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shmem: unmap regions lazily on closing

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This commit is contained in:
Georg Reinke 2017-07-28 12:17:37 +02:00
parent 29e4facc17
commit 5d156e867c
2 changed files with 36 additions and 6 deletions
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1
include/villas/shmem.h
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@ -73,6 +73,7 @@ struct shmem_dir {
/** Main structure representing the shared memory interface. */
struct shmem_int {
struct shmem_dir read, write;
atomic_int readers, writers, closed;
};
/** Open the shared memory objects and retrieve / initialize the shared data structures.

41
lib/shmem.c
View file

@ -138,6 +138,10 @@ int shmem_int_open(const char *wname, const char* rname, struct shmem_int *shm,
shm->read.len = len;
shm->read.shared = shared;
shm->readers = 0;
shm->writers = 0;
shm->closed = 0;
/* Unlink the semaphores; we don't need them anymore */
sem_unlink(wname);
@ -146,28 +150,53 @@ int shmem_int_open(const char *wname, const char* rname, struct shmem_int *shm,
int shmem_int_close(struct shmem_int *shm)
{
atomic_store(&shm->closed, 1);
if (shm->write.shared->polling)
queue_close(&shm->write.shared->queue.q);
else
queue_signalled_close(&shm->write.shared->queue.qs);
munmap(shm->read.base, shm->read.len);
munmap(shm->write.base, shm->write.len);
shm_unlink(shm->write.name);
if (atomic_load(&shm->readers) == 0)
munmap(shm->read.base, shm->read.len);
if (atomic_load(&shm->writers) == 0)
munmap(shm->write.base, shm->write.len);
return 0;
}
int shmem_int_read(struct shmem_int *shm, struct sample *smps[], unsigned cnt)
{
return shm->read.shared->polling ? queue_pull_many(&shm->read.shared->queue.q, (void **) smps, cnt)
: queue_signalled_pull_many(&shm->read.shared->queue.qs, (void **) smps, cnt);
int ret;
atomic_fetch_add(&shm->readers, 1);
if (shm->read.shared->polling)
ret = queue_pull_many(&shm->read.shared->queue.q, (void **) smps, cnt);
else
ret = queue_signalled_pull_many(&shm->read.shared->queue.qs, (void **) smps, cnt);
if (atomic_fetch_sub(&shm->readers, 1) == 1 && atomic_load(&shm->closed) == 1)
munmap(shm->read.base, shm->read.len);
return ret;
}
int shmem_int_write(struct shmem_int *shm, struct sample *smps[], unsigned cnt)
{
return shm->write.shared->polling ? queue_push_many(&shm->write.shared->queue.q, (void **) smps, cnt)
: queue_signalled_push_many(&shm->write.shared->queue.qs, (void **) smps, cnt);
int ret;
atomic_fetch_add(&shm->writers, 1);
if (shm->write.shared->polling)
ret = queue_push_many(&shm->write.shared->queue.q, (void **) smps, cnt);
else
ret = queue_signalled_push_many(&shm->write.shared->queue.qs, (void **) smps, cnt);
if (atomic_fetch_sub(&shm->writers, 1) == 1 && atomic_load(&shm->closed) == 1)
munmap(shm->write.base, shm->write.len);
return ret;
}
int shmem_int_alloc(struct shmem_int *shm, struct sample *smps[], unsigned cnt)