We recently noticed that reboot of a 1024 cpu machine takes approx 16
minutes of just stopping the cpus. The slowdown was tracked to commit
f96972f.
The current implementation does all the work of hot removing the cpus
before halting the system. We are switching to just migrating to the
reboot_cpuid and then continuing with shutdown/reboot.
The patch set is broken into four parts. The first is planned for
the stable release. The others move the halt/shutdown/reboot related
functions to their own kernel/reboot.c file and then introduce the kernel
boot parameter.
Changes since -v3.
- Added a tested-by for the original reporter.
- Fix compile failure found by Joe Perches.
- Integrated comments by Joe Perches.
This patch is preparatory. It moves reboot related syscall, etc
functions from kernel/sys.c to kernel/reboot.c.
Signed-off-by: Robin Holt <[email protected]>
To: Ingo Molnar <[email protected]>
To: Russ Anderson <[email protected]>
Cc: Shawn Guo <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Linux Kernel Mailing List <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Robin Holt <[email protected]>
Cc: "[email protected]" <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: the arch/x86 maintainers <[email protected]>
Cc: Thomas Gleixner <[email protected]>
---
Changes since -v2
- Add #include to allow building with CONFIG_HIBERNATE
kernel/Makefile | 2 +-
kernel/reboot.c | 329 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
kernel/sys.c | 315 -----------------------------------------------------
3 files changed, 330 insertions(+), 316 deletions(-)
create mode 100644 kernel/reboot.c
diff --git a/kernel/Makefile b/kernel/Makefile
index bbde5f1..5c2cef7 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -9,7 +9,7 @@ obj-y = fork.o exec_domain.o panic.o printk.o \
rcupdate.o extable.o params.o posix-timers.o \
kthread.o wait.o sys_ni.o posix-cpu-timers.o mutex.o \
hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \
- notifier.o ksysfs.o cred.o \
+ notifier.o ksysfs.o cred.o reboot.o \
async.o range.o groups.o lglock.o smpboot.o
ifdef CONFIG_FUNCTION_TRACER
diff --git a/kernel/reboot.c b/kernel/reboot.c
new file mode 100644
index 0000000..907ab48
--- /dev/null
+++ b/kernel/reboot.c
@@ -0,0 +1,329 @@
+/*
+ * linux/kernel/sys.c
+ *
+ * Copyright (C) 2013 Linus Torvalds
+ */
+
+#include <linux/export.h>
+#include <linux/kexec.h>
+#include <linux/kmod.h>
+#include <linux/kmsg_dump.h>
+#include <linux/reboot.h>
+#include <linux/suspend.h>
+#include <linux/syscalls.h>
+#include <linux/syscore_ops.h>
+
+/**
+ * emergency_restart - reboot the system
+ *
+ * Without shutting down any hardware or taking any locks
+ * reboot the system. This is called when we know we are in
+ * trouble so this is our best effort to reboot. This is
+ * safe to call in interrupt context.
+ */
+void emergency_restart(void)
+{
+ kmsg_dump(KMSG_DUMP_EMERG);
+ machine_emergency_restart();
+}
+EXPORT_SYMBOL_GPL(emergency_restart);
+
+void kernel_restart_prepare(char *cmd)
+{
+ blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
+ system_state = SYSTEM_RESTART;
+ usermodehelper_disable();
+ device_shutdown();
+}
+
+/**
+ * register_reboot_notifier - Register function to be called at reboot time
+ * @nb: Info about notifier function to be called
+ *
+ * Registers a function with the list of functions
+ * to be called at reboot time.
+ *
+ * Currently always returns zero, as blocking_notifier_chain_register()
+ * always returns zero.
+ */
+int register_reboot_notifier(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_register(&reboot_notifier_list, nb);
+}
+EXPORT_SYMBOL(register_reboot_notifier);
+
+/**
+ * unregister_reboot_notifier - Unregister previously registered reboot notifier
+ * @nb: Hook to be unregistered
+ *
+ * Unregisters a previously registered reboot
+ * notifier function.
+ *
+ * Returns zero on success, or %-ENOENT on failure.
