From: Jeff Layton <jeff.layton@primarydata.com>
To: trond.myklebust@primarydata.com
Cc: linux-nfs@vger.kernel.org
Subject: Re: [PATCH] sunrpc: add debugfs file for displaying client rpc_task queue
Date: Tue, 28 Oct 2014 14:30:47 -0400 [thread overview]
Message-ID: <20141028143047.5c1fca24@tlielax.poochiereds.net> (raw)
In-Reply-To: <1414520695-1701-1-git-send-email-jlayton@primarydata.com>
On Tue, 28 Oct 2014 14:24:55 -0400
Jeff Layton <jlayton@primarydata.com> 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@primarydata.com>
> ---
> 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@primarydata.com>
> + */
> +
> +#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;
> +}
> +
> +static void *
> +tasks_next(struct seq_file *f, void *v, loff_t *pos)
> + __releases(&clnt->cl_lock)
> + __acquires(&clnt->cl_lock)
> +{
> + loff_t *p = f->private;
> + struct rpc_task *task = v;
> + struct rpc_clnt *clnt = task->tk_client;
> + struct list_head *next = task->tk_task.next;
> + struct sunrpc_net *sn = net_generic(current->nsproxy->net_ns,
> + sunrpc_net_id);
> +
> + ++*p;
> + ++*pos;
> +
> + /* If there's another task on list, return it */
> + if (next != &clnt->cl_tasks)
> + return list_entry(next, struct rpc_task, tk_task);
> +
> + /* We're finished with this client, move on */
> + spin_unlock(&clnt->cl_lock);
> +next_client:
> + next = clnt->cl_clients.next;
> + if (next == &sn->all_clients)
> + return NULL;
> +
> + clnt = list_entry(next, struct rpc_clnt, cl_clients);
> + if (list_empty(&clnt->cl_tasks))
> + goto next_client;
> + spin_lock(&clnt->cl_lock);
> + if (list_empty(&clnt->cl_tasks)) {
> + spin_unlock(&clnt->cl_lock);
> + goto next_client;
> + }
> + return list_first_entry(&clnt->cl_tasks, struct rpc_task, tk_task);
> +}
> +
> +static void
> +tasks_stop(struct seq_file *f, void *v)
> + __releases(&sn->rpc_client_lock)
> + __releases(&clnt->cl_lock)
> +{
> + struct rpc_task *task = v;
> + struct rpc_clnt *clnt;
> + struct sunrpc_net *sn = net_generic(current->nsproxy->net_ns,
> + sunrpc_net_id);
> +
> + if (v) {
> + clnt = task->tk_client;
> + spin_unlock(&clnt->cl_lock);
> + }
Full disclosure here...
sparse complains about this patch:
net/sunrpc/debugfs.c:36:13: warning: context imbalance in 'tasks_start' - different lock contexts for basic block
net/sunrpc/debugfs.c:59:13: warning: context imbalance in 'tasks_next' - different lock contexts for basic block
net/sunrpc/debugfs.c:110:20: warning: context imbalance in 'tasks_stop' - different lock contexts for basic block
The __acquires/__releases annotations don't help in this case since
tasks_start and tasks_next can conditionally return with the cl_lock
held or not.
If tasks_start/_next return a valid object, then the lock will be held.
If it returns NULL then it won't be. There should be no actual lock
imbalances however.
