From: Nick Piggin <nickpiggin@yahoo.com.au>
Add a CPU_DOWN_PREPARE hotplug CPU notifier. This is needed so we can dettach
all sched-domains before a CPU goes down, thus we can build domains from
online cpumasks, and not have to check for the possibility of a CPU coming up
or going down.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/include/linux/notifier.h | 9 +++++----
25-akpm/kernel/cpu.c | 9 +++++++++
2 files changed, 14 insertions(+), 4 deletions(-)
diff -puN include/linux/notifier.h~sched-add-cpu_down_prepare-notifier include/linux/notifier.h
--- 25/include/linux/notifier.h~sched-add-cpu_down_prepare-notifier 2004-09-08 23:37:04.172355496 -0700
+++ 25-akpm/include/linux/notifier.h 2004-09-08 23:37:04.177354736 -0700
@@ -60,10 +60,11 @@ extern int notifier_call_chain(struct no
#define NETLINK_URELEASE 0x0001 /* Unicast netlink socket released */
-#define CPU_ONLINE 0x0002 /* CPU (unsigned)v is up */
-#define CPU_UP_PREPARE 0x0003 /* CPU (unsigned)v coming up */
-#define CPU_UP_CANCELED 0x0004 /* CPU (unsigned)v NOT coming up */
-#define CPU_DEAD 0x0006 /* CPU (unsigned)v dead */
+#define CPU_ONLINE 0x0002 /* CPU (unsigned)v is up */
+#define CPU_UP_PREPARE 0x0003 /* CPU (unsigned)v coming up */
+#define CPU_UP_CANCELED 0x0004 /* CPU (unsigned)v NOT coming up */
+#define CPU_DOWN_PREPARE 0x0005 /* CPU (unsigned)v going down */
+#define CPU_DEAD 0x0006 /* CPU (unsigned)v dead */
#endif /* __KERNEL__ */
#endif /* _LINUX_NOTIFIER_H */
diff -puN kernel/cpu.c~sched-add-cpu_down_prepare-notifier kernel/cpu.c
--- 25/kernel/cpu.c~sched-add-cpu_down_prepare-notifier 2004-09-08 23:37:04.174355192 -0700
+++ 25-akpm/kernel/cpu.c 2004-09-08 23:37:04.178354584 -0700
@@ -123,6 +123,15 @@ int cpu_down(unsigned int cpu)
goto out;
}
+ err = notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE,
+ (void *)(long)cpu);
+ if (err == NOTIFY_BAD) {
+ printk("%s: attempt to take down CPU %u failed\n",
+ __FUNCTION__, cpu);
+ err = -EINVAL;
+ goto out;
+ }
+
/* Ensure that we are not runnable on dying cpu */
old_allowed = current->cpus_allowed;
tmp = CPU_MASK_ALL;
_