Moving the reboot=s<##> parameter for x86 to a kernel parameter
proper. I did not find any other arch that was specifying the
reboot cpu.
I left a compatibility mode in there. The new parameter always
takes precedence. I also fixed up the current code to support
up to cpuid's up to the current max of 4096.
Signed-off-by: Robin Holt <h...@sgi.com>
To: Ingo Molnar <mi...@redhat.com>
To: Russ Anderson <r...@sgi.com>
Cc: Shawn Guo <shawn....@linaro.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: Lai Jiangshan <la...@cn.fujitsu.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: Michel Lespinasse <wal...@google.com>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: "Paul E. McKenney" <paul...@linux.vnet.ibm.com>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Robin Holt <h...@sgi.com>
Cc: "ru...@rustcorp.com.au" <ru...@rustcorp.com.au>
Cc: Tejun Heo <t...@kernel.org>
Cc: the arch/x86 maintainers <x...@kernel.org>
Cc: Thomas Gleixner <t...@linutronix.de>
---
Changes since -v3
- Added a reboot=s#### compatibility mode for x86.
Documentation/kernel-parameters.txt | 2 ++
arch/x86/kernel/reboot.c | 39 +++++++++++++------------------------
kernel/reboot.c | 8 +++++++-
3 files changed, 22 insertions(+), 27 deletions(-)
diff --git a/Documentation/kernel-parameters.txt
b/Documentation/kernel-parameters.txt
index 4609e81..11ebb48 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2597,6 +2597,8 @@ bytes respectively. Such letter suffixes can also be
entirely omitted.
Format: <reboot_mode>[,<reboot_mode2>[,...]]
See arch/*/kernel/reboot.c or arch/*/kernel/process.c
+ reboot_cpuid= [KNL] cpuid to use for reboot/halt, etc operations.
+
relax_domain_level=
[KNL, SMP] Set scheduler's default relax_domain_level.
See Documentation/cgroups/cpusets.txt.
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 76fa1e9..cdcf28f 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -49,10 +49,6 @@ int reboot_force;
*/
static int reboot_default = 1;
-#ifdef CONFIG_SMP
-static int reboot_cpu = -1;
-#endif
-
/*
* This is set if we need to go through the 'emergency' path.
* When machine_emergency_restart() is called, we may be on
@@ -63,6 +59,8 @@ static int reboot_emergency;
/* This is set by the PCI code if either type 1 or type 2 PCI is detected */
bool port_cf9_safe = false;
+extern int reboot_cpuid;
+
/*
* reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci]
* warm Don't set the cold reboot flag
@@ -97,10 +95,14 @@ static int __init reboot_setup(char *str)
#ifdef CONFIG_SMP
case 's':
- if (isdigit(*(str+1))) {
- reboot_cpu = (int) (*(str+1) - '0');
- if (isdigit(*(str+2)))
- reboot_cpu = reboot_cpu*10 +
(int)(*(str+2) - '0');
+ if (reboot_cpuid < 0) {
+ int coffset;
+
+ reboot_cpuid = 0;
+ for (coffset = 1; isdigit(*(str + coffset));
coffset++) {
+ reboot_cpuid *= 10;
+ reboot_cpuid += (int)(*(str+2) - '0');
+ }
}
/*
* We will leave sorting out the final value
@@ -615,25 +617,10 @@ void native_machine_shutdown(void)
/* Stop the cpus and apics */
#ifdef CONFIG_SMP
- /* The boot cpu is always logical cpu 0 */
- int reboot_cpu_id = 0;
-
- /* See if there has been given a command line override */
- if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) &&
- cpu_online(reboot_cpu))
- reboot_cpu_id = reboot_cpu;
-
- /* Make certain the cpu I'm about to reboot on is online */
- if (!cpu_online(reboot_cpu_id))
- reboot_cpu_id = smp_processor_id();
-
- /* Make certain I only run on the appropriate processor */
- set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
-
/*
- * O.K Now that I'm on the appropriate processor, stop all of the
- * others. Also disable the local irq to not receive the per-cpu
- * timer interrupt which may trigger scheduler's load balance.
+ * Stop all of the others. Also disable the local irq to
+ * not receive the per-cpu timer interrupt which may trigger
+ * scheduler's load balance.
*/
local_irq_disable();
stop_other_cpus();
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 8cfef20..b2ef798 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -10,6 +10,7 @@
#include <linux/kexec.h>
#include <linux/kmod.h>
#include <linux/kmsg_dump.h>
+#include <linux/moduleparam.h>
#include <linux/reboot.h>
#include <linux/suspend.h>
#include <linux/syscalls.h>
@@ -69,13 +70,18 @@ int unregister_reboot_notifier(struct notifier_block *nb)
}
EXPORT_SYMBOL(unregister_reboot_notifier);
+int reboot_cpuid = -1;
+core_param(reboot_cpuid, reboot_cpuid, int, 0644);
+
void migrate_to_reboot_cpu(void)
{
/* The boot cpu is always logical cpu 0 */
- int reboot_cpu_id = 0;
+ int reboot_cpu_id = reboot_cpuid;
/* Make certain the cpu I'm about to reboot on is online */
if (!cpu_online(reboot_cpu_id))
+ reboot_cpu_id = 0;
+ if (!cpu_online(reboot_cpu_id))
reboot_cpu_id = smp_processor_id();
/* Prevent races with other tasks migrating this task. */
--
1.8.1.2
--
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