open('%s'): %s", u->filename, pa_cstrerror(errno));
> +                        goto fail;
> +                    }
>                   }
> +            } else {
> +                if (errno == EINTR || errno == EAGAIN)
> +                    continue;
>   
> -                pollfd->revents = 0;
> +                pa_log("Failed to read data from FIFO: %s", pa_cstrerror(errno));
> +                goto fail;
>               }
>           }
>   
> -        /* Hmm, nothing to do. Let's sleep */
> -        pollfd->events = (short) (u->source->thread_info.state == PA_SOURCE_RUNNING ? POLLIN : 0);
> +        /* Post pending data.
> +         * Let's keep frame boundaries */
> +        if (PA_SOURCE_IS_OPENED(u->source->thread_info.state)) {

Just checking if the source is open before you post the data is also not
the right thing to do. When you are resuming from autosuspend, you
send a message to the main thread. You do not know if this message
has already been processed when you reach this part of the code.

> +            size_t total_len = chunk.index + chunk.length;
> +            size_t frames = total_len / fs;
> +            size_t tail = total_len % fs;
>   
> -        if ((ret = pa_rtpoll_run(u->rtpoll)) < 0)
> -            goto fail;
> +            if (frames > 0) {
> +                pa_memblock *memblock;
>   
> -        if (ret == 0)
> -            goto finish;
> +                memblock = pa_memblock_new(u->core->mempool, u->pipe_size);
> +                chunk.length = frames * fs;
> +                chunk.index = 0;
>   
> -        pollfd = pa_rtpoll_item_get_pollfd(u->rtpoll_item, NULL);
> +                if (tail) {
> +                    void *src, *dst;
>   
> -        if (pollfd->revents & ~POLLIN) {
> -            pa_log("FIFO shutdown.");
> -            goto fail;
> +                    dst = pa_memblock_acquire(memblock);
> +                    src = pa_memblock_acquire(chunk.memblock);
> +
> +                    memcpy(dst, (uint8_t *) src + chunk.length, tail);
> +
> +                    pa_memblock_release(chunk.memblock);
> +                    pa_memblock_release(memblock);
> +                }
> +
> +                pa_source_post(u->source, &chunk);
> +                pa_memblock_unref(chunk.memblock);
> +                chunk.memblock = memblock;
> +            }
> +
> +            chunk.index = tail;
> +            chunk.length = 0;
>           }
>       }
>   
> @@ -201,6 +327,11 @@ fail:
>       pa_asyncmsgq_wait_for(u->thread_mq.inq, PA_MESSAGE_SHUTDOWN);
>   
>   finish:
> +    if (rtpoll_item)
> +        pa_rtpoll_item_free(rtpoll_item);
> +
> +    pa_memblock_unref(chunk.memblock);
> +
>       pa_log_debug("Thread shutting down");
>   }
>   
> @@ -210,7 +341,6 @@ int pa__init(pa_module *m) {
>       pa_sample_spec ss;
>       pa_channel_map map;
>       pa_modargs *ma;
> -    struct pollfd *pollfd;
>       pa_source_new_data data;
>   
>       pa_assert(m);
> @@ -230,7 +360,6 @@ int pa__init(pa_module *m) {
>       m->userdata = u = pa_xnew0(struct userdata, 1);
>       u->core = m->core;
>       u->module = m;
> -    pa_memchunk_reset(&u->memchunk);
>       u->rtpoll = pa_rtpoll_new();
>   
>       if (pa_thread_mq_init(&u->thread_mq, m->core->mainloop, u->rtpoll) < 0) {
> @@ -238,13 +367,31 @@ int pa__init(pa_module *m) {
>           goto fail;
>       }
>   
> +    if (!(u->msg = pa_msgobject_new(pipe_source_msg)))
> +        goto fail;
> +
> +    u->msg->parent.process_msg = pipe_source_process_msg;
> +
> +    u->autosuspend = true;
> +
> +    if (pa_modargs_get_value_boolean(ma, "autosuspend", &u->autosuspend) < 0) {
> +        pa_log("Failed to parse autosuspend argument.");
> +        goto fail;
> +    }
> +
>       u->filename = pa_runtime_path(pa_modargs_get_value(ma, "file", DEFAULT_FILE_NAME));
>   
>       if (mkfifo(u->filename, 0666) < 0) {
>           pa_log("mkfifo('%s'): %s", u->filename, pa_cstrerror(errno));
>           goto fail;
>       }
> -    if ((u->fd = pa_open_cloexec(u->filename, O_RDWR, 0)) < 0) {
> +
> +    if ((u->corkfd = pa_open_cloexec(u->filename, O_RDWR, 0)) < 0) {
> +        pa_log("open('%s'): %s", u->filename, pa_cstrerror(errno));
> +        goto fail;
> +    }
> +
> +    if ((u->fd = pa_open_cloexec(u->filename, O_RDONLY, 0)) < 0) {
>           pa_log("open('%s'): %s", u->filename, pa_cstrerror(errno));
>           goto fail;
>       }
> @@ -289,12 +436,10 @@ int pa__init(pa_module *m) {
>   
>       pa_source_set_asyncmsgq(u->source, u->thread_mq.inq);
>       pa_source_set_rtpoll(u->source, u->rtpoll);
> -    pa_source_set_fixed_latency(u->source, pa_bytes_to_usec(pa_pipe_buf(u->fd), &u->source->sample_spec));
>   
> -    u->rtpoll_item = pa_rtpoll_item_new(u->rtpoll, PA_RTPOLL_NEVER, 1);
> -    pollfd = pa_rtpoll_item_get_pollfd(u->rtpoll_item, NULL);
> -    pollfd->fd = u->fd;
> -    pollfd->events = pollfd->revents = 0;
> +    u->pipe_size = pa_pipe_buf(u->fd);
> +    u->pipe_size = PA_MIN(pa_mempool_block_size_max(u->core->mempool), u->pipe_size);
> +    pa_source_set_fixed_latency(u->source, pa_bytes_to_usec(u->pipe_size, &u->source->sample_spec));
>   
>       if (!(u->thread = pa_thread_new("pipe-source", thread_func, u))) {
>           pa_log("Failed to create thread.");
> @@ -346,12 +491,6 @@ void pa__done(pa_module *m) {
>       if (u->source)
>           pa_source_unref(u->source);
>   
> -    if (u->memchunk.memblock)
> -        pa_memblock_unref(u->memchunk.memblock);
> -
> -    if (u->rtpoll_item)
> -        pa_rtpoll_item_free(u->rtpoll_item);
> -
>       if (u->rtpoll)
>           pa_rtpoll_free(u->rtpoll);
>   
> @@ -360,6 +499,12 @@ void pa__done(pa_module *m) {
>           pa_xfree(u->filename);
>       }
>   
> +    if (u->msg)
> +        pa_xfree(u->msg);
> +
> +    if (u->corkfd >= 0)
> +        pa_assert_se(pa_close(u->corkfd) == 0);
> +
>       if (u->fd >= 0)
>           pa_assert_se(pa_close(u->fd) == 0);
>   




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