On Tue, Oct 28, 2014 at 2:30 PM, Jeff Layton
<jeff.layton@xxxxxxxxxxxxxxx> wrote:
> On Tue, 28 Oct 2014 14:24:55 -0400
> Jeff Layton <jlayton@xxxxxxxxxxxxxxx> wrote:
>
>> It's possible to get a dump of the RPC task queue by writing a value to
>> /proc/sys/sunrpc/rpc_debug. If you write any value to that file, you get
>> a dump of the RPC client task list into the log buffer. This is a rather
>> inconvenient interface however, and makes it hard to get immediate info
>> about the task queue.
>>
>> Add a new file under debugfs that shows similar info. There are some
>> small differences -- we avoid printing raw kernel addresses in favor of
>> symbolic names and the XID is also displayed.
>>
>> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
>> ---
>> include/linux/sunrpc/clnt.h | 1 +
>> include/linux/sunrpc/debug.h | 13 ++++
>> net/sunrpc/Kconfig | 1 +
>> net/sunrpc/Makefile | 1 +
>> net/sunrpc/clnt.c | 3 +-
>> net/sunrpc/debugfs.c | 153 +++++++++++++++++++++++++++++++++++++++++++
>> net/sunrpc/sunrpc_syms.c | 8 +++
>> 7 files changed, 179 insertions(+), 1 deletion(-)
>> create mode 100644 net/sunrpc/debugfs.c
>>
>> diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
>> index 70736b98c721..265d40bd3109 100644
>> --- a/include/linux/sunrpc/clnt.h
>> +++ b/include/linux/sunrpc/clnt.h
>> @@ -176,5 +176,6 @@ size_t rpc_peeraddr(struct rpc_clnt *, struct sockaddr *, size_t);
>> const char *rpc_peeraddr2str(struct rpc_clnt *, enum rpc_display_format_t);
>> int rpc_localaddr(struct rpc_clnt *, struct sockaddr *, size_t);
>>
>> +const char *rpc_proc_name(const struct rpc_task *task);
>> #endif /* __KERNEL__ */
>> #endif /* _LINUX_SUNRPC_CLNT_H */
>> diff --git a/include/linux/sunrpc/debug.h b/include/linux/sunrpc/debug.h
>> index 9385bd74c860..7c1ef9530087 100644
>> --- a/include/linux/sunrpc/debug.h
>> +++ b/include/linux/sunrpc/debug.h
>> @@ -68,6 +68,19 @@ extern unsigned int nlm_debug;
>> #ifdef RPC_DEBUG
>> void rpc_register_sysctl(void);
>> void rpc_unregister_sysctl(void);
>> +int sunrpc_debugfs_init(void);
>> +void sunrpc_debugfs_exit(void);
>> +#else
>> +static inline int
>> +sunrpc_debugfs_init(void)
>> +{
>> + return 0;
>> +}
>> +static inline void
>> +sunrpc_debugfs_exit(void)
>> +{
>> + return;
>> +}
>> #endif
>>
>> #endif /* _LINUX_SUNRPC_DEBUG_H_ */
>> diff --git a/net/sunrpc/Kconfig b/net/sunrpc/Kconfig
>> index 0754d0f466d2..fb78117b896c 100644
>> --- a/net/sunrpc/Kconfig
>> +++ b/net/sunrpc/Kconfig
>> @@ -35,6 +35,7 @@ config RPCSEC_GSS_KRB5
>> config SUNRPC_DEBUG
>> bool "RPC: Enable dprintk debugging"
>> depends on SUNRPC && SYSCTL
>> + select DEBUG_FS
>> help
>> This option enables a sysctl-based debugging interface
>> that is be used by the 'rpcdebug' utility to turn on or off
>> diff --git a/net/sunrpc/Makefile b/net/sunrpc/Makefile
>> index e5a7a1cac8f3..15e6f6c23c5d 100644
>> --- a/net/sunrpc/Makefile
>> +++ b/net/sunrpc/Makefile
>> @@ -14,6 +14,7 @@ sunrpc-y := clnt.o xprt.o socklib.o xprtsock.o sched.o \
>> addr.o rpcb_clnt.o timer.o xdr.o \
>> sunrpc_syms.o cache.o rpc_pipe.o \
>> svc_xprt.o
>> +sunrpc-$(CONFIG_SUNRPC_DEBUG) += debugfs.o
>> sunrpc-$(CONFIG_SUNRPC_BACKCHANNEL) += backchannel_rqst.o bc_svc.o
>> sunrpc-$(CONFIG_PROC_FS) += stats.o
