[src/trunk]: src/sys/kern Make the auto-unload timeout configurable via sysct...

[pgoyette <pgoyette%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/2d16af44206d
branches:  trunk
changeset: 792007:2d16af44206d
user:      pgoyette <pgoyette%NetBSD.org@localhost>
date:      Sun Dec 15 21:09:50 2013 +0000

description:
Make the auto-unload timeout configurable via sysctl, and if the timeout
is set to zero, disable all auto-unloads (even those that were "scheduled"
previously).

diffstat:

 sys/kern/kern_module.c |  44 ++++++++++++++++++++++++++++++++++++++------
 1 files changed, 38 insertions(+), 6 deletions(-)

diffs (102 lines):

diff -r e9a9807cd6aa -r 2d16af44206d sys/kern/kern_module.c
--- a/sys/kern/kern_module.c    Sun Dec 15 18:56:59 2013 +0000
+++ b/sys/kern/kern_module.c    Sun Dec 15 21:09:50 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_module.c,v 1.93 2013/09/13 07:18:34 jnemeth Exp $ */
+/*     $NetBSD: kern_module.c,v 1.94 2013/12/15 21:09:50 pgoyette Exp $        */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_module.c,v 1.93 2013/09/13 07:18:34 jnemeth Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_module.c,v 1.94 2013/12/15 21:09:50 pgoyette Exp $");
 
 #define _MODULE_INTERNAL
 
@@ -99,6 +99,8 @@
 static bool    module_merge_dicts(prop_dictionary_t, const prop_dictionary_t);
 
 static void    sysctl_module_setup(void);
+static int     sysctl_module_autotime(SYSCTLFN_PROTO);
+
 #define MODULE_CLASS_MATCH(mi, class) \
        ((class) == MODULE_CLASS_ANY || (class) == (mi)->mi_class)
 
@@ -405,6 +407,27 @@
 
 static struct sysctllog *module_sysctllog;
 
+static int
+sysctl_module_autotime(SYSCTLFN_ARGS)
+{
+       struct sysctlnode node;
+       int t, error;
+
+       t = *(int *)rnode->sysctl_data;
+
+       node = *rnode;
+       node.sysctl_data = &t;
+       error = sysctl_lookup(SYSCTLFN_CALL(&node));
+       if (error || newp == NULL)
+               return (error);
+
+       if (t < 0)
+               return (EINVAL);
+
+       *(int *)rnode->sysctl_data = t;
+       return (0);
+}
+
 static void
 sysctl_module_setup(void)
 {
@@ -437,6 +460,12 @@
                SYSCTL_DESCR("Enable verbose output"),
                NULL, 0, &module_verbose_on, 0,
                CTL_CREATE, CTL_EOL);
+       sysctl_createv(&module_sysctllog, 0, &node, NULL,
+               CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
+               CTLTYPE_INT, "autotime",
+               SYSCTL_DESCR("Auto-unload delay"),
+               sysctl_module_autotime, 0, &module_autotime, 0,
+               CTL_CREATE, CTL_EOL);
 }
 
 /*
@@ -1107,10 +1136,10 @@
        if (modp != NULL) {
                *modp = mod;
        }
-       if (autoload) {
+       if (autoload && module_autotime > 0) {
                /*
                 * Arrange to try unloading the module after
-                * a short delay.
+                * a short delay unless auto-unload is disabled.
                 */
                mod->mod_autotime = time_second + module_autotime;
                mod->mod_flags |= MODFLG_AUTO_LOADED;
@@ -1288,7 +1317,9 @@
  *
  *     Automatically unload modules.  We try once to unload autoloaded
  *     modules after module_autotime seconds.  If the system is under
- *     severe memory pressure, we'll try unloading all modules.
+ *     severe memory pressure, we'll try unloading all modules, else if
+ *     module_autotime is zero, we don't try to unload, even if the
+ *     module was previously scheduled for unload.
  */
 static void
 module_thread(void *cookie)
@@ -1311,7 +1342,8 @@
 
                        if (uvmexp.free < uvmexp.freemin) {
                                module_thread_ticks = hz;
-                       } else if (mod->mod_autotime == 0) {
+                       } else if (module_autotime == 0 ||
+                                  mod->mod_autotime == 0) {
                                continue;
                        } else if (time_second < mod->mod_autotime) {
                                module_thread_ticks = hz;