On Tue, 2018-06-26 at 20:13 -0400, Chuck Lever wrote:
> > On Jun 26, 2018, at 7:56 PM, Dave Wysochanski <dwysocha@xxxxxxxxxx> wrote:
> >
> > The existing rpc_print_iostats has a few shortcomings. First, the naming
> > is not consistent with other functions in the kernel that display stats.
> > Second, it is really displaying stats for an rpc_clnt structure as it
> > displays both xprt stats and per-op stats. Third, it does not handle
> > rpc_clnt clones, which is important for the one in-kernel tree caller
> > of this function, the NFS client's nfs_show_stats function.
> >
> > Fix all of the above by renaming the rpc_print_iostats to
> > rpc_clnt_show_stats and looping through any rpc_clnt clones via
> > cl_parent.
> >
> > Once this interface is fixed, this addresses a problem with NFSv4.
> > Before this patch, the /proc/self/mountstats always showed incorrect
> > counts for NFSv4 state related opcodes such as SEQUENCE and RENEW.
> > These counts were always 0 even though many ops would go over the
> > wire. The reason for this is there are multiple rpc_clnt structures
> > allocated for any given NFSv4 mount, and inside nfs_show_stats() we callled
> > into rpc_print_iostats() which only handled one of them, nfs_server->client.
> > Fix these counts by calling sunrpc's new rpc_clnt_show_stats() function,
> > which handles cloned rpc_clnt structs and prints the stats together.
> >
> > Note that one side-effect of the above is that multiple mounts from
> > the same NFS server will show identical counts in the above ops due
> > to the fact the one rpc_clnt (representing the NFSv4 client state)
> > is shared across mounts.
> >
> > Signed-off-by: Dave Wysochanski <dwysocha@xxxxxxxxxx>
> > ---
> > fs/nfs/super.c | 2 +-
> > include/linux/sunrpc/metrics.h | 6 +++---
> > net/sunrpc/stats.c | 17 ++++++++++++-----
> > 3 files changed, 16 insertions(+), 9 deletions(-)
> >
> > diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> > index 5e470e233c83..bdf39fa1bfbc 100644
> > --- a/fs/nfs/super.c
> > +++ b/fs/nfs/super.c
> > @@ -884,7 +884,7 @@ int nfs_show_stats(struct seq_file *m, struct dentry *root)
> > #endif
> > seq_printf(m, "\n");
> >
> > - rpc_print_iostats(m, nfss->client);
> > + rpc_clnt_show_stats(m, nfss->client);
> >
> > return 0;
> > }
> > diff --git a/include/linux/sunrpc/metrics.h b/include/linux/sunrpc/metrics.h
> > index 9baed7b355b2..3daa5b42d871 100644
> > --- a/include/linux/sunrpc/metrics.h
> > +++ b/include/linux/sunrpc/metrics.h
> > @@ -30,7 +30,7 @@
> > #include <linux/ktime.h>
> > #include <linux/spinlock.h>
> >
> > -#define RPC_IOSTATS_VERS "1.0"
> > +#define RPC_IOSTATS_VERS "1.1"
>
> A quick browse does not reveal a format change in /proc/self/mountstats.
> Did I miss it? If there's no change, VERS should stay "1.0".
>
No there is not a format change, so you're right.
Thanks!
>
> > struct rpc_iostats {
> > spinlock_t om_lock;
> > @@ -82,7 +82,7 @@ void rpc_count_iostats(const struct rpc_task *,
> > struct rpc_iostats *);
> > void rpc_count_iostats_metrics(const struct rpc_task *,
> > struct rpc_iostats *);
> > -void rpc_print_iostats(struct seq_file *, struct rpc_clnt *);
> > +void rpc_clnt_show_stats(struct seq_file *, struct rpc_clnt *);
> > void rpc_free_iostats(struct rpc_iostats *);
> >
> > #else /* CONFIG_PROC_FS */
> > @@ -95,7 +95,7 @@ static inline void rpc_count_iostats_metrics(const struct rpc_task *task,
> > {
> > }
> >
> > -static inline void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt) {}
> > +static inline void rpc_clnt_show_stats(struct seq_file *seq, struct rpc_clnt *clnt) {}
> > static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
> >
> > #endif /* CONFIG_PROC_FS */
> > diff --git a/net/sunrpc/stats.c b/net/sunrpc/stats.c
> > index 32adddd7fb78..2c9453465c78 100644
> > --- a/net/sunrpc/stats.c
> > +++ b/net/sunrpc/stats.c
> > @@ -235,13 +235,12 @@ static void _print_rpc_iostats(struct seq_file *seq, struct rpc_iostats *stats,
> > ktime_to_ms(stats->om_execute));
> > }
> >
> > -void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt)
> > +void rpc_clnt_show_stats(struct seq_file *seq, struct rpc_clnt *clnt)
> > {
> > - struct rpc_iostats *stats = clnt->cl_metrics;
> > struct rpc_xprt *xprt;
> > unsigned int op, maxproc = clnt->cl_maxproc;
> >
> > - if (!stats)
> > + if (!clnt->cl_metrics)
> > return;
> >
> > seq_printf(seq, "\tRPC iostats version: %s ", RPC_IOSTATS_VERS);
> > @@ -256,10 +255,18 @@ void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt)
> >
> > seq_printf(seq, "\tper-op statistics\n");
> > for (op = 0; op < maxproc; op++) {
> > - _print_rpc_iostats(seq, &stats[op], op, clnt->cl_procinfo);
> > + struct rpc_iostats stats = { 0 };
> > + struct rpc_clnt *next = clnt;
> > + do {
> > + _add_rpc_iostats(&stats, &next->cl_metrics[op]);
> > + if (next == next->cl_parent)
> > + break;
> > + next = next->cl_parent;
> > + } while (next);
> > + _print_rpc_iostats(seq, &stats, op, clnt->cl_procinfo);
> > }
> > }
> > -EXPORT_SYMBOL_GPL(rpc_print_iostats);
> > +EXPORT_SYMBOL_GPL(rpc_clnt_show_stats);
> >
> > /*
> > * Register/unregister RPC proc files
> > --
> > 2.14.3
> >
> > --
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>
> --
> Chuck Lever
>
>
>
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