void lib_ring_buffer_backend_reset(struct lttng_ust_lib_ring_buffer_backend *bufb,
struct lttng_ust_shm_handle *handle)
{
struct channel_backend *chanb;
const struct lttng_ust_lib_ring_buffer_config *config;
unsigned long num_subbuf_alloc;
unsigned int i;
chanb = &shmp(handle, bufb->chan)->backend;
if (!chanb)
abort();
config = &chanb->config;
num_subbuf_alloc = chanb->num_subbuf;
if (chanb->extra_reader_sb)
num_subbuf_alloc++;
for (i = 0; i < chanb->num_subbuf; i++) {
struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb;
sb = shmp_index(handle, bufb->buf_wsb, i);
if (!sb)
abort();
sb->id = subbuffer_id(config, 0, 1, i);
}
if (chanb->extra_reader_sb)
bufb->buf_rsb.id = subbuffer_id(config, 0, 1,
num_subbuf_alloc - 1);
else
bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0);
for (i = 0; i < num_subbuf_alloc; i++) {
struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp;
struct lttng_ust_lib_ring_buffer_backend_pages *pages;
sbp = shmp_index(handle, bufb->array, i);
if (!sbp)
abort();
pages = shmp(handle, sbp->shmp);
if (!pages)
abort();
/* Don't reset mmap_offset */
v_set(config, &pages->records_commit, 0);
v_set(config, &pages->records_unread, 0);
pages->data_size = 0;
/* Don't reset backend page and virt addresses */
}
/* Don't reset num_pages_per_subbuf, cpu, allocated */
v_set(config, &bufb->records_read, 0);
}
/* returns the offset of the subbuffer belonging to the mmap reader. */
int ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
{
struct channel *chan = handle->shadow_chan;
unsigned long sb_bindex;
if (!handle || !buf || !off)
return -EINVAL;
if (chan->backend.config.output != RING_BUFFER_MMAP)
return -EINVAL;
sb_bindex = subbuffer_id_get_index(&chan->backend.config,
buf->backend.buf_rsb.id);
*off = shmp(handle, shmp_index(handle, buf->backend.array, sb_bindex)->shmp)->mmap_offset;
return 0;
}
/* returns the offset of the subbuffer belonging to the mmap reader. */
int ustctl_get_mmap_read_offset(struct ustctl_consumer_stream *stream,
unsigned long *off)
{
struct channel *chan;
unsigned long sb_bindex;
struct lttng_ust_lib_ring_buffer *buf;
struct ustctl_consumer_channel *consumer_chan;
if (!stream)
return -EINVAL;
buf = stream->buf;
consumer_chan = stream->chan;
chan = consumer_chan->chan->chan;
if (chan->backend.config.output != RING_BUFFER_MMAP)
return -EINVAL;
sb_bindex = subbuffer_id_get_index(&chan->backend.config,
buf->backend.buf_rsb.id);
*off = shmp(consumer_chan->chan->handle,
shmp_index(consumer_chan->chan->handle, buf->backend.array, sb_bindex)->shmp)->mmap_offset;
return 0;
}
/**
* lib_ring_buffer_backend_allocate - allocate a channel buffer
* @config: ring buffer instance configuration
* @buf: the buffer struct
* @size: total size of the buffer
* @num_subbuf: number of subbuffers
* @extra_reader_sb: need extra subbuffer for reader
*/
static
int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_config *config,
struct lttng_ust_lib_ring_buffer_backend *bufb,
size_t size, size_t num_subbuf,
int extra_reader_sb,
struct lttng_ust_shm_handle *handle,
struct shm_object *shmobj)
{
struct channel_backend *chanb;
unsigned long subbuf_size, mmap_offset = 0;
unsigned long num_subbuf_alloc;
unsigned long i;
long page_size;
chanb = &shmp(handle, bufb->chan)->backend;
if (!chanb)
return -EINVAL;
subbuf_size = chanb->subbuf_size;
num_subbuf_alloc = num_subbuf;
if (extra_reader_sb)
num_subbuf_alloc++;
page_size = sysconf(_SC_PAGE_SIZE);
if (page_size <= 0) {
goto page_size_error;
}
align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp));
set_shmp(bufb->array, zalloc_shm(shmobj,
sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc));
if (caa_unlikely(!shmp(handle, bufb->array)))
goto array_error;
/*
* This is the largest element (the buffer pages) which needs to
* be aligned on page size.
*/
align_shm(shmobj, page_size);
set_shmp(bufb->memory_map, zalloc_shm(shmobj,
subbuf_size * num_subbuf_alloc));
if (caa_unlikely(!shmp(handle, bufb->memory_map)))
goto memory_map_error;
/* Allocate backend pages array elements */
for (i = 0; i < num_subbuf_alloc; i++) {
align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages));
set_shmp(shmp_index(handle, bufb->array, i)->shmp,
zalloc_shm(shmobj,
sizeof(struct lttng_ust_lib_ring_buffer_backend_pages)));
if (!shmp(handle, shmp_index(handle, bufb->array, i)->shmp))
goto free_array;
}
/* Allocate write-side subbuffer table */
align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer));
set_shmp(bufb->buf_wsb, zalloc_shm(shmobj,
sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer)
* num_subbuf));
if (caa_unlikely(!shmp(handle, bufb->buf_wsb)))
goto free_array;
for (i = 0; i < num_subbuf; i++) {
struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb;
sb = shmp_index(handle, bufb->buf_wsb, i);
if (!sb)
goto free_array;
sb->id = subbuffer_id(config, 0, 1, i);
}
/* Assign read-side subbuffer table */
if (extra_reader_sb)
bufb->buf_rsb.id = subbuffer_id(config, 0, 1,
num_subbuf_alloc - 1);
else
bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0);
/* Allocate subbuffer packet counter table */
align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer));
set_shmp(bufb->buf_cnt, zalloc_shm(shmobj,
sizeof(struct lttng_ust_lib_ring_buffer_backend_counts)
* num_subbuf));
if (caa_unlikely(!shmp(handle, bufb->buf_cnt)))
goto free_wsb;
/* Assign pages to page index */
for (i = 0; i < num_subbuf_alloc; i++) {
struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp;
struct lttng_ust_lib_ring_buffer_backend_pages *pages;
struct shm_ref ref;
ref.index = bufb->memory_map._ref.index;
ref.offset = bufb->memory_map._ref.offset;
ref.offset += i * subbuf_size;
sbp = shmp_index(handle, bufb->array, i);
if (!sbp)
goto free_array;
pages = shmp(handle, sbp->shmp);
if (!pages)
goto free_array;
set_shmp(pages->p, ref);
if (config->output == RING_BUFFER_MMAP) {
pages->mmap_offset = mmap_offset;
mmap_offset += subbuf_size;
}
}
return 0;
free_wsb:
/* bufb->buf_wsb will be freed by shm teardown */
free_array:
/* bufb->array[i] will be freed by shm teardown */
memory_map_error:
/* bufb->array will be freed by shm teardown */
array_error:
page_size_error:
return -ENOMEM;
}