+ */
+int unregister_reboot_notifier(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
+}
+EXPORT_SYMBOL(unregister_reboot_notifier);
+
+void migrate_to_reboot_cpu(void)
+{
+ /* The boot cpu is always logical cpu 0 */
+ int reboot_cpu_id = 0;
+
+ /* Make certain the cpu I'm about to reboot on is online */
+ if (!cpu_online(reboot_cpu_id))
+ reboot_cpu_id = smp_processor_id();
+
+ /* Prevent races with other tasks migrating this task. */
+ current->flags |= PF_THREAD_BOUND;
+
+ /* Make certain I only run on the appropriate processor */
+ set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
+}
+
+/**
+ * kernel_restart - reboot the system
+ * @cmd: pointer to buffer containing command to execute for restart
+ * or %NULL
+ *
+ * Shutdown everything and perform a clean reboot.
+ * This is not safe to call in interrupt context.
+ */
+void kernel_restart(char *cmd)
+{
+ kernel_restart_prepare(cmd);
+ migrate_to_reboot_cpu();
+ syscore_shutdown();
+ if (!cmd)
+ printk(KERN_EMERG "Restarting system.\n");
+ else
+ printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
+ kmsg_dump(KMSG_DUMP_RESTART);
+ machine_restart(cmd);
+}
+EXPORT_SYMBOL_GPL(kernel_restart);
+
+static void kernel_shutdown_prepare(enum system_states state)
+{
+ blocking_notifier_call_chain(&reboot_notifier_list,
+ (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
+ system_state = state;
+ usermodehelper_disable();
+ device_shutdown();
+}
+/**
+ * kernel_halt - halt the system
+ *
+ * Shutdown everything and perform a clean system halt.
+ */
+void kernel_halt(void)
+{
+ kernel_shutdown_prepare(SYSTEM_HALT);
+ migrate_to_reboot_cpu();
+ syscore_shutdown();
+ printk(KERN_EMERG "System halted.\n");
+ kmsg_dump(KMSG_DUMP_HALT);
+ machine_halt();
+}
+
+EXPORT_SYMBOL_GPL(kernel_halt);
+
+/**
+ * kernel_power_off - power_off the system
+ *
+ * Shutdown everything and perform a clean system power_off.
+ */
+void kernel_power_off(void)
+{
+ kernel_shutdown_prepare(SYSTEM_POWER_OFF);
+ if (pm_power_off_prepare)
+ pm_power_off_prepare();
+ migrate_to_reboot_cpu();
+ syscore_shutdown();
+ printk(KERN_EMERG "Power down.\n");
+ kmsg_dump(KMSG_DUMP_POWEROFF);
+ machine_power_off();
+}
+EXPORT_SYMBOL_GPL(kernel_power_off);
+
+static DEFINE_MUTEX(reboot_mutex);
+
+/*
+ * Reboot system call: for obvious reasons only root may call it,
+ * and even root needs to set up some magic numbers in the registers
+ * so that some mistake won't make this reboot the whole machine.
+ * You can also set the meaning of the ctrl-alt-del-key here.
+ *
+ * reboot doesn't sync: do that yourself before calling this.
+ */
+SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
+ void __user *, arg)
+{
+ struct pid_namespace *pid_ns = task_active_pid_ns(current);
+ char buffer[256];
+ int ret = 0;
+
+ /* We only trust the superuser with rebooting the system. */
+ if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
+ return -EPERM;
+
+ /* For safety, we require "magic" arguments. */
+ if (magic1 != LINUX_REBOOT_MAGIC1 ||
+ (magic2 != LINUX_REBOOT_MAGIC2 &&
+ magic2 != LINUX_REBOOT_MAGIC2A &&
+ magic2 != LINUX_REBOOT_MAGIC2B &&
+ magic2 != LINUX_REBOOT_MAGIC2C))
+ return -EINVAL;
+
+ /*
+ * If pid namespaces are enabled and the current task is in a child
+ * pid_namespace, the command is handled by reboot_pid_ns() which will
+ * call do_exit().
+ */
+ ret = reboot_pid_ns(pid_ns, cmd);
+ if (ret)
+ return ret;
+
+ /* Instead of trying to make the power_off code look like
+ * halt when pm_power_off is not set do it the easy way.
