ust: make lttd work

[ust.git] / libtracing / relay.h

diff --git a/libtracing/relay.h b/libtracing/relay.h
index 1689418342fa5fde75d3a40f409dcd0fbb6c0cfe..cd3baae3f3d180c81dcc585e8d89c1c89e3772e6 100644 (file)
--- a/libtracing/relay.h
+++ b/libtracing/relay.h
@@ -59,7 +59,7 @@ struct rchan_buf {
 //ust//        unsigned int page_count;        /* number of current buffer pages */ 
        unsigned int finalized;         /* buffer has been finalized */ 
 //ust//        unsigned int cpu;               /* this buf's cpu */ 
-       int shmid;
+       int shmid;                      /* the shmid of the buffer data pages */
 } ____cacheline_aligned; 
 
 /*
@@ -335,16 +335,24 @@ struct ltt_channel_buf_struct {
                                         */
        local_t events_lost;
        local_t corrupted_subbuffers;
-       spinlock_t full_lock;           /*
-                                        * buffer full condition spinlock, only
-                                        * for userspace tracing blocking mode
-                                        * synchronization with reader.
-                                        */
+//ust//        spinlock_t full_lock;           /*
+//ust//                                         * buffer full condition spinlock, only
+//ust//                                         * for userspace tracing blocking mode
+//ust//                                         * synchronization with reader.
+//ust//                                         */
 //ust//        wait_queue_head_t write_wait;   /*
 //ust//                                         * Wait queue for blocking user space
 //ust//                                         * writers
 //ust//                                         */
-       atomic_t wakeup_readers;        /* Boolean : wakeup readers waiting ? */
+//ust//        atomic_t wakeup_readers;        /* Boolean : wakeup readers waiting ? */
+       /* one byte is written to this pipe when data is available, in order
+           to wake the consumer */
+       /* portability: Single byte writes must be as quick as possible. The kernel-side
+          buffer must be large enough so the writer doesn't block. From the pipe(7)
+           man page: Since linux 2.6.11, the pipe capacity is 65536 bytes. */
+       int data_ready_fd_write;
+       /* the reading end of the pipe */
+       int data_ready_fd_read;
 } ____cacheline_aligned;
 
 int ltt_do_get_subbuf(struct rchan_buf *buf, struct ltt_channel_buf_struct *ltt_buf, long *pconsumed_old);