From: Chuck Lever <chuck.lever@xxxxxxxxxx>
Count and record thread starvation. Administrators can take action
by increasing thread count or decreasing workload.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/linux/sunrpc/svc.h | 5 +++-
include/trace/events/sunrpc.h | 49 ++++++++++++++++++++++++++++++++++-------
net/sunrpc/svc.c | 9 +++++++-
net/sunrpc/svc_xprt.c | 21 ++++++++++--------
4 files changed, 64 insertions(+), 20 deletions(-)
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index dc2d90a655e2..fbfe6ea737c8 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -22,7 +22,6 @@
#include <linux/pagevec.h>
/*
- *
* RPC service thread pool.
*
* Pool of threads and temporary sockets. Generally there is only
@@ -42,6 +41,7 @@ struct svc_pool {
struct percpu_counter sp_sockets_queued;
struct percpu_counter sp_threads_woken;
struct percpu_counter sp_threads_timedout;
+ struct percpu_counter sp_threads_starved;
#define SP_TASK_PENDING (0) /* still work to do even if no
* xprt is queued. */
@@ -427,7 +427,8 @@ int svc_register(const struct svc_serv *, struct net *, const int,
void svc_wake_up(struct svc_serv *);
void svc_reserve(struct svc_rqst *rqstp, int space);
-struct svc_rqst *svc_pool_wake_idle_thread(struct svc_pool *pool);
+struct svc_rqst *svc_pool_wake_idle_thread(struct svc_serv *serv,
+ struct svc_pool *pool);
struct svc_pool *svc_pool_for_cpu(struct svc_serv *serv);
char * svc_print_addr(struct svc_rqst *, char *, size_t);
const char * svc_proc_name(const struct svc_rqst *rqstp);
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 69e42ef30979..9813f4560eef 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -1918,21 +1918,21 @@ TRACE_EVENT(svc_xprt_create_err,
TRACE_EVENT(svc_xprt_enqueue,
TP_PROTO(
const struct svc_xprt *xprt,
- const struct svc_rqst *rqst
+ const struct svc_rqst *wakee
),
- TP_ARGS(xprt, rqst),
+ TP_ARGS(xprt, wakee),
TP_STRUCT__entry(
SVC_XPRT_ENDPOINT_FIELDS(xprt)
- __field(int, pid)
+ __field(pid_t, pid)
),
TP_fast_assign(
SVC_XPRT_ENDPOINT_ASSIGNMENTS(xprt);
- __entry->pid = rqst? rqst->rq_task->pid : 0;
+ __entry->pid = wakee->rq_task->pid;
),
TP_printk(SVC_XPRT_ENDPOINT_FORMAT " pid=%d",
@@ -1963,6 +1963,39 @@ TRACE_EVENT(svc_xprt_dequeue,
SVC_XPRT_ENDPOINT_VARARGS, __entry->wakeup)
);
+#define show_svc_pool_flags(x) \
+ __print_flags(x, "|", \
+ { BIT(SP_TASK_PENDING), "TASK_PENDING" }, \
+ { BIT(SP_CONGESTED), "CONGESTED" })
+
+TRACE_EVENT(svc_pool_starved,
+ TP_PROTO(
+ const struct svc_serv *serv,
+ const struct svc_pool *pool
+ ),
+
+ TP_ARGS(serv, pool),
+
+ TP_STRUCT__entry(
+ __string(name, serv->sv_name)
+ __field(int, pool_id)
+ __field(unsigned int, nrthreads)
+ __field(unsigned long, flags)
+ ),
+
+ TP_fast_assign(
+ __assign_str(name, serv->sv_name);
+ __entry->pool_id = pool->sp_id;
+ __entry->nrthreads = pool->sp_nrthreads;
+ __entry->flags = pool->sp_flags;
+ ),
+
+ TP_printk("service=%s pool=%d flags=%s nrthreads=%u",
+ __get_str(name), __entry->pool_id,
+ show_svc_pool_flags(__entry->flags), __entry->nrthreads
+ )
+);
+
DECLARE_EVENT_CLASS(svc_xprt_event,
TP_PROTO(
const struct svc_xprt *xprt
@@ -2033,16 +2066,16 @@ TRACE_EVENT(svc_xprt_accept,
);
TRACE_EVENT(svc_wake_up,
- TP_PROTO(int pid),
+ TP_PROTO(const struct svc_rqst *wakee),
- TP_ARGS(pid),
+ TP_ARGS(wakee),
TP_STRUCT__entry(
- __field(int, pid)
+ __field(pid_t, pid)
),
TP_fast_assign(
- __entry->pid = pid;
+ __entry->pid = wakee->rq_task->pid;
),
TP_printk("pid=%d", __entry->pid)
