Avoid dynamic syscall overhead for statically compiled modules.

The kernel tracks syscall users so that modules can safely unregister them.

But if the module is not unloadable or was compiled into the kernel, there is
no need to do this.

Achieve this by adding SY_THR_STATIC_KLD macro which expands to SY_THR_STATIC
during kernel build and 0 otherwise.

Reviewed by:	kib (previous version)
MFC after:	2 weeks

1 files changed, 8 insertions, 2 deletions

diff --git a/sys/sys/sysent.h b/sys/sys/sysent.h
index 0f1c256..dabc8e8 100644
--- a/sys/sys/sysent.h
+++ b/sys/sys/sysent.h
@@ -76,6 +76,12 @@ struct sysent {			/* system call table */
 #define	SY_THR_ABSENT	0x4
 #define	SY_THR_INCR	0x8
 
+#ifdef KLD_MODULE
+#define	SY_THR_STATIC_KLD	0
+#else
+#define	SY_THR_STATIC_KLD	SY_THR_STATIC
+#endif
+
 struct image_params;
 struct __sigset;
 struct syscall_args;
@@ -242,10 +248,10 @@ struct syscall_helper_data {
 }
 
 int	syscall_register(int *offset, struct sysent *new_sysent,
-	    struct sysent *old_sysent);
+	    struct sysent *old_sysent, int flags);
 int	syscall_deregister(int *offset, struct sysent *old_sysent);
 int	syscall_module_handler(struct module *mod, int what, void *arg);
-int	syscall_helper_register(struct syscall_helper_data *sd);
+int	syscall_helper_register(struct syscall_helper_data *sd, int flags);
 int	syscall_helper_unregister(struct syscall_helper_data *sd);
 
 struct proc;