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A lot of more work to get the lock-free stuff in place

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git-svn-id: file:///home/lennart/svn/public/pulseaudio/branches/lennart@1474 fefdeb5f-60dc-0310-8127-8f9354f1896f
This commit is contained in:
Lennart Poettering 2007-06-13 22:08:14 +00:00
parent 69115687ad
commit be4a882836
33 changed files with 908 additions and 694 deletions
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69
src/pulsecore/asyncq.c
View file

@ -52,8 +52,8 @@ struct pa_asyncq {
unsigned size;
unsigned read_idx;
unsigned write_idx;
pa_atomic_int_t read_waiting;
pa_atomic_int_t write_waiting;
pa_atomic_t read_waiting, n_read;
pa_atomic_t write_waiting, n_written;
int read_fds[2], write_fds[2];
};
@ -80,6 +80,8 @@ pa_asyncq *pa_asyncq_new(unsigned size) {
l->size = size;
pa_atomic_store(&l->read_waiting, 0);
pa_atomic_store(&l->write_waiting, 0);
pa_atomic_store(&l->n_written, 0);
pa_atomic_store(&l->n_read, 0);
if (pipe(l->read_fds) < 0) {
pa_xfree(l);
@ -131,10 +133,26 @@ int pa_asyncq_push(pa_asyncq*l, void *p, int wait) {
if (!pa_atomic_ptr_cmpxchg(&cells[idx], NULL, p)) {
/* First try failed. Let's wait for changes. */
if (!wait)
if (!wait) {
/* Let's empty the FIFO from old notifications, before we return */
while (pa_atomic_load(&l->n_read) > 0) {
ssize_t r;
int x[20];
errno = 0;
if ((r = read(l->write_fds[0], x, sizeof(x))) <= 0 && errno != EINTR)
return -1;
if (r > 0)
if (pa_atomic_sub(&l->n_read, r) <= r)
break;
}
return -1;
}
/* First try failed. Let's wait for changes. */
_Y;
@ -142,6 +160,7 @@ int pa_asyncq_push(pa_asyncq*l, void *p, int wait) {
for (;;) {
char x[20];
ssize_t r;
_Y;
@ -150,10 +169,13 @@ int pa_asyncq_push(pa_asyncq*l, void *p, int wait) {
_Y;
if (read(l->write_fds[0], x, sizeof(x)) < 0 && errno != EINTR) {
if ((r = read(l->write_fds[0], x, sizeof(x))) < 0 && errno != EINTR) {
pa_atomic_dec(&l->write_waiting);
return -1;
}
if (r > 0)
pa_atomic_sub(&l->n_read, r);
}
_Y;
@ -167,7 +189,8 @@ int pa_asyncq_push(pa_asyncq*l, void *p, int wait) {
if (pa_atomic_load(&l->read_waiting)) {
char x = 'x';
_Y;
write(l->read_fds[1], &x, sizeof(x));
if (write(l->read_fds[1], &x, sizeof(x)) > 0)
pa_atomic_inc(&l->n_written);
}
return 0;
@ -189,8 +212,24 @@ void* pa_asyncq_pop(pa_asyncq*l, int wait) {
/* First try failed. Let's wait for changes. */
if (!wait)
if (!wait) {
/* Let's empty the FIFO from old notifications, before we return */
while (pa_atomic_load(&l->n_written) > 0) {
ssize_t r;
int x[20];
errno = 0;
if ((r = read(l->read_fds[0], x, sizeof(x))) <= 0 && errno != EINTR)
return NULL;
if (r > 0)
if (pa_atomic_sub(&l->n_written, r) <= r)
break;
}
return NULL;
}
_Y;
@ -198,6 +237,7 @@ void* pa_asyncq_pop(pa_asyncq*l, int wait) {
for (;;) {
char x[20];
ssize_t r;
_Y;
@ -206,10 +246,13 @@ void* pa_asyncq_pop(pa_asyncq*l, int wait) {
_Y;
if (read(l->read_fds[0], x, sizeof(x)) < 0 && errno != EINTR) {
if ((r = read(l->read_fds[0], x, sizeof(x)) < 0) && errno != EINTR) {
pa_atomic_dec(&l->read_waiting);
return NULL;
}
if (r > 0)
pa_atomic_sub(&l->n_written, r);
}
_Y;
@ -226,7 +269,8 @@ void* pa_asyncq_pop(pa_asyncq*l, int wait) {
if (pa_atomic_load(&l->write_waiting)) {
char x = 'x';
_Y;
write(l->write_fds[1], &x, sizeof(x));
if (write(l->write_fds[1], &x, sizeof(x)) >= 0)
pa_atomic_inc(&l->n_read);
}
return ret;
@ -262,10 +306,13 @@ int pa_asyncq_before_poll(pa_asyncq *l) {
return 0;
}
int pa_asyncq_after_poll(pa_asyncq *l) {
void pa_asyncq_after_poll(pa_asyncq *l) {
pa_assert(l);
pa_assert(pa_atomic_load(&l->read_waiting) > 0);
pa_atomic_dec(&l->read_waiting);
}