Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-ey0-f174.google.com ([209.85.215.174]:65401 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750968Ab2BMIF3 (ORCPT ); Mon, 13 Feb 2012 03:05:29 -0500 Received: by eaah12 with SMTP id h12so1695299eaa.19 for ; Mon, 13 Feb 2012 00:05:27 -0800 (PST) Message-ID: <4F38C443.2060307@tonian.com> Date: Mon, 13 Feb 2012 10:05:23 +0200 From: Benny Halevy MIME-Version: 1.0 To: "Adamson, Dros" CC: Chuck Lever , "Myklebust, Trond" , linux-nfs Subject: Re: [PATCH] RFC: NFS - filelayout DS rpc mountstats support References: <1328721042-9335-1-git-send-email-dros@netapp.com> <1CFC0549-DFAC-4530-A3A5-876DDAE8C5DE@oracle.com> In-Reply-To: Content-Type: text/plain; charset=windows-1252 Sender: linux-nfs-owner@vger.kernel.org List-ID: Sorry for the late response. On 2012-02-08 23:04, Adamson, Dros wrote: > > On Feb 8, 2012, at 12:26 PM, Chuck Lever wrote: > >> Hi- >> >> On Feb 8, 2012, at 12:10 PM, Weston Andros Adamson wrote: >> >>> The per-op stats displayed in /self/proc/mountstats are collected in the sunrpc >> >> You mean /proc/self/mountstats here. > > oops! > >> >>> 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. >> >> User land is broken then. :-) > > Agreed! > >> >>> 2) when using DS multipath this method fails to count operations that happened >>> on a different path to the same DS (after a failure). > > I should have noted that this isn't a problem yet because I haven't submitted the multipath failover patches :) > >>> >>> 3) currently this will display stats twice when DS == MDS. >> >> Why is this case hard to detect in the kernel or in mountstats? > > Not hard, just an issue with the current patch. > >> >>> >>> 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. >> >> Is this the same as displaying all data in one set of stats? > > Yes > >> >> Seems like that might be the best next step, then we can split up the MDS and DS stats at some later point. Splitting up the MDS/DS stats is important to tell when DS I/O is being done and how effective it is. Benny > > Ok, I'll try to do that. > > Any advice on how to handle the "xprt: ?" line? Obviously the different underlying rpc_clients will have different values. I'd have to look at mountstats(8) some more, but I *think* we could just make it a comma separated list. > > For the 'next step', we can use this patch - we just need to figure out where it should go. Do we keep it in /proc/self/mountstats? I think because of problem #2 we might want to move them out to somewhere in /proc/fs/nfsfs/ along with other per-DS statistics. > >> >>> One task that seems like a good thing to do is to fix mountstats(8) to respect >>> the "statsvers" value. >> >> Agree. > > I'll do this first. > > Thanks Chuck! > > -dros > >> >>> >>> 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 >>> #include >>> >>> +#include >>> + >>> #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 >>> >> >> -- >> Chuck Lever >> chuck[dot]lever[at]oracle[dot]com >> >> >> >> >