writeback_pages_written is not necessarily available depending on the kernel config...

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>

diff --git a/lttng-analyses-record b/lttng-analyses-record
index f99e5774e58e1ff17b9d3324881c7d92377d3c55..d6d39718f82858f992b4a14f1d7d7d2af0ca9d3d 100755 (executable)
--- a/lttng-analyses-record
+++ b/lttng-analyses-record
@@ -86,8 +86,15 @@ rm /tmp/lttngout
 trap "destroy" SIGINT SIGTERM
 
 lttng enable-channel -k chan1 --subbuf-size=8M >/dev/null
-lttng enable-event -s $SESSION_NAME -k sched_switch,block_rq_complete,block_rq_issue,block_bio_remap,block_bio_backmerge,netif_receive_skb,net_dev_xmit,sched_process_fork,sched_process_exec,lttng_statedump_process_state,lttng_statedump_file_descriptor,lttng_statedump_block_device,writeback_pages_written,mm_vmscan_wakeup_kswapd,mm_page_free,mm_page_alloc,block_dirty_buffer,irq_handler_entry,irq_handler_exit,softirq_entry,softirq_exit,softirq_raise -c chan1 >/dev/null
+
+# events that always work
+lttng enable-event -s $SESSION_NAME -k sched_switch,block_rq_complete,block_rq_issue,block_bio_remap,block_bio_backmerge,netif_receive_skb,net_dev_xmit,sched_process_fork,sched_process_exec,lttng_statedump_process_state,lttng_statedump_file_descriptor,lttng_statedump_block_device,mm_vmscan_wakeup_kswapd,mm_page_free,mm_page_alloc,block_dirty_buffer,irq_handler_entry,irq_handler_exit,softirq_entry,softirq_exit,softirq_raise -c chan1 >/dev/null
 [[ $? != 0 ]] && exit 2
+
+# events that might fail on specific kernels and that are not mandatory
+lttng enable-event -s $SESSION_NAME -k writeback_pages_written -c chan1 >/dev/null 2>&1
+[[ $? != 0 ]] && echo "Warning: Optional event writeback_pages_written could not be enabled, everything will still work"
+
 lttng enable-event -s $SESSION_NAME -k -c chan1 --syscall -a >/dev/null
 [[ $? != 0 ]] && exit 2
 # if you want to add Perf counters, do something like that :