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Rename struct lib_ring_buffer* to struct lttng_ust_lib_ring_buffer*
[lttng-ust.git] / libringbuffer / frontend_internal.h
diff --git a/libringbuffer/frontend_internal.h b/libringbuffer/frontend_internal.h
index c60affe07d94dd4e549af3c4abc1dbcfc6eb6c3e..1b55cd5dc97365bfc774dc8cd27633cbaae5b3af 100644 (file)
--- a/libringbuffer/frontend_internal.h
+++ b/libringbuffer/frontend_internal.h
@@ -85,8 +85,8 @@ unsigned long subbuf_index(unsigned long offset, struct channel *chan)
 
 #if (CAA_BITS_PER_LONG == 32)
 static inline
-void save_last_tsc(const struct lib_ring_buffer_config *config,
-                  struct lib_ring_buffer *buf, u64 tsc)
+void save_last_tsc(const struct lttng_ust_lib_ring_buffer_config *config,
+                  struct lttng_ust_lib_ring_buffer *buf, u64 tsc)
 {
        if (config->tsc_bits == 0 || config->tsc_bits == 64)
                return;
@@ -98,8 +98,8 @@ void save_last_tsc(const struct lib_ring_buffer_config *config,
 }
 
 static inline
-int last_tsc_overflow(const struct lib_ring_buffer_config *config,
-                     struct lib_ring_buffer *buf, u64 tsc)
+int last_tsc_overflow(const struct lttng_ust_lib_ring_buffer_config *config,
+                     struct lttng_ust_lib_ring_buffer *buf, u64 tsc)
 {
        unsigned long tsc_shifted;
 
@@ -115,8 +115,8 @@ int last_tsc_overflow(const struct lib_ring_buffer_config *config,
 }
 #else
 static inline
-void save_last_tsc(const struct lib_ring_buffer_config *config,
-                  struct lib_ring_buffer *buf, u64 tsc)
+void save_last_tsc(const struct lttng_ust_lib_ring_buffer_config *config,
+                  struct lttng_ust_lib_ring_buffer *buf, u64 tsc)
 {
        if (config->tsc_bits == 0 || config->tsc_bits == 64)
                return;
@@ -125,8 +125,8 @@ void save_last_tsc(const struct lib_ring_buffer_config *config,
 }
 
 static inline
-int last_tsc_overflow(const struct lib_ring_buffer_config *config,
-                     struct lib_ring_buffer *buf, u64 tsc)
+int last_tsc_overflow(const struct lttng_ust_lib_ring_buffer_config *config,
+                     struct lttng_ust_lib_ring_buffer *buf, u64 tsc)
 {
        if (config->tsc_bits == 0 || config->tsc_bits == 64)
                return 0;
@@ -140,17 +140,17 @@ int last_tsc_overflow(const struct lib_ring_buffer_config *config,
 #endif
 
 extern
-int lib_ring_buffer_reserve_slow(struct lib_ring_buffer_ctx *ctx);
+int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx);
 
 extern
-void lib_ring_buffer_switch_slow(struct lib_ring_buffer *buf,
+void lib_ring_buffer_switch_slow(struct lttng_ust_lib_ring_buffer *buf,
                                 enum switch_mode mode,
-                                struct shm_handle *handle);
+                                struct lttng_ust_shm_handle *handle);
 
 /* Buffer write helpers */
 
 static inline
-void lib_ring_buffer_reserve_push_reader(struct lib_ring_buffer *buf,
+void lib_ring_buffer_reserve_push_reader(struct lttng_ust_lib_ring_buffer *buf,
                                         struct channel *chan,
                                         unsigned long offset)
 {
@@ -178,27 +178,27 @@ void lib_ring_buffer_reserve_push_reader(struct lib_ring_buffer *buf,
 }
 
 static inline
-void lib_ring_buffer_vmcore_check_deliver(const struct lib_ring_buffer_config *config,
-                                         struct lib_ring_buffer *buf,
+void lib_ring_buffer_vmcore_check_deliver(const struct lttng_ust_lib_ring_buffer_config *config,
+                                         struct lttng_ust_lib_ring_buffer *buf,
                                          unsigned long commit_count,
                                          unsigned long idx,
-                                         struct shm_handle *handle)
+                                         struct lttng_ust_shm_handle *handle)
 {
        if (config->oops == RING_BUFFER_OOPS_CONSISTENCY)
-               v_set(config, &shmp(handle, buf->commit_hot)[idx].seq, commit_count);
+               v_set(config, &shmp_index(handle, buf->commit_hot, idx)->seq, commit_count);
 }
 