+ */
+ if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
+ cmd = LINUX_REBOOT_CMD_HALT;
+
+ mutex_lock(&reboot_mutex);
+ switch (cmd) {
+ case LINUX_REBOOT_CMD_RESTART:
+ kernel_restart(NULL);
+ break;
+
+ case LINUX_REBOOT_CMD_CAD_ON:
+ C_A_D = 1;
+ break;
+
+ case LINUX_REBOOT_CMD_CAD_OFF:
+ C_A_D = 0;
+ break;
+
+ case LINUX_REBOOT_CMD_HALT:
+ kernel_halt();
+ do_exit(0);
+ panic("cannot halt");
+
+ case LINUX_REBOOT_CMD_POWER_OFF:
+ kernel_power_off();
+ do_exit(0);
+ break;
+
+ case LINUX_REBOOT_CMD_RESTART2:
+ if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
+ ret = -EFAULT;
+ break;
+ }
+ buffer[sizeof(buffer) - 1] = '\0';
+
+ kernel_restart(buffer);
+ break;
+
+#ifdef CONFIG_KEXEC
+ case LINUX_REBOOT_CMD_KEXEC:
+ ret = kernel_kexec();
+ break;
+#endif
+
+#ifdef CONFIG_HIBERNATION
+ case LINUX_REBOOT_CMD_SW_SUSPEND:
+ ret = hibernate();
+ break;
+#endif
+
+ default:
+ ret = -EINVAL;
+ break;
+ }
+ mutex_unlock(&reboot_mutex);
+ return ret;
+}
+
+static void deferred_cad(struct work_struct *dummy)
+{
+ kernel_restart(NULL);
+}
+
+/*
+ * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
+ * As it's called within an interrupt, it may NOT sync: the only choice
+ * is whether to reboot at once, or just ignore the ctrl-alt-del.
+ */
+void ctrl_alt_del(void)
+{
+ static DECLARE_WORK(cad_work, deferred_cad);
+
+ if (C_A_D)
+ schedule_work(&cad_work);
+ else
+ kill_cad_pid(SIGINT, 1);
+}
+
+char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
+
+static int __orderly_poweroff(bool force)
+{
+ char **argv;
+ static char *envp[] = {
+ "HOME=/",
+ "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
+ NULL
+ };
+ int ret;
+
+ argv = argv_split(GFP_KERNEL, poweroff_cmd, NULL);
+ if (argv) {
+ ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+ argv_free(argv);
+ } else {
+ printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
+ __func__, poweroff_cmd);
+ ret = -ENOMEM;
+ }
+
+ if (ret && force) {
+ printk(KERN_WARNING "Failed to start orderly shutdown: "
+ "forcing the issue\n");
+ /*
+ * I guess this should try to kick off some daemon to sync and
+ * poweroff asap. Or not even bother syncing if we're doing an
+ * emergency shutdown?
+ */
+ emergency_sync();
+ kernel_power_off();
+ }
+
+ return ret;
+}
+
+static bool poweroff_force;
+
+static void poweroff_work_func(struct work_struct *work)
+{
+ __orderly_poweroff(poweroff_force);
+}
+
+static DECLARE_WORK(poweroff_work, poweroff_work_func);
+
+/**
+ * orderly_poweroff - Trigger an orderly system poweroff
+ * @force: force poweroff if command execution fails
+ *
+ * This may be called from any context to trigger a system shutdown.
+ * If the orderly shutdown fails, it will force an immediate shutdown.
+ */
+int orderly_poweroff(bool force)
+{
+ if (force) /* do not override the pending "true" */
+ poweroff_force = true;
+ schedule_work(&poweroff_work);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(orderly_poweroff);
diff --git a/kernel/sys.c b/kernel/sys.c
index 5ef7aa2..76b9a93 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -303,259 +303,6 @@ out_unlock:
return retval;
}
-/**
- * emergency_restart - reboot the system
- *
- * Without shutting down any hardware or taking any locks
- * reboot the system. This is called when we know we are in
- * trouble so this is our best effort to reboot. This is
- * safe to call in interrupt context.
