start implementing sharing of buffer info

[ust.git] / libtracing / relay.c

diff --git a/libtracing/relay.c b/libtracing/relay.c
index 88bdfefc487d5dae3239aa38984a5a6c5150dbbe..2087bcd98a9294b163ea7619353f58996a14ae53 100644 (file)
--- a/libtracing/relay.c
+++ b/libtracing/relay.c
@@ -92,8 +92,8 @@ static struct dentry *ltt_create_buf_file_callback(struct rchan_buf *buf);
 
 static int relay_alloc_buf(struct rchan_buf *buf, size_t *size)
 {
-       unsigned int n_pages;
-       struct buf_page *buf_page, *n;
+//ust//        unsigned int n_pages;
+//ust//        struct buf_page *buf_page, *n;
 
        void *ptr;
        int result;
@@ -1512,6 +1512,48 @@ static void ltt_relay_destroy_buffer(struct ltt_channel_struct *ltt_chan)
 //ust//        wake_up_interruptible(&trace->kref_wq);
 }
 
+static void ltt_chan_alloc_ltt_buf(struct ltt_channel_struct *ltt_chan)
+{
+       void *ptr;
+       int result;
+
+       /* Get one page */
+       size_t size = PAGE_ALIGN(1);
+
+       result = ltt_chan->buf_shmid = shmget(getpid(), size, IPC_CREAT | IPC_EXCL | 0700);
+       if(ltt_chan->buf_shmid == -1) {
+               PERROR("shmget");
+               return -1;
+       }
+
+       ptr = shmat(ltt_chan->buf_shmid, NULL, 0);
+       if(ptr == (void *) -1) {
+               perror("shmat");
+               goto destroy_shmem;
+       }
+
+       /* Already mark the shared memory for destruction. This will occur only
+         * when all users have detached.
+        */
+       result = shmctl(ltt_chan->buf_shmid, IPC_RMID, NULL);
+       if(result == -1) {
+               perror("shmctl");
+               return -1;
+       }
+
+       ltt_chan->buf = ptr;
+
+       return 0;
+
+       destroy_shmem:
+       result = shmctl(ltt_chan->buf_shmid, IPC_RMID, NULL);
+       if(result == -1) {
+               perror("shmctl");
+       }
+
+       return -1;
+}
+
 /*
  * Create channel.
  */
@@ -1546,7 +1588,10 @@ static int ltt_relay_create_channel(const char *trace_name,
        ltt_chan->n_subbufs_order = get_count_order(n_subbufs);
        ltt_chan->commit_count_mask = (~0UL >> ltt_chan->n_subbufs_order);
 //ust//        ltt_chan->buf = percpu_alloc_mask(sizeof(struct ltt_channel_buf_struct), GFP_KERNEL, cpu_possible_map);
-       ltt_chan->buf = malloc(sizeof(struct ltt_channel_buf_struct));
+
+       ltt_chan_alloc_ltt_buf(ltt_chan);
+
+//ust//        ltt_chan->buf = malloc(sizeof(struct ltt_channel_buf_struct));
        if (!ltt_chan->buf)
                goto alloc_error;
        ltt_chan->trans_channel_data = ltt_relay_open(tmpname,