 static inline
-int lib_ring_buffer_poll_deliver(const struct lib_ring_buffer_config *config,
-                                struct lib_ring_buffer *buf,
+int lib_ring_buffer_poll_deliver(const struct lttng_ust_lib_ring_buffer_config *config,
+                                struct lttng_ust_lib_ring_buffer *buf,
                                 struct channel *chan,
-                                struct shm_handle *handle)
+                                struct lttng_ust_shm_handle *handle)
 {
        unsigned long consumed_old, consumed_idx, commit_count, write_offset;
 
        consumed_old = uatomic_read(&buf->consumed);
        consumed_idx = subbuf_index(consumed_old, chan);
-       commit_count = v_read(config, &shmp(handle, buf->commit_cold)[consumed_idx].cc_sb);
+       commit_count = v_read(config, &shmp_index(handle, buf->commit_cold, consumed_idx)->cc_sb);
        /*
         * No memory barrier here, since we are only interested
         * in a statistically correct polling result. The next poll will
@@ -232,18 +232,18 @@ int lib_ring_buffer_poll_deliver(const struct lib_ring_buffer_config *config,
 }
 
 static inline
-int lib_ring_buffer_pending_data(const struct lib_ring_buffer_config *config,
-                                struct lib_ring_buffer *buf,
+int lib_ring_buffer_pending_data(const struct lttng_ust_lib_ring_buffer_config *config,
+                                struct lttng_ust_lib_ring_buffer *buf,
                                 struct channel *chan)
 {
        return !!subbuf_offset(v_read(config, &buf->offset), chan);
 }
 
 static inline
-unsigned long lib_ring_buffer_get_data_size(const struct lib_ring_buffer_config *config,
-                                           struct lib_ring_buffer *buf,
+unsigned long lib_ring_buffer_get_data_size(const struct lttng_ust_lib_ring_buffer_config *config,
+                                           struct lttng_ust_lib_ring_buffer *buf,
                                            unsigned long idx,
-                                           struct shm_handle *handle)
+                                           struct lttng_ust_shm_handle *handle)
 {
        return subbuffer_get_data_size(config, &buf->backend, idx, handle);
 }
@@ -254,10 +254,10 @@ unsigned long lib_ring_buffer_get_data_size(const struct lib_ring_buffer_config
  * This is a very specific ftrace use-case, so we keep this as "internal" API.
  */
 static inline
-int lib_ring_buffer_reserve_committed(const struct lib_ring_buffer_config *config,
-                                     struct lib_ring_buffer *buf,
+int lib_ring_buffer_reserve_committed(const struct lttng_ust_lib_ring_buffer_config *config,
+                                     struct lttng_ust_lib_ring_buffer *buf,
                                      struct channel *chan,
-                                     struct shm_handle *handle)
+                                     struct lttng_ust_shm_handle *handle)
 {
        unsigned long offset, idx, commit_count;
 
@@ -275,7 +275,7 @@ int lib_ring_buffer_reserve_committed(const struct lib_ring_buffer_config *confi
        do {
                offset = v_read(config, &buf->offset);
                idx = subbuf_index(offset, chan);
-               commit_count = v_read(config, &shmp(handle, buf->commit_hot)[idx].cc);
+               commit_count = v_read(config, &shmp_index(handle, buf->commit_hot, idx)->cc);
        } while (offset != v_read(config, &buf->offset));
 
        return ((buf_trunc(offset, chan) >> chan->backend.num_subbuf_order)
@@ -283,13 +283,13 @@ int lib_ring_buffer_reserve_committed(const struct lib_ring_buffer_config *confi
 }
 
