kern/148510: [sysctl][patch] Document some sysctls

[Galimov Albert]

>Number:         148510
>Category:       kern
>Synopsis:       [sysctl][patch] Document some sysctls
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          doc-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Jul 12 03:40:06 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Galimov Albert
>Release:        HEAD
>Organization:
>Environment:
HEAD
>Description:
Some sysctls are not documented
>How-To-Repeat:

>Fix:
Patch to sys/kern/vfs_subr.c

Patch attached with submission follows:

Index: sys/kern/vfs_subr.c
===================================================================
--- sys/kern/vfs_subr.c	(revision 209901)
+++ sys/kern/vfs_subr.c	(working copy)
@@ -121,7 +121,7 @@
  */
 static unsigned long	numvnodes;
 
-SYSCTL_LONG(_vfs, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0, "");
+SYSCTL_LONG(_vfs, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0, "Number of vnodes in existence");
 
 /*
  * Conversion tables for conversion from vnode types to inode formats
@@ -150,7 +150,7 @@
 SYSCTL_LONG(_vfs, OID_AUTO, wantfreevnodes, CTLFLAG_RW, &wantfreevnodes, 0, "");
 /* Number of vnodes in the free list. */
 static u_long freevnodes;
-SYSCTL_LONG(_vfs, OID_AUTO, freevnodes, CTLFLAG_RD, &freevnodes, 0, "");
+SYSCTL_LONG(_vfs, OID_AUTO, freevnodes, CTLFLAG_RD, &freevnodes, 0, "Number of vnodes in the free list");
 
 static int vlru_allow_cache_src;
 SYSCTL_INT(_vfs, OID_AUTO, vlru_allow_cache_src, CTLFLAG_RW,
@@ -162,7 +162,8 @@
  * XXX these are probably of (very) limited utility now.
  */
 static int reassignbufcalls;
-SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls, 0, "");
+SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls, 0, 
+	"Various variables used for debugging the new implementation of reassignbuf()");
 
 /*
  * Cache for the mount type id assigned to NFS.  This is used for
@@ -237,14 +238,14 @@
 static int syncer_maxdelay = SYNCER_MAXDELAY;	/* maximum delay time */
 static int syncdelay = 30;		/* max time to delay syncing data */
 static int filedelay = 30;		/* time to delay syncing files */
-SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0, "");
+SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0, "Time to delay syncing files");
 static int dirdelay = 29;		/* time to delay syncing directories */
-SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0, "");
+SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0, "Time to delay syncing directories");
 static int metadelay = 28;		/* time to delay syncing metadata */
-SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0, "");
+SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0, "Time to delay syncing metadata");
 static int rushjob;		/* number of slots to run ASAP */
 static int stat_rush_requests;	/* number of times I/O speeded up */
-SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0, "");
+SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0, "Number of times I/O speeded up (rush requests)");
 
 /*
  * When shutting down the syncer, run it at four times normal speed.
@@ -533,7 +534,11 @@
 
 static int timestamp_precision = TSP_SEC;
 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
-    &timestamp_precision, 0, "");
+    &timestamp_precision, 0, "Knob to control the precision of file timestamps\n"
+	"0 = seconds only; nanoseconds zeroed\n"
+	"1 = seconds and nanoseconds, accurate within 1/HZ\n"
+	"2 = seconds and nanoseconds, truncated to microseconds\n"
+	">=3 = seconds and nanoseconds, maximum precision");
 
 /*
  * Get a current timestamp.
@@ -2357,7 +2362,7 @@
  */
 #ifdef DIAGNOSTIC
 static int busyprt = 0;		/* print out busy vnodes */
-SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "");
+SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "print out busy vnodes");
 #endif
 
 int
@@ -3666,17 +3671,17 @@
 	(vp)->v_type == VCHR ||	(vp)->v_type == VBAD)
 
 int vfs_badlock_ddb = 1;	/* Drop into debugger on violation. */
-SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_ddb, CTLFLAG_RW, &vfs_badlock_ddb, 0, "");
+SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_ddb, CTLFLAG_RW, &vfs_badlock_ddb, 0, "Drop into debugger on violation");
 
 int vfs_badlock_mutex = 1;	/* Check for interlock across VOPs. */
-SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_mutex, CTLFLAG_RW, &vfs_badlock_mutex, 0, "");
+SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_mutex, CTLFLAG_RW, &vfs_badlock_mutex, 0, "Check for interlock across VOPs");
 
 int vfs_badlock_print = 1;	/* Print lock violations. */
-SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_print, CTLFLAG_RW, &vfs_badlock_print, 0, "");
+SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_print, CTLFLAG_RW, &vfs_badlock_print, 0, "Print lock violations");
 
 #ifdef KDB
 int vfs_badlock_backtrace = 1;	/* Print backtrace at lock violations. */
-SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_backtrace, CTLFLAG_RW, &vfs_badlock_backtrace, 0, "");
+SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_backtrace, CTLFLAG_RW, &vfs_badlock_backtrace, 0, "Print backtrace at lock violations");
 #endif
 
 static void


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