Ring buffer: use shmp (shared-memory pointers) for per-channel shm structures

[lttng-ust.git] / libringbuffer / backend_internal.h

diff --git a/libringbuffer/backend_internal.h b/libringbuffer/backend_internal.h
index c5f3362e53ed03c21267e635e5242a6c7299ccec..182ac97c6d72d3163d2c88be9f7a312d640f9473 100644 (file)
--- a/libringbuffer/backend_internal.h
+++ b/libringbuffer/backend_internal.h
@@ -17,20 +17,22 @@
 #include "config.h"
 #include "backend_types.h"
 #include "frontend_types.h"
+#include "shm.h"
 
 /* Ring buffer backend API presented to the frontend */
 
 /* Ring buffer and channel backend create/free */
 
 int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb,
-                                  struct channel_backend *chan, int cpu);
+                                  struct channel_backend *chan, int cpu,
+                                  struct shm_header *shm_header);
 void channel_backend_unregister_notifiers(struct channel_backend *chanb);
 void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb);
 int channel_backend_init(struct channel_backend *chanb,
                         const char *name,
                         const struct lib_ring_buffer_config *config,
                         void *priv, size_t subbuf_size,
-                        size_t num_subbuf);
+                        size_t num_subbuf, struct shm_header *shm_header);
 void channel_backend_free(struct channel_backend *chanb);
 
 void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb);
@@ -185,8 +187,8 @@ void subbuffer_count_record(const struct lib_ring_buffer_config *config,
 {
        unsigned long sb_bindex;
 
-       sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
-       v_inc(config, &bufb->array[sb_bindex]->records_commit);
+       sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
+       v_inc(config, &shmp(bufb->array)[sb_bindex]->records_commit);
 }
 
 /*
@@ -201,9 +203,9 @@ void subbuffer_consume_record(const struct lib_ring_buffer_config *config,
 
        sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id);
        CHAN_WARN_ON(bufb->chan,
-                    !v_read(config, &bufb->array[sb_bindex]->records_unread));
+                    !v_read(config, &shmp(bufb->array)[sb_bindex]->records_unread));
        /* Non-atomic decrement protected by exclusive subbuffer access */
-       _v_dec(config, &bufb->array[sb_bindex]->records_unread);
+       _v_dec(config, &shmp(bufb->array)[sb_bindex]->records_unread);
        v_inc(config, &bufb->records_read);
 }
 
@@ -215,8 +217,8 @@ unsigned long subbuffer_get_records_count(
 {
        unsigned long sb_bindex;
 
-       sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
-       return v_read(config, &bufb->array[sb_bindex]->records_commit);
+       sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
+       return v_read(config, &shmp(bufb->array)[sb_bindex]->records_commit);
 }
 
 /*
@@ -234,8 +236,8 @@ unsigned long subbuffer_count_records_overrun(
        struct lib_ring_buffer_backend_pages *pages;
        unsigned long overruns, sb_bindex;
 
-       sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
-       pages = bufb->array[sb_bindex];
+       sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
+       pages = shmp(bufb->array)[sb_bindex];
        overruns = v_read(config, &pages->records_unread);
        v_set(config, &pages->records_unread,
              v_read(config, &pages->records_commit));
@@ -253,8 +255,8 @@ void subbuffer_set_data_size(const struct lib_ring_buffer_config *config,
        struct lib_ring_buffer_backend_pages *pages;
        unsigned long sb_bindex;
 
-       sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
-       pages = bufb->array[sb_bindex];
+       sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
+       pages = shmp(bufb->array)[sb_bindex];
        pages->data_size = data_size;
 }
 
@@ -267,7 +269,7 @@ unsigned long subbuffer_get_read_data_size(
        unsigned long sb_bindex;
 
        sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id);
-       pages = bufb->array[sb_bindex];
+       pages = shmp(bufb->array)[sb_bindex];
        return pages->data_size;
 }
 
@@ -280,8 +282,8 @@ unsigned long subbuffer_get_data_size(
        struct lib_ring_buffer_backend_pages *pages;
        unsigned long sb_bindex;
 
-       sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
-       pages = bufb->array[sb_bindex];
+       sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
+       pages = shmp(bufb->array)[sb_bindex];
        return pages->data_size;
 }
 
@@ -303,7 +305,7 @@ void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config,
         * Performing a volatile access to read the sb_pages, because we want to
         * read a coherent version of the pointer and the associated noref flag.
         */
-       id = CMM_ACCESS_ONCE(bufb->buf_wsb[idx].id);
+       id = CMM_ACCESS_ONCE(shmp(bufb->buf_wsb)[idx].id);
        for (;;) {
                /* This check is called on the fast path for each record. */
                if (likely(!subbuffer_id_is_noref(config, id))) {
@@ -317,7 +319,7 @@ void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config,
                }
                new_id = id;
                subbuffer_id_clear_noref(config, &new_id);
-               new_id = uatomic_cmpxchg(&bufb->buf_wsb[idx].id, id, new_id);
+               new_id = uatomic_cmpxchg(&shmp(bufb->buf_wsb)[idx].id, id, new_id);
                if (likely(new_id == id))
                        break;
                id = new_id;
@@ -348,13 +350,13 @@ void lib_ring_buffer_set_noref_offset(const struct lib_ring_buffer_config *confi
         * readers of the noref flag.
         */
        CHAN_WARN_ON(bufb->chan,
-                    subbuffer_id_is_noref(config, bufb->buf_wsb[idx].id));
+                    subbuffer_id_is_noref(config, shmp(bufb->buf_wsb)[idx].id));
        /*
         * Memory barrier that ensures counter stores are ordered before set
         * noref and offset.
         */
        cmm_smp_mb();
-       subbuffer_id_set_noref_offset(config, &bufb->buf_wsb[idx].id, offset);
+       subbuffer_id_set_noref_offset(config, &shmp(bufb->buf_wsb)[idx].id, offset);
 }
 
 /**
@@ -376,7 +378,7 @@ int update_read_sb_index(const struct lib_ring_buffer_config *config,
                 * old_wpage, because the value read will be confirmed by the
                 * following cmpxchg().
                 */
-               old_id = bufb->buf_wsb[consumed_idx].id;
+               old_id = shmp(bufb->buf_wsb)[consumed_idx].id;
                if (unlikely(!subbuffer_id_is_noref(config, old_id)))
                        return -EAGAIN;
                /*
@@ -390,14 +392,14 @@ int update_read_sb_index(const struct lib_ring_buffer_config *config,
                             !subbuffer_id_is_noref(config, bufb->buf_rsb.id));
                subbuffer_id_set_noref_offset(config, &bufb->buf_rsb.id,
                                              consumed_count);
-               new_id = uatomic_cmpxchg(&bufb->buf_wsb[consumed_idx].id, old_id,
+               new_id = uatomic_cmpxchg(&shmp(bufb->buf_wsb)[consumed_idx].id, old_id,
                                 bufb->buf_rsb.id);
                if (unlikely(old_id != new_id))
                        return -EAGAIN;
                bufb->buf_rsb.id = new_id;
        } else {
                /* No page exchange, use the writer page directly */
-               bufb->buf_rsb.id = bufb->buf_wsb[consumed_idx].id;
+               bufb->buf_rsb.id = shmp(bufb->buf_wsb)[consumed_idx].id;
        }
        return 0;
 }