nilfs2: add a tracepoint for transaction events
This patch adds a tracepoint for transaction events of nilfs. With the
tracepoint, these events can be tracked: begin, abort, commit, trylock,
lock, and unlock. Basically, these events have corresponding functions
e.g. begin event corresponds nilfs_transaction_begin(). The unlock event
is an exception. It corresponds to the iteration in
nilfs_transaction_lock().
Only one tracepoint is introcued: nilfs2_transaction_transition. The
above events are distinguished with newly introduced enum. With this
tracepoint, we can analyse a critical section of segment constructoin.
Sample output by tpoint of perf-tools:
cp-4457 [000] ...1 63.266220: nilfs2_transaction_transition: sb = ffff8802112b8800 ti = ffff8800bf5ccc58 count = 1 flags = 9 state = BEGIN
cp-4457 [000] ...1 63.266221: nilfs2_transaction_transition: sb = ffff8802112b8800 ti = ffff8800bf5ccc58 count = 0 flags = 9 state = COMMIT
cp-4457 [000] ...1 63.266221: nilfs2_transaction_transition: sb = ffff8802112b8800 ti = ffff8800bf5ccc58 count = 0 flags = 9 state = COMMIT
segctord-4371 [001] ...1 68.261196: nilfs2_transaction_transition: sb = ffff8802112b8800 ti = ffff8800b889bdf8 count = 0 flags = 10 state = TRYLOCK
segctord-4371 [001] ...1 68.261280: nilfs2_transaction_transition: sb = ffff8802112b8800 ti = ffff8800b889bdf8 count = 0 flags = 10 state = LOCK
segctord-4371 [001] ...1 68.261877: nilfs2_transaction_transition: sb = ffff8802112b8800 ti = ffff8800b889bdf8 count = 1 flags = 10 state = BEGIN
segctord-4371 [001] ...1 68.262116: nilfs2_transaction_transition: sb = ffff8802112b8800 ti = ffff8800b889bdf8 count = 0 flags = 18 state = COMMIT
segctord-4371 [001] ...1 68.265032: nilfs2_transaction_transition: sb = ffff8802112b8800 ti = ffff8800b889bdf8 count = 0 flags = 18 state = UNLOCK
segctord-4371 [001] ...1 132.376847: nilfs2_transaction_transition: sb = ffff8802112b8800 ti = ffff8800b889bdf8 count = 0 flags = 10 state = TRYLOCK
This patch also does trivial cleaning of comma usage in collection stage
transition event for consistent coding style.
Signed-off-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index ef35404..3fc4732 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -214,11 +214,18 @@
{
struct the_nilfs *nilfs;
int ret = nilfs_prepare_segment_lock(ti);
+ struct nilfs_transaction_info *trace_ti;
if (unlikely(ret < 0))
return ret;
- if (ret > 0)
+ if (ret > 0) {
+ trace_ti = current->journal_info;
+
+ trace_nilfs2_transaction_transition(sb, trace_ti,
+ trace_ti->ti_count, trace_ti->ti_flags,
+ TRACE_NILFS2_TRANSACTION_BEGIN);
return 0;
+ }
sb_start_intwrite(sb);
@@ -229,6 +236,11 @@
ret = -ENOSPC;
goto failed;
}
+
+ trace_ti = current->journal_info;
+ trace_nilfs2_transaction_transition(sb, trace_ti, trace_ti->ti_count,
+ trace_ti->ti_flags,
+ TRACE_NILFS2_TRANSACTION_BEGIN);
return 0;
failed:
@@ -261,6 +273,8 @@
ti->ti_flags |= NILFS_TI_COMMIT;
if (ti->ti_count > 0) {
ti->ti_count--;
+ trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+ ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
return 0;
}
if (nilfs->ns_writer) {
@@ -272,6 +286,9 @@
nilfs_segctor_do_flush(sci, 0);
}
up_read(&nilfs->ns_segctor_sem);
+ trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+ ti->ti_flags, TRACE_NILFS2_TRANSACTION_COMMIT);
+
current->journal_info = ti->ti_save;
if (ti->ti_flags & NILFS_TI_SYNC)
@@ -290,10 +307,15 @@
BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
if (ti->ti_count > 0) {
ti->ti_count--;
+ trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+ ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
return;
}
up_read(&nilfs->ns_segctor_sem);
+ trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+ ti->ti_flags, TRACE_NILFS2_TRANSACTION_ABORT);
+
current->journal_info = ti->ti_save;
if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
kmem_cache_free(nilfs_transaction_cachep, ti);
@@ -339,6 +361,9 @@
current->journal_info = ti;
for (;;) {
+ trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+ ti->ti_flags, TRACE_NILFS2_TRANSACTION_TRYLOCK);
+
down_write(&nilfs->ns_segctor_sem);
if (!test_bit(NILFS_SC_PRIOR_FLUSH, &sci->sc_flags))
break;
@@ -350,6 +375,9 @@
}
if (gcflag)
ti->ti_flags |= NILFS_TI_GC;
+
+ trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+ ti->ti_flags, TRACE_NILFS2_TRANSACTION_LOCK);
}
static void nilfs_transaction_unlock(struct super_block *sb)
@@ -362,6 +390,9 @@
up_write(&nilfs->ns_segctor_sem);
current->journal_info = ti->ti_save;
+
+ trace_nilfs2_transaction_transition(sb, ti, ti->ti_count,
+ ti->ti_flags, TRACE_NILFS2_TRANSACTION_UNLOCK);
}
static void *nilfs_segctor_map_segsum_entry(struct nilfs_sc_info *sci,