Add informational messages during blktrace setup when version 1 tools
are used on kernels with CONFIG_BLK_DEV_ZONED enabled. This alerts users
that REQ_OP_ZONE_* events will be dropped and suggests upgrading to
blktrace tools version 2 or later.
The warning is printed once during trace setup to inform users about
the limitation without spamming the logs during tracing operations.
Version 2 blktrace tools properly handle zone management operations
(zone reset, zone open, zone close, zone finish, zone append) that
were added for zoned block devices.
Example output:
blktests (master) # ./check blktrace
blktrace/001 (blktrace zone management command tracing) [passed]
runtime 3.882s ... 3.866s
blktests (master) # dmesg -c
[ 95.874361] blktrace: nullb0:blktrace events for REQ_OP_ZONE_XXX will be
dropped
[ 95.874372] blktrace: use blktrace tools version >= 2 to track
REQ_OP_ZONE_XXX
blktests (master) #
This helps users understand why zone operation traces may be missing
when using older blktrace tool versions with modern kernels that
support REQ_OP_ZONE_XXX in blktrace.
Signed-off-by: Chaitanya Kulkarni <[email protected]>
---
kernel/trace/blktrace.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 776ae4190f36..200d0deb6c90 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -690,6 +690,12 @@ static void blk_trace_setup_finalize(struct request_queue
*q,
*/
strreplace(buts->name, '/', '_');
+ if (version == 1 && (IS_ENABLED(CONFIG_BLK_DEV_ZONED))) {
+ pr_info("%s:blktrace events for REQ_OP_ZONE_XXX will be
dropped\n",
+ name);
+ pr_info("use blktrace tools version >= 2 to track
REQ_OP_ZONE_XXX\n");
+ }
+
bt->version = version;
bt->act_mask = buts->act_mask;
if (!bt->act_mask)
--
2.40.0
