Filesystems like XFS can implement atomic write I/O using either REQ_ATOMIC
flag set in the bio or via CoW operation. It will be useful if we have a
flag in trace events to distinguish between the two. This patch adds
char 'a' to rwbs field of the trace events if REQ_ATOMIC flag is set in
the bio.
<W/ REQ_ATOMIC>
=================
xfs_io-1107 [002] ..... 406.206441: block_rq_issue: 8,48 WSa 16384 () 768 + 32 none,0,0 [xfs_io]
<idle>-0 [002] ..s1. 406.209918: block_rq_complete: 8,48 WSa () 768 + 32 none,0,0 [0]
<W/O REQ_ATOMIC>
===============
xfs_io-1108 [002] ..... 411.212317: block_rq_issue: 8,48 WS 16384 () 1024 + 32 none,0,0 [xfs_io]
<idle>-0 [002] ..s1. 411.215842: block_rq_complete: 8,48 WS () 1024 + 32 none,0,0 [0]
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
---
include/trace/events/block.h | 2 +-
kernel/trace/blktrace.c | 2 ++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index bd0ea07338eb..de538b110ea1 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -11,7 +11,7 @@
#include <linux/tracepoint.h>
#include <uapi/linux/ioprio.h>
-#define RWBS_LEN 8
+#define RWBS_LEN 9
#define IOPRIO_CLASS_STRINGS \
{ IOPRIO_CLASS_NONE, "none" }, \
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 3679a6d18934..6badf296ab2b 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1896,6 +1896,8 @@ void blk_fill_rwbs(char *rwbs, blk_opf_t opf)
rwbs[i++] = 'S';
if (opf & REQ_META)
rwbs[i++] = 'M';
+ if (opf & REQ_ATOMIC)
+ rwbs[i++] = 'a';
rwbs[i] = '\0';
}
--
2.48.1