- */
-void emergency_restart(void)
-{
- kmsg_dump(KMSG_DUMP_EMERG);
- machine_emergency_restart();
-}
-EXPORT_SYMBOL_GPL(emergency_restart);
-
-void kernel_restart_prepare(char *cmd)
-{
- blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
- system_state = SYSTEM_RESTART;
- usermodehelper_disable();
- device_shutdown();
-}
-
-/**
- * register_reboot_notifier - Register function to be called at reboot time
- * @nb: Info about notifier function to be called
- *
- * Registers a function with the list of functions
- * to be called at reboot time.
- *
- * Currently always returns zero, as blocking_notifier_chain_register()
- * always returns zero.
- */
-int register_reboot_notifier(struct notifier_block *nb)
-{
- return blocking_notifier_chain_register(&reboot_notifier_list, nb);
-}
-EXPORT_SYMBOL(register_reboot_notifier);
-
-/**
- * unregister_reboot_notifier - Unregister previously registered reboot notifier
- * @nb: Hook to be unregistered
- *
- * Unregisters a previously registered reboot
- * notifier function.
- *
- * Returns zero on success, or %-ENOENT on failure.
- */
-int unregister_reboot_notifier(struct notifier_block *nb)
-{
- return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
-}
-EXPORT_SYMBOL(unregister_reboot_notifier);
-
-void migrate_to_reboot_cpu(void)
-{
- /* The boot cpu is always logical cpu 0 */
- int reboot_cpu_id = 0;
-
- /* Make certain the cpu I'm about to reboot on is online */
- if (!cpu_online(reboot_cpu_id))
- reboot_cpu_id = smp_processor_id();
-
- /* Prevent races with other tasks migrating this task. */
- current->flags |= PF_THREAD_BOUND;
-
- /* Make certain I only run on the appropriate processor */
- set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
-}
-
-/**
- * kernel_restart - reboot the system
- * @cmd: pointer to buffer containing command to execute for restart
- * or %NULL
- *
- * Shutdown everything and perform a clean reboot.
- * This is not safe to call in interrupt context.
- */
-void kernel_restart(char *cmd)
-{
- kernel_restart_prepare(cmd);
- migrate_to_reboot_cpu();
- syscore_shutdown();
- if (!cmd)
- printk(KERN_EMERG "Restarting system.\n");
- else
- printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
- kmsg_dump(KMSG_DUMP_RESTART);
- machine_restart(cmd);
-}
-EXPORT_SYMBOL_GPL(kernel_restart);
-
-static void kernel_shutdown_prepare(enum system_states state)
-{
- blocking_notifier_call_chain(&reboot_notifier_list,
- (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
- system_state = state;
- usermodehelper_disable();
- device_shutdown();
-}
-/**
- * kernel_halt - halt the system
- *
- * Shutdown everything and perform a clean system halt.
- */
-void kernel_halt(void)
-{
- kernel_shutdown_prepare(SYSTEM_HALT);
- migrate_to_reboot_cpu();
- syscore_shutdown();
- printk(KERN_EMERG "System halted.\n");
- kmsg_dump(KMSG_DUMP_HALT);
- machine_halt();
-}
-
-EXPORT_SYMBOL_GPL(kernel_halt);
-
-/**
- * kernel_power_off - power_off the system
- *
- * Shutdown everything and perform a clean system power_off.
- */
-void kernel_power_off(void)
-{
- kernel_shutdown_prepare(SYSTEM_POWER_OFF);
- if (pm_power_off_prepare)
- pm_power_off_prepare();
- migrate_to_reboot_cpu();
- syscore_shutdown();
- printk(KERN_EMERG "Power down.\n");
- kmsg_dump(KMSG_DUMP_POWEROFF);
- machine_power_off();
-}
-EXPORT_SYMBOL_GPL(kernel_power_off);
-
-static DEFINE_MUTEX(reboot_mutex);
-
-/*
- * Reboot system call: for obvious reasons only root may call it,
- * and even root needs to set up some magic numbers in the registers
- * so that some mistake won't make this reboot the whole machine.
- * You can also set the meaning of the ctrl-alt-del-key here.
- *
- * reboot doesn't sync: do that yourself before calling this.
