From 83a712e0afefaf68555f816ea78ecd2862c6cf30 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Fri, 21 Nov 2014 14:19:31 -0500 Subject: [PATCH] sunrpc: add some tracepoints around enqueue and dequeue of svc_xprt These were useful when I was tracking down a race condition between svc_xprt_do_enqueue and svc_get_next_xprt. Signed-off-by: Jeff Layton Signed-off-by: J. Bruce Fields --- include/trace/events/sunrpc.h | 94 +++++++++++++++++++++++++++++++++++ net/sunrpc/svc_xprt.c | 22 +++++--- 2 files changed, 109 insertions(+), 7 deletions(-) diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h index ee4438a63a48..b9c1dc6c825a 100644 --- a/include/trace/events/sunrpc.h +++ b/include/trace/events/sunrpc.h @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -480,6 +481,99 @@ DEFINE_EVENT(svc_rqst_status, svc_send, TP_PROTO(struct svc_rqst *rqst, int status), TP_ARGS(rqst, status)); +#define show_svc_xprt_flags(flags) \ + __print_flags(flags, "|", \ + { (1UL << XPT_BUSY), "XPT_BUSY"}, \ + { (1UL << XPT_CONN), "XPT_CONN"}, \ + { (1UL << XPT_CLOSE), "XPT_CLOSE"}, \ + { (1UL << XPT_DATA), "XPT_DATA"}, \ + { (1UL << XPT_TEMP), "XPT_TEMP"}, \ + { (1UL << XPT_DEAD), "XPT_DEAD"}, \ + { (1UL << XPT_CHNGBUF), "XPT_CHNGBUF"}, \ + { (1UL << XPT_DEFERRED), "XPT_DEFERRED"}, \ + { (1UL << XPT_OLD), "XPT_OLD"}, \ + { (1UL << XPT_LISTENER), "XPT_LISTENER"}, \ + { (1UL << XPT_CACHE_AUTH), "XPT_CACHE_AUTH"}, \ + { (1UL << XPT_LOCAL), "XPT_LOCAL"}) + +TRACE_EVENT(svc_xprt_do_enqueue, + TP_PROTO(struct svc_xprt *xprt, struct svc_rqst *rqst), + + TP_ARGS(xprt, rqst), + + TP_STRUCT__entry( + __field(struct svc_xprt *, xprt) + __field(struct svc_rqst *, rqst) + ), + + TP_fast_assign( + __entry->xprt = xprt; + __entry->rqst = rqst; + ), + + TP_printk("xprt=0x%p addr=%pIScp pid=%d flags=%s", __entry->xprt, + (struct sockaddr *)&__entry->xprt->xpt_remote, + __entry->rqst ? __entry->rqst->rq_task->pid : 0, + show_svc_xprt_flags(__entry->xprt->xpt_flags)) +); + +TRACE_EVENT(svc_xprt_dequeue, + TP_PROTO(struct svc_xprt *xprt), + + TP_ARGS(xprt), + + TP_STRUCT__entry( + __field(struct svc_xprt *, xprt) + __field_struct(struct sockaddr_storage, ss) + __field(unsigned long, flags) + ), + + TP_fast_assign( + __entry->xprt = xprt, + xprt ? memcpy(&__entry->ss, &xprt->xpt_remote, sizeof(__entry->ss)) : memset(&__entry->ss, 0, sizeof(__entry->ss)); + __entry->flags = xprt ? xprt->xpt_flags : 0; + ), + + TP_printk("xprt=0x%p addr=%pIScp flags=%s", __entry->xprt, + (struct sockaddr *)&__entry->ss, + show_svc_xprt_flags(__entry->flags)) +); + +TRACE_EVENT(svc_wake_up, + TP_PROTO(int pid), + + TP_ARGS(pid), + + TP_STRUCT__entry( + __field(int, pid) + ), + + TP_fast_assign( + __entry->pid = pid; + ), + + TP_printk("pid=%d", __entry->pid) +); + +TRACE_EVENT(svc_handle_xprt, + TP_PROTO(struct svc_xprt *xprt, int len), + + TP_ARGS(xprt, len), + + TP_STRUCT__entry( + __field(struct svc_xprt *, xprt) + __field(int, len) + ), + + TP_fast_assign( + __entry->xprt = xprt; + __entry->len = len; + ), + + TP_printk("xprt=0x%p addr=%pIScp len=%d flags=%s", __entry->xprt, + (struct sockaddr *)&__entry->xprt->xpt_remote, __entry->len, + show_svc_xprt_flags(__entry->xprt->xpt_flags)) +); #endif /* _TRACE_SUNRPC_H */ #include diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index ed90d955f733..73d40bd1839a 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -322,12 +322,12 @@ static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt) static void svc_xprt_do_enqueue(struct svc_xprt *xprt) { struct svc_pool *pool; - struct svc_rqst *rqstp; + struct svc_rqst *rqstp = NULL; int cpu; bool queued = false; if (!svc_xprt_has_something_to_do(xprt)) - return; + goto out; /* Mark transport as busy. It will remain in this state until * the provider calls svc_xprt_received. We update XPT_BUSY @@ -337,7 +337,7 @@ static void svc_xprt_do_enqueue(struct svc_xprt *xprt) if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) { /* Don't enqueue transport while already enqueued */ dprintk("svc: transport %p busy, not enqueued\n", xprt); - return; + goto out; } cpu = get_cpu(); @@ -377,7 +377,7 @@ redo_search: atomic_long_inc(&pool->sp_stats.threads_woken); wake_up_process(rqstp->rq_task); put_cpu(); - return; + goto out; } rcu_read_unlock(); @@ -396,7 +396,10 @@ redo_search: spin_unlock_bh(&pool->sp_lock); goto redo_search; } + rqstp = NULL; put_cpu(); +out: + trace_svc_xprt_do_enqueue(xprt, rqstp); } /* @@ -420,7 +423,7 @@ static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool) struct svc_xprt *xprt = NULL; if (list_empty(&pool->sp_sockets)) - return NULL; + goto out; spin_lock_bh(&pool->sp_lock); if (likely(!list_empty(&pool->sp_sockets))) { @@ -433,7 +436,8 @@ static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool) xprt, atomic_read(&xprt->xpt_ref.refcount)); } spin_unlock_bh(&pool->sp_lock); - +out: + trace_svc_xprt_dequeue(xprt); return xprt; } @@ -515,6 +519,7 @@ void svc_wake_up(struct svc_serv *serv) rcu_read_unlock(); dprintk("svc: daemon %p woken up.\n", rqstp); wake_up_process(rqstp->rq_task); + trace_svc_wake_up(rqstp->rq_task->pid); return; } rcu_read_unlock(); @@ -522,6 +527,7 @@ void svc_wake_up(struct svc_serv *serv) /* No free entries available */ set_bit(SP_TASK_PENDING, &pool->sp_flags); smp_wmb(); + trace_svc_wake_up(0); } EXPORT_SYMBOL_GPL(svc_wake_up); @@ -740,7 +746,7 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt) dprintk("svc_recv: found XPT_CLOSE\n"); svc_delete_xprt(xprt); /* Leave XPT_BUSY set on the dead xprt: */ - return 0; + goto out; } if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) { struct svc_xprt *newxpt; @@ -771,6 +777,8 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt) } /* clear XPT_BUSY: */ svc_xprt_received(xprt); +out: + trace_svc_handle_xprt(xprt, len); return len; }