> + spin_unlock(&sn->rpc_client_lock);
> +}
> +
> +static const struct seq_operations tasks_seq_operations = {
> + .start = tasks_start,
> + .next = tasks_next,
> + .stop = tasks_stop,
> + .show = tasks_show,
> +};
> +
> +static int tasks_open(struct inode *inode, struct file *filp)
> +{
> + return seq_open_private(filp, &tasks_seq_operations,
> + sizeof(loff_t));
> +}
> +
> +static const struct file_operations tasks_fops = {
> + .owner = THIS_MODULE,
> + .open = tasks_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = seq_release_private,
> +};
> +
> +void __exit
> +sunrpc_debugfs_exit(void)
> +{
> + debugfs_remove_recursive(topdir);
> +}
> +
> +int __init
> +sunrpc_debugfs_init(void)
> +{
> + topdir = debugfs_create_dir("sunrpc", NULL);
> + if (!topdir)
> + return -ENOMEM;
> +
> + if (!debugfs_create_file("client_tasks", S_IFREG | S_IRUSR, topdir,
> + NULL, &tasks_fops)) {
> + debugfs_remove_recursive(topdir);
> + return -ENOMEM;
> + }
> + return 0;
> +}
> diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c
> index cd30120de9e4..32583adf3477 100644
> --- a/net/sunrpc/sunrpc_syms.c
> +++ b/net/sunrpc/sunrpc_syms.c
> @@ -97,6 +97,11 @@ init_sunrpc(void)
> err = register_rpc_pipefs();
> if (err)
> goto out4;
> +
> + err = sunrpc_debugfs_init();
> + if (err)
> + goto out5;
> +
> #ifdef RPC_DEBUG
> rpc_register_sysctl();
> #endif
> @@ -104,6 +109,8 @@ init_sunrpc(void)
> init_socket_xprt(); /* clnt sock transport */
> return 0;
>
> +out5:
> + unregister_rpc_pipefs();
> out4:
> unregister_pernet_subsys(&sunrpc_net_ops);
> out3:
> @@ -120,6 +127,7 @@ cleanup_sunrpc(void)
> rpcauth_remove_module();
> cleanup_socket_xprt();
> svc_cleanup_xprt_sock();
> + sunrpc_debugfs_exit();
> unregister_rpc_pipefs();
> rpc_destroy_mempool();
> unregister_pernet_subsys(&sunrpc_net_ops);
--
Jeff Layton <jlayton@primarydata.com>
next prev parent reply other threads:[~2014-10-28 18:30 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-28 18:24 [PATCH] sunrpc: add debugfs file for displaying client rpc_task queue Jeff Layton
2014-10-28 18:30 ` Jeff Layton [this message]
2014-11-24 19:20 ` Trond Myklebust
2014-11-24 21:35 ` Jeff Layton
2014-11-25 19:00 ` [PATCH v2 0/4] " Jeff Layton
2014-11-25 19:00 ` [PATCH v2 1/4] lockd: eliminate LOCKD_DEBUG Jeff Layton
2014-11-25 19:00 ` [PATCH v2 2/4] sunrpc: eliminate RPC_DEBUG Jeff Layton
2014-11-25 19:00 ` [PATCH v2 3/4] sunrpc: eliminate RPC_TRACEPOINTS Jeff Layton
2014-11-25 19:01 ` [PATCH v2 4/4] sunrpc: add debugfs file for displaying client rpc_task queue Jeff Layton
2014-11-25 21:00 ` Jeff Layton
2014-11-26 19:44 ` [PATCH v3 0/5] sunrpc: add some debugfs files for dumping task and xprt info Jeff Layton
2014-11-26 19:44 ` [PATCH v3 1/5] lockd: eliminate LOCKD_DEBUG Jeff Layton
2014-11-26 19:44 ` [PATCH v3 2/5] sunrpc: eliminate RPC_DEBUG Jeff Layton
2014-11-26 19:44 ` [PATCH v3 3/5] sunrpc: eliminate RPC_TRACEPOINTS Jeff Layton
2014-11-26 19:44 ` [PATCH v3 4/5] sunrpc: add debugfs file for displaying client rpc_task queue Jeff Layton
2014-11-26 20:13 ` Anna Schumaker
2014-11-26 20:15 ` Anna Schumaker
2014-11-26 20:52 ` Jeff Layton
2014-11-26 19:44 ` [PATCH v3 5/5] sunrpc: add a debugfs rpc_xprt directory with an info file in it Jeff Layton
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