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index e81ce5f76abd..04151e22ec44 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -516,6 +516,7 @@ __svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
percpu_counter_init(&pool->sp_sockets_queued, 0, GFP_KERNEL);
percpu_counter_init(&pool->sp_threads_woken, 0, GFP_KERNEL);
percpu_counter_init(&pool->sp_threads_timedout, 0, GFP_KERNEL);
+ percpu_counter_init(&pool->sp_threads_starved, 0, GFP_KERNEL);
}
return serv;
@@ -591,6 +592,7 @@ svc_destroy(struct kref *ref)
percpu_counter_destroy(&pool->sp_sockets_queued);
percpu_counter_destroy(&pool->sp_threads_woken);
percpu_counter_destroy(&pool->sp_threads_timedout);
+ percpu_counter_destroy(&pool->sp_threads_starved);
}
kfree(serv->sv_pools);
kfree(serv);
@@ -691,6 +693,7 @@ svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
/**
* svc_pool_wake_idle_thread - wake an idle thread in @pool
+ * @serv: RPC service
* @pool: service thread pool
*
* Returns an idle service thread (now marked BUSY), or NULL
@@ -698,7 +701,8 @@ svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
* thread and marking it BUSY is atomic with respect to other
* calls to svc_pool_wake_idle_thread().
*/
-struct svc_rqst *svc_pool_wake_idle_thread(struct svc_pool *pool)
+struct svc_rqst *svc_pool_wake_idle_thread(struct svc_serv *serv,
+ struct svc_pool *pool)
{
struct svc_rqst *rqstp;
@@ -714,6 +718,9 @@ struct svc_rqst *svc_pool_wake_idle_thread(struct svc_pool *pool)
return rqstp;
}
rcu_read_unlock();
+
+ trace_svc_pool_starved(serv, pool);
+ percpu_counter_inc(&pool->sp_threads_starved);
return NULL;
}
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index f14476d11b67..859eecb7d52c 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -455,7 +455,7 @@ static bool svc_xprt_ready(struct svc_xprt *xprt)
*/
void svc_xprt_enqueue(struct svc_xprt *xprt)
{
- struct svc_rqst *rqstp;
+ struct svc_rqst *rqstp;
struct svc_pool *pool;
if (!svc_xprt_ready(xprt))
@@ -476,9 +476,11 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
spin_unlock_bh(&pool->sp_lock);
- rqstp = svc_pool_wake_idle_thread(pool);
- if (!rqstp)
+ rqstp = svc_pool_wake_idle_thread(xprt->xpt_server, pool);
+ if (!rqstp) {
set_bit(SP_CONGESTED, &pool->sp_flags);
+ return;
+ }
trace_svc_xprt_enqueue(xprt, rqstp);
}
@@ -584,15 +586,15 @@ static void svc_xprt_release(struct svc_rqst *rqstp)
void svc_wake_up(struct svc_serv *serv)
{
struct svc_pool *pool = &serv->sv_pools[0];
- struct svc_rqst *rqstp;
+ struct svc_rqst *rqstp;
- rqstp = svc_pool_wake_idle_thread(pool);
+ rqstp = svc_pool_wake_idle_thread(serv, pool);
if (!rqstp) {
set_bit(SP_TASK_PENDING, &pool->sp_flags);
return;
}
- trace_svc_wake_up(rqstp->rq_task->pid);
+ trace_svc_wake_up(rqstp);
}
EXPORT_SYMBOL_GPL(svc_wake_up);
@@ -1434,16 +1436,17 @@ static int svc_pool_stats_show(struct seq_file *m, void *p)
struct svc_pool *pool = p;
if (p == SEQ_START_TOKEN) {
- seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
+ seq_puts(m, "# pool packets-arrived xprts-enqueued threads-woken threads-timedout starved\n");
return 0;
}
- seq_printf(m, "%u %llu %llu %llu %llu\n",
+ seq_printf(m, "%u %llu %llu %llu %llu %llu\n",
pool->sp_id,
percpu_counter_sum_positive(&pool->sp_sockets_queued),
percpu_counter_sum_positive(&pool->sp_sockets_queued),
percpu_counter_sum_positive(&pool->sp_threads_woken),
- percpu_counter_sum_positive(&pool->sp_threads_timedout));
+ percpu_counter_sum_positive(&pool->sp_threads_timedout),
+ percpu_counter_sum_positive(&pool->sp_threads_starved));
return 0;
}
