+/*
+ * Return a struct io_logs, which is added to the tail of the log
+ * list for 'iolog'.
+ */
+static struct io_logs *get_new_log(struct io_log *iolog)
+{
+ size_t new_size, new_samples;
+ struct io_logs *cur_log;
+
+ /*
+ * Cap the size at MAX_LOG_ENTRIES, so we don't keep doubling
+ * forever
+ */
+ if (!iolog->cur_log_max)
+ new_samples = DEF_LOG_ENTRIES;
+ else {
+ new_samples = iolog->cur_log_max * 2;
+ if (new_samples > MAX_LOG_ENTRIES)
+ new_samples = MAX_LOG_ENTRIES;
+ }
+
+ /*
+ * If the alloc size is sufficiently large, quiesce pending IO before
+ * attempting it. This is to avoid spending a long time in alloc with
+ * IO pending, which will unfairly skew the completion latencies of
+ * inflight IO.
+ */
+ new_size = new_samples * log_entry_sz(iolog);
+ if (new_size >= LOG_QUIESCE_SZ)
+ io_u_quiesce(iolog->td);
+
+ cur_log = malloc(sizeof(*cur_log));
+ if (cur_log) {
+ INIT_FLIST_HEAD(&cur_log->list);
+ cur_log->log = malloc(new_size);
+ if (cur_log->log) {
+ cur_log->nr_samples = 0;
+ cur_log->max_samples = new_samples;
+ flist_add_tail(&cur_log->list, &iolog->io_logs);
+ iolog->cur_log_max = new_samples;
+ return cur_log;
+ }
+ free(cur_log);
+ }
+
+ return NULL;
+}
+
+static struct io_logs *get_cur_log(struct io_log *iolog)
+{
+ struct io_logs *cur_log;
+
+ cur_log = iolog_cur_log(iolog);
+ if (!cur_log) {
+ cur_log = get_new_log(iolog);
+ if (!cur_log)
+ return NULL;
+ }
+
+ if (cur_log->nr_samples < cur_log->max_samples)
+ return cur_log;
+
+ /*
+ * No room for a new sample. If we're compressing on the fly, flush
+ * out the current chunk
+ */
+ if (iolog->log_gz) {
+ if (iolog_cur_flush(iolog, cur_log)) {
+ log_err("fio: failed flushing iolog! Will stop logging.\n");
+ return NULL;
+ }
+ }
+
+ /*
+ * Get a new log array, and add to our list
+ */
+ cur_log = get_new_log(iolog);
+ if (!cur_log) {
+ log_err("fio: failed extending iolog! Will stop logging.\n");
+ return NULL;
+ }
+
+ return cur_log;
+}
+