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Subject[PATCH 11/19] tracing/workqueue: turn workfunc_stats::inserted into unsigned int
Date
From: Zhaolei <zhaolei@cn.fujitsu.com>

struct workfunc_stats belongs to per_cpu struct of cpu_workqueue_stats,
which means we only need to serialize its access from one cpu.

And because trace_workqueue_insertion() is already inside a section
protected by the cpu workqueue lock, we can safely convert it into an
unsigned int.

[ Impact: locking cleanup]

Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
kernel/trace/trace_workqueue.c | 13 +++++--------
1 files changed, 5 insertions(+), 8 deletions(-)
diff --git a/kernel/trace/trace_workqueue.c b/kernel/trace/trace_workqueue.c
index 69ae4aa..7a07d17 100644
--- a/kernel/trace/trace_workqueue.c
+++ b/kernel/trace/trace_workqueue.c
@@ -20,12 +20,9 @@ struct workfunc_stats {

/* Addr of worklet's callback function */
work_func_t func;
- /* Can be inserted on different workqueues, need to be atomic */
- atomic_t inserted;
- /*
- * Don't need to be atomic, works are serialized in a single workqueue
- * thread on a single CPU.
- */
+
+ /* Protected by cpu workqueue lock */
+ unsigned int inserted;
unsigned int executed;
};

@@ -80,7 +77,7 @@ int do_worklet_enqueue(struct cpu_workqueue_stats *cws,

list_add_tail(&wfstat->list, &cws->workfunclist);
found:
- atomic_inc(&wfstat->inserted);
+ wfstat->inserted++;

return 0;
}
@@ -331,7 +328,7 @@ static int workqueue_stat_show(struct seq_file *s, void *p)
int lastwf = list_is_last(&wfstat->list, &cws->workfunclist);
seq_printf(s, "%3d %6d %6u %c-%pF\n",
cws->cpu,
- atomic_read(&wfstat->inserted),
+ wfstat->inserted,
wfstat->executed,
lastwf ? '`' : '|',
wfstat->func);
--
1.6.2.3


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