vm_pageout: Group sysctl variables together with sysctl definitions

[markj]

Summary

Fix some style bugs while here. No functional change intended.

MFC after: 1 week

[kib]

sys/vm/vm_pageout.c

181–182

Move the description to the new line there as well?

200–201

and there?

[markj]

• Put descriptions on their own lines.
• Make whitespace consistent for all sysctls.

sys/vm/vm_pageout.c

if (cpu_vendor_id == CPU_VENDOR_INTEL && cpu_id == 0x506c9) {
                  */
                 cpu_idle_apl31_workaround = 1;
                 mwait_cpustop_broken = true;
         }
         TUNABLE_INT_FETCH("machdep.idle_apl31", &cpu_idle_apl31_workaround);
 }
 SYSINIT(cpu_idle_tun, SI_SUB_CPU, SI_ORDER_MIDDLE, cpu_idle_tun, NULL);
 
-static int panic_on_nmi = 1;
+static int panic_on_nmi = 0xff;
 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RWTUN,
     &panic_on_nmi, 0,
-    "Panic on NMI raised by hardware failure");
+    "Panic on NMI: 1 = H/W failure; 2 = unknown; 0xff = all");
 int nmi_is_broadcast = 1;
 SYSCTL_INT(_machdep, OID_AUTO, nmi_is_broadcast, CTLFLAG_RWTUN,
     &nmi_is_broadcast, 0,
     "Chipset NMI is broadcast");
-#ifdef KDB
-int kdb_on_nmi = 1;
-SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RWTUN,
-    &kdb_on_nmi, 0,
-    "Go to KDB on NMI with unknown source");
-#endif
 
 void
 nmi_call_kdb(u_int cpu, u_int type, struct trapframe *frame)
 {
         bool claimed = false;
 
 #ifdef DEV_ISA
         /* machine/parity/power fail/"kitchen sink" faults */
         if (isa_nmi(frame->tf_err)) {
                 claimed = true;
-                if (panic_on_nmi)
+                if ((panic_on_nmi & 1) != 0)
                         panic("NMI indicates hardware failure");
         }
 #endif /* DEV_ISA */
-#ifdef KDB
-        if (!claimed && kdb_on_nmi) {
-                /*
-                 * NMI can be hooked up to a pushbutton for debugging.
-                 */
+
+         * NMIs can be useful for debugging.  They can be hooked up to a
+         * pushbutton, usually on an ISA, PCI, or PCIe card.  They can also be
+         * generated by an IPMI BMC, either manually or in response to a
+         * watchdog timeout.  For example, see the "power diag" command in
+         * ports/sysutils/ipmitool.  They can also be generated by a
+         * hypervisor; see "bhyvectl --inject-nmi".
+
+#ifdef KDB
+        if (!claimed && (panic_on_nmi & 2) != 0) {
+                if (debugger_on_panic) {
                         printf("NMI/cpu%d ... going to debugger\n", cpu);
-                kdb_trap(type, 0, frame);
+                        claimed = kdb_trap(type, 0, frame);
                 }
+        }
 #endif /* KDB */
+
+        if (!claimed && panic_on_nmi != 0)
+                panic("NMI");
 }
 
 void
 nmi_handle_intr(u_int type, struct trapframe *frame)
 {
 
 #ifdef SMP
         if (nmi_is_broadcast) {