The per-op stats displayed in /self/proc/mountstats are collected in the sunrpc
layer and are collected per rpc_client. This has worked for nfs thus far
since only one nfs_client was ever associated with a mountpoint, but with
NFS4.1+PNFS+filelayout an nfs mount can have more than one nfs_client.
This can be seen with a pnfs mount where no data server is the same as the MDS -
all reads, writes and commits will never make it into the current mountstats
output.
I took the approach of keeping the stats from the MDS and DSs separate in the
/proc/self/mountstats output to avoid doing too much in the kernel, and to
expose the fact that these stats are from separate connections (maybe for later
use).
This method has issues:
1) even changing the "statvers" of mountstats doesn't stop the userland
mountstats(8) from trying to parse this output -- and it does so
incorrectly.
2) when using DS multipath this method fails to count operations that happened
on a different path to the same DS (after a failure).
3) currently this will display stats twice when DS == MDS.
So... What should I do here?
A different approach is to add support in net/sunrpc to specify a "parent"
stat structure so that operations on DS nfs_clients bump stats on
the main nfs_server->nfs_client->rpc_client. This would take care of all the
issues with the current patch, but seems like a hack.
One task that seems like a good thing to do is to fix mountstats(8) to respect
the "statsvers" value.
Thoughts?
---
I cleaned up this patch, but I still have reservations (noted in commit message)
fs/nfs/nfs4filelayout.c | 23 +++++++++++++++++++++++
fs/nfs/pnfs.h | 20 ++++++++++++++++++++
fs/nfs/pnfs_dev.c | 25 +++++++++++++++++++++++++
fs/nfs/super.c | 1 +
include/linux/nfs_iostat.h | 2 +-
5 files changed, 70 insertions(+), 1 deletions(-)
diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index 79be7ac..9410fd0 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -33,6 +33,8 @@
#include <linux/nfs_page.h>
#include <linux/module.h>
+#include <linux/sunrpc/metrics.h>
+
#include "internal.h"
#include "nfs4filelayout.h"
@@ -918,6 +920,26 @@ filelayout_free_deveiceid_node(struct nfs4_deviceid_node *d)
nfs4_fl_free_deviceid(container_of(d, struct nfs4_file_layout_dsaddr, id_node));
}
+static void
+filelayout_rpc_print_iostats(struct seq_file *m, struct nfs4_deviceid_node *d)
+{
+ struct nfs4_file_layout_dsaddr *dsaddr;
+ struct nfs4_pnfs_ds *ds;
+ u32 i;
+
+ dsaddr = container_of(d, struct nfs4_file_layout_dsaddr, id_node);
+
+ for (i = 0; i < dsaddr->ds_num; i++) {
+ ds = dsaddr->ds_list[i];
+
+ if (ds && ds->ds_clp) {
+ seq_printf(m, " pnfs dataserver %s\n",
+ ds->ds_remotestr);
+ rpc_print_iostats(m, ds->ds_clp->cl_rpcclient);
+ }
+ }
+}
+
static struct pnfs_layoutdriver_type filelayout_type = {
.id = LAYOUT_NFSV4_1_FILES,
.name = "LAYOUT_NFSV4_1_FILES",
@@ -932,6 +954,7 @@ static struct pnfs_layoutdriver_type filelayout_type = {
.read_pagelist = filelayout_read_pagelist,
.write_pagelist = filelayout_write_pagelist,
.free_deviceid_node = filelayout_free_deveiceid_node,
+ .ds_rpc_print_iostats = filelayout_rpc_print_iostats,
};
static int __init nfs4filelayout_init(void)
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 53d593a..0a5e020 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -119,6 +119,9 @@ struct pnfs_layoutdriver_type {
void (*encode_layoutcommit) (struct pnfs_layout_hdr *layoutid,
struct xdr_stream *xdr,
const struct nfs4_layoutcommit_args *args);
+
+ void (*ds_rpc_print_iostats) (struct seq_file *,
+ struct nfs4_deviceid_node *);
};
struct pnfs_layout_hdr {
@@ -239,6 +242,10 @@ void nfs4_init_deviceid_node(struct nfs4_deviceid_node *,
struct nfs4_deviceid_node *nfs4_insert_deviceid_node(struct nfs4_deviceid_node *);
bool nfs4_put_deviceid_node(struct nfs4_deviceid_node *);
void nfs4_deviceid_purge_client(const struct nfs_client *);
+void nfs4_deviceid_rpc_print_iostats(struct seq_file *seq,
+ const struct nfs_client *clp,
+ const struct pnfs_layoutdriver_type *ld);
+
static inline int lo_fail_bit(u32 iomode)
{
@@ -328,6 +335,14 @@ static inline int pnfs_return_layout(struct inode *ino)
return 0;
}
+static inline void
+pnfs_rpc_print_iostats(struct seq_file *m, struct nfs_server *nfss)
+{
+ if (!pnfs_enabled_sb(nfss))
+ return;
+ nfs4_deviceid_rpc_print_iostats(m, nfss->nfs_client,
+ nfss->pnfs_curr_ld);
+}
#else /* CONFIG_NFS_V4_1 */
static inline void pnfs_destroy_all_layouts(struct nfs_client *clp)
@@ -429,6 +444,11 @@ static inline int pnfs_layoutcommit_inode(struct inode *inode, bool sync)
static inline void nfs4_deviceid_purge_client(struct nfs_client *ncl)
{
}
+
+static inline void
+pnfs_rpc_print_iostats(struct seq_file *m, struct nfs_server *nfss)
+{
+}
#endif /* CONFIG_NFS_V4_1 */
#endif /* FS_NFS_PNFS_H */
diff --git a/fs/nfs/pnfs_dev.c b/fs/nfs/pnfs_dev.c
index 4f359d2..277de87 100644
--- a/fs/nfs/pnfs_dev.c
+++ b/fs/nfs/pnfs_dev.c
@@ -115,6 +115,31 @@ nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld,
}
EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);
+
+void
+nfs4_deviceid_rpc_print_iostats(struct seq_file *seq,
+ const struct nfs_client *clp,
+ const struct pnfs_layoutdriver_type *ld)
+{
+ struct nfs4_deviceid_node *d;
+ struct hlist_node *n;
+ long h;
+
+ if (!ld->ds_rpc_print_iostats)
+ return;
+
+ rcu_read_lock();
+ for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++) {
+ hlist_for_each_entry_rcu(d, n, &nfs4_deviceid_cache[h], node)
+ if (d->ld == ld && d->nfs_client == clp) {
+ if (atomic_read(&d->ref))
+ ld->ds_rpc_print_iostats(seq, d);
+ }
+ }
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(nfs4_deviceid_rpc_print_iostats);
+
/*
* Remove a deviceid from cache
*
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index d18a90b..453e496 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -871,6 +871,7 @@ static int nfs_show_stats(struct seq_file *m, struct dentry *root)
seq_printf(m, "\n");
rpc_print_iostats(m, nfss->client);
+ pnfs_rpc_print_iostats(m, nfss);
return 0;
}
diff --git a/include/linux/nfs_iostat.h b/include/linux/nfs_iostat.h
index 8866bb3..7fe4605 100644
--- a/include/linux/nfs_iostat.h
+++ b/include/linux/nfs_iostat.h
@@ -21,7 +21,7 @@
#ifndef _LINUX_NFS_IOSTAT
#define _LINUX_NFS_IOSTAT
-#define NFS_IOSTAT_VERS "1.0"
+#define NFS_IOSTAT_VERS "2.0"
/*
* NFS byte counters
--
1.7.4.4
--
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