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SUNRPC: Clean up request deferral tracepoints

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- Rename these so they are easy to enable and search for as a set
- Move the tracepoints to get a more accurate sense of control flow
- Tracepoints should not fire on xprt shutdown
- Display memory address in case data structure had been corrupted
- Abandon dprintk in these paths

I haven't ever gotten one of these tracepoints to trigger. I wonder
if we should simply remove them.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever 2020-04-15 09:05:26 -04:00
parent 1eace0d1e9
commit 8954c5c212
2 changed files with 14 additions and 9 deletions
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11
include/trace/events/sunrpc.h
View File

@ -1406,27 +1406,32 @@ DECLARE_EVENT_CLASS(svc_deferred_event,
TP_ARGS(dr),
TP_STRUCT__entry(
__field(const void *, dr)
__field(u32, xid)
__string(addr, dr->xprt->xpt_remotebuf)
),
TP_fast_assign(
__entry->dr = dr;
__entry->xid = be32_to_cpu(*(__be32 *)(dr->args +
(dr->xprt_hlen>>2)));
__assign_str(addr, dr->xprt->xpt_remotebuf);
),
TP_printk("addr=%s xid=0x%08x", __get_str(addr), __entry->xid)
TP_printk("addr=%s dr=%p xid=0x%08x", __get_str(addr), __entry->dr,
__entry->xid)
);
#define DEFINE_SVC_DEFERRED_EVENT(name) \
DEFINE_EVENT(svc_deferred_event, svc_##name##_deferred, \
DEFINE_EVENT(svc_deferred_event, svc_defer_##name, \
TP_PROTO( \
const struct svc_deferred_req *dr \
), \
TP_ARGS(dr))
DEFINE_SVC_DEFERRED_EVENT(drop);
DEFINE_SVC_DEFERRED_EVENT(revisit);
DEFINE_SVC_DEFERRED_EVENT(queue);
DEFINE_SVC_DEFERRED_EVENT(recv);
TRACE_EVENT(svcsock_new_socket,
TP_PROTO(

12
net/sunrpc/svc_xprt.c
View File

@ -1145,16 +1145,15 @@ static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
set_bit(XPT_DEFERRED, &xprt->xpt_flags);
if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
spin_unlock(&xprt->xpt_lock);
dprintk("revisit canceled\n");
trace_svc_defer_drop(dr);
svc_xprt_put(xprt);
trace_svc_drop_deferred(dr);
kfree(dr);
return;
}
dprintk("revisit queued\n");
dr->xprt = NULL;
list_add(&dr->handle.recent, &xprt->xpt_deferred);
spin_unlock(&xprt->xpt_lock);
trace_svc_defer_queue(dr);
svc_xprt_enqueue(xprt);
svc_xprt_put(xprt);
}
@ -1200,22 +1199,24 @@ static struct cache_deferred_req *svc_defer(struct cache_req *req)
memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
dr->argslen << 2);
}
trace_svc_defer(rqstp);
svc_xprt_get(rqstp->rq_xprt);
dr->xprt = rqstp->rq_xprt;
set_bit(RQ_DROPME, &rqstp->rq_flags);
dr->handle.revisit = svc_revisit;
trace_svc_defer(rqstp);
return &dr->handle;
}
/*
* recv data from a deferred request into an active one
*/
static int svc_deferred_recv(struct svc_rqst *rqstp)
static noinline int svc_deferred_recv(struct svc_rqst *rqstp)
{
struct svc_deferred_req *dr = rqstp->rq_deferred;
trace_svc_defer_recv(dr);
/* setup iov_base past transport header */
rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
/* The iov_len does not include the transport header bytes */
@ -1246,7 +1247,6 @@ static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
struct svc_deferred_req,
handle.recent);
list_del_init(&dr->handle.recent);
trace_svc_revisit_deferred(dr);
} else
clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
spin_unlock(&xprt->xpt_lock);