 static inline
-void lib_ring_buffer_check_deliver(const struct lib_ring_buffer_config *config,
-                                  struct lib_ring_buffer *buf,
+void lib_ring_buffer_check_deliver(const struct lttng_ust_lib_ring_buffer_config *config,
+                                  struct lttng_ust_lib_ring_buffer *buf,
                                   struct channel *chan,
                                   unsigned long offset,
                                   unsigned long commit_count,
                                   unsigned long idx,
-                                  struct shm_handle *handle)
+                                  struct lttng_ust_shm_handle *handle)
 {
        unsigned long old_commit_count = commit_count
                                         - chan->backend.subbuf_size;
@@ -324,7 +324,7 @@ void lib_ring_buffer_check_deliver(const struct lib_ring_buffer_config *config,
                 * The subbuffer size is least 2 bytes (minimum size: 1 page).
                 * This guarantees that old_commit_count + 1 != commit_count.
                 */
-               if (likely(v_cmpxchg(config, &shmp(handle, buf->commit_cold)[idx].cc_sb,
+               if (likely(v_cmpxchg(config, &shmp_index(handle, buf->commit_cold, idx)->cc_sb,
                                         old_commit_count, old_commit_count + 1)
                           == old_commit_count)) {
                        /*
@@ -367,7 +367,7 @@ void lib_ring_buffer_check_deliver(const struct lib_ring_buffer_config *config,
                         */
                        cmm_smp_mb();
                        /* End of exclusive subbuffer access */
-                       v_set(config, &shmp(handle, buf->commit_cold)[idx].cc_sb,
+                       v_set(config, &shmp_index(handle, buf->commit_cold, idx)->cc_sb,
                              commit_count);
                        lib_ring_buffer_vmcore_check_deliver(config, buf,
                                                 commit_count, idx, handle);
@@ -376,7 +376,8 @@ void lib_ring_buffer_check_deliver(const struct lib_ring_buffer_config *config,
                         * RING_BUFFER_WAKEUP_BY_WRITER wakeup is not lock-free.
                         */
                        if (config->wakeup == RING_BUFFER_WAKEUP_BY_WRITER
-                           && uatomic_read(&buf->active_readers)
+                           && (uatomic_read(&buf->active_readers)
+                               || uatomic_read(&buf->active_shadow_readers))
                            && lib_ring_buffer_poll_deliver(config, buf, chan, handle)) {
                                int wakeup_fd = shm_get_wakeup_fd(handle, &buf->self._ref);
 
@@ -386,6 +387,20 @@ void lib_ring_buffer_check_deliver(const struct lib_ring_buffer_config *config,
                                         * Wake-up the other end by
                                         * writing a null byte in the
                                         * pipe (non-blocking).
+                                        * Important note: Because
+                                        * writing into the pipe is
+                                        * non-blocking (and therefore
+                                        * we allow dropping wakeup
+                                        * data, as long as there is
+                                        * wakeup data present in the
+                                        * pipe buffer to wake up the
+                                        * consumer), the consumer
+                                        * should perform the following
+                                        * sequence for waiting:
+                                        * 1) empty the pipe (reads).
+                                        * 2) check if there is data in
+                                        *    the buffer.
+                                        * 3) wait on the pipe (poll).
                                         */
                                        do {
                                                ret = write(wakeup_fd, "", 1);
@@ -406,14 +421,14 @@ void lib_ring_buffer_check_deliver(const struct lib_ring_buffer_config *config,
  * useful for crash dump.
  */
 static inline
-void lib_ring_buffer_write_commit_counter(const struct lib_ring_buffer_config *config,
-                                         struct lib_ring_buffer *buf,
+void lib_ring_buffer_write_commit_counter(const struct lttng_ust_lib_ring_buffer_config *config,
+                                         struct lttng_ust_lib_ring_buffer *buf,
                                          struct channel *chan,
                                          unsigned long idx,
                                          unsigned long buf_offset,
                                          unsigned long commit_count,
                                          size_t slot_size,
-                                         struct shm_handle *handle)
+                                         struct lttng_ust_shm_handle *handle)
 {
        unsigned long offset, commit_seq_old;
 
@@ -431,18 +446,18 @@ void lib_ring_buffer_write_commit_counter(const struct lib_ring_buffer_config *c
        if (unlikely(subbuf_offset(offset - commit_count, chan)))
                return;
 
-       commit_seq_old = v_read(config, &shmp(handle, buf->commit_hot)[idx].seq);
+       commit_seq_old = v_read(config, &shmp_index(handle, buf->commit_hot, idx)->seq);
        while ((long) (commit_seq_old - commit_count) < 0)
-               commit_seq_old = v_cmpxchg(config, &shmp(handle, buf->commit_hot)[idx].seq,
+               commit_seq_old = v_cmpxchg(config, &shmp_index(handle, buf->commit_hot, idx)->seq,
                                           commit_seq_old, commit_count);
 }
 
-extern int lib_ring_buffer_create(struct lib_ring_buffer *buf,
+extern int lib_ring_buffer_create(struct lttng_ust_lib_ring_buffer *buf,
                                  struct channel_backend *chanb, int cpu,
-                                 struct shm_handle *handle,
+                                 struct lttng_ust_shm_handle *handle,
                                  struct shm_object *shmobj);
-extern void lib_ring_buffer_free(struct lib_ring_buffer *buf,
-                                struct shm_handle *handle);
+extern void lib_ring_buffer_free(struct lttng_ust_lib_ring_buffer *buf,
+                                struct lttng_ust_shm_handle *handle);
 
 /* Keep track of trap nesting inside ring buffer code */
 extern __thread unsigned int lib_ring_buffer_nesting;
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