From: "J. Bruce Fields" Subject: Re: [patch 03/29] knfsd: add userspace controls for stats tables Date: Sat, 25 Apr 2009 17:57:45 -0400 Message-ID: <20090425215745.GA5088@fieldses.org> References: <20090331202800.739621000@sgi.com> <20090331202938.939647000@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linux NFS ML To: Greg Banks Return-path: Received: from mail.fieldses.org ([141.211.133.115]:37059 "EHLO pickle.fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752150AbZDYV5p (ORCPT ); Sat, 25 Apr 2009 17:57:45 -0400 In-Reply-To: <20090331202938.939647000@sgi.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, Apr 01, 2009 at 07:28:03AM +1100, Greg Banks wrote: > Add two control files to /proc/fs/nfsd: > > * "stats_enabled" can be used to disable or enable the gathering > of per-client and per-export statistics in the server. > > * "stats_prune_period" can be used to set the period at > which the pruning timer runs, in seconds. Unused stats > entries will survive at most twice that time. > > Signed-off-by: Greg Banks > --- > > fs/nfsd/nfsctl.c | 99 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 99 insertions(+) > > Index: bfields/fs/nfsd/nfsctl.c > =================================================================== > --- bfields.orig/fs/nfsd/nfsctl.c > +++ bfields/fs/nfsd/nfsctl.c > @@ -64,6 +64,8 @@ enum { > NFSD_Versions, > NFSD_Ports, > NFSD_MaxBlkSize, > + NFSD_Stats_Enabled, > + NFSD_Stats_Prune_Period, > /* > * The below MUST come last. Otherwise we leave a hole in nfsd_files[] > * with !CONFIG_NFSD_V4 and simple_fill_super() goes oops > @@ -92,6 +94,8 @@ static ssize_t write_pool_threads(struct > static ssize_t write_versions(struct file *file, char *buf, size_t size); > static ssize_t write_ports(struct file *file, char *buf, size_t size); > static ssize_t write_maxblksize(struct file *file, char *buf, size_t size); > +static ssize_t write_stats_enabled(struct file *file, char *buf, size_t size); > +static ssize_t write_stats_prune_period(struct file *file, char *buf, size_t size); > #ifdef CONFIG_NFSD_V4 > static ssize_t write_leasetime(struct file *file, char *buf, size_t size); > static ssize_t write_recoverydir(struct file *file, char *buf, size_t size); > @@ -113,6 +117,8 @@ static ssize_t (*write_op[])(struct file > [NFSD_Versions] = write_versions, > [NFSD_Ports] = write_ports, > [NFSD_MaxBlkSize] = write_maxblksize, > + [NFSD_Stats_Enabled] = write_stats_enabled, > + [NFSD_Stats_Prune_Period] = write_stats_prune_period, > #ifdef CONFIG_NFSD_V4 > [NFSD_Leasetime] = write_leasetime, > [NFSD_RecoveryDir] = write_recoverydir, > @@ -1121,6 +1127,97 @@ static ssize_t write_maxblksize(struct f > return sprintf(buf, "%d\n", nfsd_max_blksize); > } > > +extern int nfsd_stats_enabled; > + > +/** > + * write_stats_enabled - Set or report whether per-client/ > + * per-export stats are enabled. > + * > + * Input: > + * buf: ignored > + * size: zero > + * > + * OR > + * > + * Input: > + * buf: C string containing an unsigned > + * integer value representing the new value > + * size: non-zero length of C string in @buf > + * Output: > + * On success: passed-in buffer filled with '\n'-terminated C string > + * containing numeric value of the current setting > + * return code is the size in bytes of the string > + * On error: return code is zero or a negative errno value > + */ > +static ssize_t write_stats_enabled(struct file *file, char *buf, size_t size) > +{ > + char *mesg = buf; > + if (size > 0) { > + int enabled; > + int rv = get_int(&mesg, &enabled); > + if (rv) > + return rv; > + /* check `enabled' against allowed range */ > + if (enabled < 0 || enabled > 1) > + return -EINVAL; > + /* > + * We can change the enabled flag at any time without > + * locking. All it controls is whether stats are > + * gathered for new incoming NFS calls. Old gathered > + * stats still sit around in the hash tables until > + * naturally pruned. > + */ > + nfsd_stats_enabled = enabled; > + } > + return sprintf(buf, "%d\n", nfsd_stats_enabled); > +} > + > +extern int nfsd_stats_prune_period; > + > +/** > + * write_stats_prune_period - Set or report the period for pruning > + * old per-client/per-export stats entries, > + * in seconds. > + * > + * Input: > + * buf: ignored > + * size: zero > + * > + * OR > + * > + * Input: > + * buf: C string containing an unsigned > + * integer value representing the new value > + * size: non-zero length of C string in @buf > + * Output: > + * On success: passed-in buffer filled with '\n'-terminated C string > + * containing numeric value of the current setting > + * return code is the size in bytes of the string > + * On error: return code is zero or a negative errno value > + */ Just an idle remark, don't worry about this for now, but: we might want to rein in this write_*() comment format a little some day. A lot of the content seems duplicated. --b. > +static ssize_t write_stats_prune_period(struct file *file, char *buf, size_t size) > +{ > + char *mesg = buf; > + if (size > 0) { > + int period; > + int rv = get_int(&mesg, &period); > + if (rv) > + return rv; > + /* check `period' against allowed range */ > + if (period < 10 || period > 14*86400) > + return -EINVAL; > + /* > + * We can change the period at any time without > + * locking. All it controls is the timeout on the > + * next run of the prune timer. This might cause > + * some unexpected behaviour if the period is > + * changed from really high to really low. > + */ > + nfsd_stats_prune_period = period; > + } > + return sprintf(buf, "%d\n", nfsd_stats_prune_period); > +} > + > #ifdef CONFIG_NFSD_V4 > extern time_t nfs4_leasetime(void); > > @@ -1263,6 +1360,8 @@ static int nfsd_fill_super(struct super_ > [NFSD_Versions] = {"versions", &transaction_ops, S_IWUSR|S_IRUSR}, > [NFSD_Ports] = {"portlist", &transaction_ops, S_IWUSR|S_IRUGO}, > [NFSD_MaxBlkSize] = {"max_block_size", &transaction_ops, S_IWUSR|S_IRUGO}, > + [NFSD_Stats_Enabled] = {"stats_enabled", &transaction_ops, S_IWUSR|S_IRUGO}, > + [NFSD_Stats_Prune_Period] = {"stats_prune_period", &transaction_ops, S_IWUSR|S_IRUGO}, > #ifdef CONFIG_NFSD_V4 > [NFSD_Leasetime] = {"nfsv4leasetime", &transaction_ops, S_IWUSR|S_IRUSR}, > [NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR}, > > -- > Greg