}
}
+/*
+ * Receive end of subbuffer TSC as parameter. It has been read in the
+ * space reservation loop of either reserve or switch, which ensures it
+ * progresses monotonically with event records in the buffer. Therefore,
+ * it ensures that the end timestamp of a subbuffer is <= begin
+ * timestamp of the following subbuffers.
+ */
static inline
void lib_ring_buffer_check_deliver(const struct lttng_ust_lib_ring_buffer_config *config,
struct lttng_ust_lib_ring_buffer *buf,
unsigned long offset,
unsigned long commit_count,
unsigned long idx,
- struct lttng_ust_shm_handle *handle)
+ struct lttng_ust_shm_handle *handle,
+ uint64_t tsc)
{
unsigned long old_commit_count = commit_count
- chan->backend.subbuf_size;
- uint64_t tsc;
/* Check if all commits have been done */
if (caa_unlikely((buf_trunc(offset, chan) >> chan->backend.num_subbuf_order)
* The subbuffer size is least 2 bytes (minimum size: 1 page).
* This guarantees that old_commit_count + 1 != commit_count.
*/
+
+ /*
+ * Order prior updates to reserve count prior to the
+ * commit_cold cc_sb update.
+ */
+ cmm_smp_wmb();
if (caa_likely(v_cmpxchg(config, &shmp_index(handle, buf->commit_cold, idx)->cc_sb,
old_commit_count, old_commit_count + 1)
== old_commit_count)) {
* and any other writer trying to access this subbuffer
* in this state is required to drop records.
*/
- tsc = config->cb.ring_buffer_clock_read(chan);
v_add(config,
subbuffer_get_records_count(config,
&buf->backend,
/* End of exclusive subbuffer access */
v_set(config, &shmp_index(handle, buf->commit_cold, idx)->cc_sb,
commit_count);
+ /*
+ * Order later updates to reserve count after
+ * the commit cold cc_sb update.
+ */
+ cmm_smp_wmb();
lib_ring_buffer_vmcore_check_deliver(config, buf,
commit_count, idx, handle);
unsigned long idx,
unsigned long buf_offset,
unsigned long commit_count,
- size_t slot_size,
struct lttng_ust_shm_handle *handle)
{
- unsigned long offset, commit_seq_old;
+ unsigned long commit_seq_old;
if (config->oops != RING_BUFFER_OOPS_CONSISTENCY)
return;
- offset = buf_offset + slot_size;
-
/*
* subbuf_offset includes commit_count_mask. We can simply
* compare the offsets within the subbuffer without caring about
* buffer full/empty mismatch because offset is never zero here
* (subbuffer header and record headers have non-zero length).
*/
- if (caa_unlikely(subbuf_offset(offset - commit_count, chan)))
+ if (caa_unlikely(subbuf_offset(buf_offset - commit_count, chan)))
return;
commit_seq_old = v_read(config, &shmp_index(handle, buf->commit_hot, idx)->seq);