Hey Trond
On 01/20/2012 03:12 PM, Trond Myklebust wrote:
> Add declarations to allow tracing of RPC call creation, running, sleeping,
> and destruction.
>
> Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> ---
> include/linux/sunrpc/sched.h | 2 +-
> include/trace/events/sunrpc.h | 124 +++++++++++++++++++++++++++++++++++++++++
> net/sunrpc/sched.c | 12 ++++
> 3 files changed, 137 insertions(+), 1 deletions(-)
> create mode 100644 include/trace/events/sunrpc.h
>
> diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
> index bd337f9..f7b2df5 100644
> --- a/include/linux/sunrpc/sched.h
> +++ b/include/linux/sunrpc/sched.h
> @@ -271,7 +271,7 @@ static inline int rpc_task_has_priority(struct rpc_task *task, unsigned char pri
> }
>
> #ifdef RPC_DEBUG
> -static inline const char * rpc_qname(struct rpc_wait_queue *q)
> +static inline const char * rpc_qname(const struct rpc_wait_queue *q)
> {
> return ((q && q->name) ? q->name : "unknown");
> }
> diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
> new file mode 100644
> index 0000000..51cc949
> --- /dev/null
> +++ b/include/trace/events/sunrpc.h
> @@ -0,0 +1,124 @@
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM sunrpc
> +
> +#if !defined(_TRACE_SUNRPC_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_SUNRPC_H
> +
> +#include <linux/sunrpc/sched.h>
> +#include <linux/sunrpc/clnt.h>
> +#include <linux/tracepoint.h>
> +
> +DECLARE_EVENT_CLASS(rpc_task_running,
> +
> + TP_PROTO(const struct rpc_clnt *clnt, const struct rpc_task *task, const void *action),
> +
> + TP_ARGS(clnt, task, action),
> +
> + TP_STRUCT__entry(
> + __field(const struct rpc_clnt *, clnt)
> + __field(const struct rpc_task *, task)
> + __field(const void *, action)
> + __field(unsigned long, runstate)
> + __field(int, status)
> + __field(unsigned short, flags)
> + ),
> +
> + TP_fast_assign(
> + __entry->clnt = clnt;
> + __entry->task = task;
> + __entry->action = action;
> + __entry->runstate = task->tk_runstate;
> + __entry->status = task->tk_status;
> + __entry->flags = task->tk_flags;
> + ),
> +
> + TP_printk("task:%p@%p flags=%4.4x state=%4.4lx status=%d action=%pf",
> + __entry->task,
> + __entry->clnt,
> + __entry->flags,
> + __entry->runstate,
> + __entry->status,
> + __entry->action
> + )
> +);
> +
> +DEFINE_EVENT(rpc_task_running, rpc_task_begin,
> +
> + TP_PROTO(const struct rpc_clnt *clnt, const struct rpc_task *task, const void *action),
> +
> + TP_ARGS(clnt, task, action)
> +
> +);
> +
> +DEFINE_EVENT(rpc_task_running, rpc_task_run_action,
> +
> + TP_PROTO(const struct rpc_clnt *clnt, const struct rpc_task *task, const void *action),
> +
> + TP_ARGS(clnt, task, action)
> +
> +);
> +
> +DEFINE_EVENT(rpc_task_running, rpc_task_complete,
> +
> + TP_PROTO(const struct rpc_clnt *clnt, const struct rpc_task *task, const void *action),
> +
> + TP_ARGS(clnt, task, action)
> +
> +);
> +
> +DECLARE_EVENT_CLASS(rpc_task_queued,
> +
> + TP_PROTO(const struct rpc_clnt *clnt, const struct rpc_task *task, const struct rpc_wait_queue *q),
> +
> + TP_ARGS(clnt, task, q),
> +
> + TP_STRUCT__entry(
> + __field(const struct rpc_clnt *, clnt)
> + __field(const struct rpc_task *, task)
> + __field(const struct rpc_wait_queue *, queue)
> + __field(unsigned long, timeout)
> + __field(unsigned long, runstate)
> + __field(int, status)
> + __field(unsigned short, flags)
> + ),
> +
> + TP_fast_assign(
> + __entry->clnt = clnt;
> + __entry->task = task;
> + __entry->queue = q;
> + __entry->timeout = task->tk_timeout;
> + __entry->runstate = task->tk_runstate;
> + __entry->status = task->tk_status;
> + __entry->flags = task->tk_flags;
> + ),
> +
> + TP_printk("task:%p@%p flags=%4.4x state=%4.4lx status=%d timeout=%lu queue=%s",
> + __entry->task,
> + __entry->clnt,
> + __entry->flags,
> + __entry->runstate,
> + __entry->status,
> + __entry->timeout,
> + rpc_qname(__entry->queue)
> + )
> +);
It turns out using rpc_qname() is not quite right...
Neil Horman, from our internal review, points out:
"IIRC we do the TP_fast_assign and TP_printk separately
because we don't serialize the printk on the code path that generates it. I.e.
the data that __entry->queue points to may be freed by the time the printk
dereferences it. I think what you need is to declare in the __entry:
__string( qname, rpc_qname(q))
in TP_fast_assign replace the queue assignment with something like
__entry->qname = __assign_str(rpc_qname(q));
And then in the printk:
__get_str(qname);"
Which basically translate into the following (untested):
DECLARE_EVENT_CLASS(rpc_task_queued,
TP_PROTO(const struct rpc_clnt *clnt, const struct rpc_task *task, const struct rpc_wait_queue *q),
TP_ARGS(clnt, task, q),
TP_STRUCT__entry(
__field(const struct rpc_clnt *, clnt)
__field(const struct rpc_task *, task)
__string(qname, rpc_qname(q))
__field(unsigned long, timeout)
__field(unsigned long, runstate)
__field(int, status)
__field(unsigned short, flags)
),
TP_fast_assign(
__entry->clnt = clnt;
__entry->task = task;
__entry->qname = __assign_str(rpc_qname(q));
__entry->timeout = task->tk_timeout;
__entry->runstate = task->tk_runstate;
__entry->status = task->tk_status;
__entry->flags = task->tk_flags;
),
TP_printk("task:%p@%p flags=%4.4x state=%4.4lx status=%d timeout=%lu queue=%s",
__entry->task,
__entry->clnt,
__entry->flags,
__entry->runstate,
__entry->status,
__entry->timeout,
__get_str(__entry->qname)
)
);
There are a number of examples of this in include/trace/events.
steved.
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