>> sunrpc-$(CONFIG_SYSCTL) += sysctl.o
>> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
>> index 9acd6ce88db7..5b2e2d3d37c1 100644
>> --- a/net/sunrpc/clnt.c
>> +++ b/net/sunrpc/clnt.c
>> @@ -1397,7 +1397,8 @@ rpc_restart_call(struct rpc_task *task)
>> EXPORT_SYMBOL_GPL(rpc_restart_call);
>>
>> #ifdef RPC_DEBUG
>> -static const char *rpc_proc_name(const struct rpc_task *task)
>> +const char
>> +*rpc_proc_name(const struct rpc_task *task)
>> {
>> const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
>>
>> diff --git a/net/sunrpc/debugfs.c b/net/sunrpc/debugfs.c
>> new file mode 100644
>> index 000000000000..48769338172e
>> --- /dev/null
>> +++ b/net/sunrpc/debugfs.c
>> @@ -0,0 +1,153 @@
>> +/**
>> + * debugfs interface for sunrpc
>> + *
>> + * (c) 2014 Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
>> + */
>> +
>> +#include <linux/debugfs.h>
>> +#include <linux/sunrpc/sched.h>
>> +#include <linux/sunrpc/clnt.h>
>> +#include "netns.h"
>> +
>> +static struct dentry *topdir;
>> +
>> +static int
>> +tasks_show(struct seq_file *f, void *v)
>> +{
>> + u32 xid = 0;
>> + struct rpc_task *task = v;
>> + struct rpc_clnt *clnt = task->tk_client;
>> + const char *rpc_waitq = "none";
>> +
>> + if (RPC_IS_QUEUED(task))
>> + rpc_waitq = rpc_qname(task->tk_waitqueue);
>> +
>> + if (task->tk_rqstp)
>> + xid = be32_to_cpu(task->tk_rqstp->rq_xid);
>> +
>> + seq_printf(f, "%5u %04x %6d 0x%x 0x%x %8ld %ps %sv%u %s a:%ps q:%s\n",
>> + task->tk_pid, task->tk_flags, task->tk_status,
>> + clnt->cl_clid, xid, task->tk_timeout, task->tk_ops,
>> + clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
>> + task->tk_action, rpc_waitq);
>> + return 0;
>> +}
>> +
>> +static void *
>> +tasks_start(struct seq_file *f, loff_t *ppos)
>> + __acquires(&sn->rpc_client_lock)
>> + __acquires(&clnt->cl_lock)
>> +{
>> + loff_t *p = f->private, pos = *ppos;
>> + struct rpc_clnt *clnt;
>> + struct rpc_task *task;
>> + struct sunrpc_net *sn = net_generic(current->nsproxy->net_ns,
>> + sunrpc_net_id);
>> +
>> + *p = pos + 1;
>> + spin_lock(&sn->rpc_client_lock);
>> + list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
>> + spin_lock(&clnt->cl_lock);
>> + list_for_each_entry(task, &clnt->cl_tasks, tk_task)
>> + if (pos-- == 0)
>> + return task;
>> + spin_unlock(&clnt->cl_lock);
>> + }
>> + return NULL;
>> +}
Instead of having a single pseudofile that iterates through all
rpc_clients and all rpc_tasks, should we perhaps have a hierarchy of
subdirectories?
I'm thinking we might want a directory per rpc_client, each containing
a pseudo-file that iterates through all rpc_tasks for that rpc_client
only. The reason for doing so would be so that we can add pseudofiles
to display more per-rpc_client debugging info, such as cl_nodename,
cl_program->name, cl_prog, cl_vers. Maybe also with a symlink to
another subdirectory that displays per-xprt debugging information?
i.e. a hierarchy of the form
debugfs/
rpc_clients/
1/
cl_tasks
cl_xprt->../../rpc_xprt/1
.....
2/
cl_tasks
cl_xprt->../../rpc_xprt/1
.....
rpc_xprt/
1/
servername
.....
--
Trond Myklebust
Linux NFS client maintainer, PrimaryData
trond.myklebust@xxxxxxxxxxxxxxx
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