sessiond: notification: synchronize notification client (and list)

[lttng-tools.git] / src / bin / lttng-relayd / tracefile-array.c

diff --git a/src/bin/lttng-relayd/tracefile-array.c b/src/bin/lttng-relayd/tracefile-array.c
index bcbee5c557103b042544f936f82e8d99b12089fd..05ce3ad34520c9f09c7bb91fe2b235684c2a106d 100644 (file)
--- a/src/bin/lttng-relayd/tracefile-array.c
+++ b/src/bin/lttng-relayd/tracefile-array.c
@@ -1,21 +1,10 @@
 /*
- * Copyright (C) 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License, version 2 only, as
- * published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 51
- * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
 #define _LGPL_SOURCE
 #include <assert.h>
 #include <common/common.h>
@@ -63,7 +52,24 @@ void tracefile_array_destroy(struct tracefile_array *tfa)
        free(tfa);
 }
 
-void tracefile_array_file_rotate(struct tracefile_array *tfa)
+void tracefile_array_reset(struct tracefile_array *tfa)
+{
+       size_t count, i;
+
+       count = tfa->count;
+       for (i = 0; i < count; i++) {
+               tfa->tf[i].seq_head = -1ULL;
+               tfa->tf[i].seq_tail = -1ULL;
+       }
+       tfa->seq_head = -1ULL;
+       tfa->seq_tail = -1ULL;
+       tfa->file_head_read = 0;
+       tfa->file_head_write = 0;
+       tfa->file_tail = 0;
+}
+
+void tracefile_array_file_rotate(struct tracefile_array *tfa,
+               enum tracefile_rotate_type type)
 {
        uint64_t *headp, *tailp;
 
@@ -71,42 +77,56 @@ void tracefile_array_file_rotate(struct tracefile_array *tfa)
                /* Not in tracefile rotation mode. */
                return;
        }
-       /* Rotate to next file.  */
-       tfa->file_head = (tfa->file_head + 1) % tfa->count;
-       if (tfa->file_head == tfa->file_tail) {
-               /* Move tail. */
-               tfa->file_tail = (tfa->file_tail + 1) % tfa->count;
-       }
-       headp = &tfa->tf[tfa->file_head].seq_head;
-       tailp = &tfa->tf[tfa->file_head].seq_tail;
-       /*
-        * If we overwrite a file with content, we need to push the tail
-        * to the position following the content we are overwriting.
-        */
-       if (*headp != -1ULL) {
-               tfa->seq_tail = tfa->tf[tfa->file_tail].seq_tail;
+       switch (type) {
+       case TRACEFILE_ROTATE_READ:
+               /*
+                * Rotate read head to write head position, thus allowing
+                * reader to consume the newly rotated head file.
+                */
+               tfa->file_head_read = tfa->file_head_write;
+               break;
+       case TRACEFILE_ROTATE_WRITE:
+               /* Rotate write head to next file, pushing tail if needed.  */
+               tfa->file_head_write = (tfa->file_head_write + 1) % tfa->count;
+               if (tfa->file_head_write == tfa->file_tail) {
+                       /* Move tail. */
+                       tfa->file_tail = (tfa->file_tail + 1) % tfa->count;
+               }
+               headp = &tfa->tf[tfa->file_head_write].seq_head;
+               tailp = &tfa->tf[tfa->file_head_write].seq_tail;
+               /*
+                * If we overwrite a file with content, we need to push the tail
+                * to the position following the content we are overwriting.
+                */
+               if (*headp != -1ULL) {
+                       tfa->seq_tail = tfa->tf[tfa->file_tail].seq_tail;
+               }
+               /* Reset this file head/tail (overwrite). */
+               *headp = -1ULL;
+               *tailp = -1ULL;
+               break;
+       default:
+               abort();
        }
-       /* Reset this file head/tail (overwrite). */
-       *headp = -1ULL;
-       *tailp = -1ULL;
 }
 
-void tracefile_array_commit_seq(struct tracefile_array *tfa)
+void tracefile_array_commit_seq(struct tracefile_array *tfa,
+               uint64_t new_seq_head)
 {
        uint64_t *headp, *tailp;
 
        /* Increment overall head. */
-       tfa->seq_head++;
-       /* If we are committing our first index overall, set tail to 0. */
+       tfa->seq_head = new_seq_head;
+       /* If we are committing our first index overall, set tail to head. */
        if (tfa->seq_tail == -1ULL) {
-               tfa->seq_tail = 0;
+               tfa->seq_tail = new_seq_head;
        }
        if (!tfa->count) {
                /* Not in tracefile rotation mode. */
                return;
        }
-       headp = &tfa->tf[tfa->file_head].seq_head;
-       tailp = &tfa->tf[tfa->file_head].seq_tail;
+       headp = &tfa->tf[tfa->file_head_write].seq_head;
+       tailp = &tfa->tf[tfa->file_head_write].seq_tail;
        /* Update head tracefile seq_head. */
        *headp = tfa->seq_head;
        /*
@@ -118,9 +138,9 @@ void tracefile_array_commit_seq(struct tracefile_array *tfa)
        }
 }
 
-uint64_t tracefile_array_get_file_index_head(struct tracefile_array *tfa)
+uint64_t tracefile_array_get_read_file_index_head(struct tracefile_array *tfa)
 {
-       return tfa->file_head;
+       return tfa->file_head_read;
 }
 
 uint64_t tracefile_array_get_seq_head(struct tracefile_array *tfa)