- */
-SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
- void __user *, arg)
-{
- struct pid_namespace *pid_ns = task_active_pid_ns(current);
- char buffer[256];
- int ret = 0;
-
- /* We only trust the superuser with rebooting the system. */
- if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
- return -EPERM;
-
- /* For safety, we require "magic" arguments. */
- if (magic1 != LINUX_REBOOT_MAGIC1 ||
- (magic2 != LINUX_REBOOT_MAGIC2 &&
- magic2 != LINUX_REBOOT_MAGIC2A &&
- magic2 != LINUX_REBOOT_MAGIC2B &&
- magic2 != LINUX_REBOOT_MAGIC2C))
- return -EINVAL;
-
- /*
- * If pid namespaces are enabled and the current task is in a child
- * pid_namespace, the command is handled by reboot_pid_ns() which will
- * call do_exit().
- */
- ret = reboot_pid_ns(pid_ns, cmd);
- if (ret)
- return ret;
-
- /* Instead of trying to make the power_off code look like
- * halt when pm_power_off is not set do it the easy way.
- */
- if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
- cmd = LINUX_REBOOT_CMD_HALT;
-
- mutex_lock(&reboot_mutex);
- switch (cmd) {
- case LINUX_REBOOT_CMD_RESTART:
- kernel_restart(NULL);
- break;
-
- case LINUX_REBOOT_CMD_CAD_ON:
- C_A_D = 1;
- break;
-
- case LINUX_REBOOT_CMD_CAD_OFF:
- C_A_D = 0;
- break;
-
- case LINUX_REBOOT_CMD_HALT:
- kernel_halt();
- do_exit(0);
- panic("cannot halt");
-
- case LINUX_REBOOT_CMD_POWER_OFF:
- kernel_power_off();
- do_exit(0);
- break;
-
- case LINUX_REBOOT_CMD_RESTART2:
- if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
- ret = -EFAULT;
- break;
- }
- buffer[sizeof(buffer) - 1] = '\0';
-
- kernel_restart(buffer);
- break;
-
-#ifdef CONFIG_KEXEC
- case LINUX_REBOOT_CMD_KEXEC:
- ret = kernel_kexec();
- break;
-#endif
-
-#ifdef CONFIG_HIBERNATION
- case LINUX_REBOOT_CMD_SW_SUSPEND:
- ret = hibernate();
- break;
-#endif
-
- default:
- ret = -EINVAL;
- break;
- }
- mutex_unlock(&reboot_mutex);
- return ret;
-}
-
-static void deferred_cad(struct work_struct *dummy)
-{
- kernel_restart(NULL);
-}
-
-/*
- * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
- * As it's called within an interrupt, it may NOT sync: the only choice
- * is whether to reboot at once, or just ignore the ctrl-alt-del.
- */
-void ctrl_alt_del(void)
-{
- static DECLARE_WORK(cad_work, deferred_cad);
-
- if (C_A_D)
- schedule_work(&cad_work);
- else
- kill_cad_pid(SIGINT, 1);
-}
-
/*
* Unprivileged users may change the real gid to the effective gid
* or vice versa. (BSD-style)
@@ -2199,65 +1946,3 @@ SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
err |= put_user(cpu_to_node(cpu), nodep);
return err ? -EFAULT : 0;
}
-
-char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
-
-static int __orderly_poweroff(bool force)
-{
- char **argv;
- static char *envp[] = {
- "HOME=/",
- "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
- NULL
- };
- int ret;
-
- argv = argv_split(GFP_KERNEL, poweroff_cmd, NULL);
- if (argv) {
- ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
- argv_free(argv);
- } else {
- printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
- __func__, poweroff_cmd);
- ret = -ENOMEM;
- }
-
- if (ret && force) {
- printk(KERN_WARNING "Failed to start orderly shutdown: "
- "forcing the issue\n");
- /*
- * I guess this should try to kick off some daemon to sync and
- * poweroff asap. Or not even bother syncing if we're doing an
- * emergency shutdown?
- */
- emergency_sync();
- kernel_power_off();
- }
-
- return ret;
-}
-
-static bool poweroff_force;
-
-static void poweroff_work_func(struct work_struct *work)
-{
- __orderly_poweroff(poweroff_force);
-}
-
-static DECLARE_WORK(poweroff_work, poweroff_work_func);
-
-/**
- * orderly_poweroff - Trigger an orderly system poweroff
- * @force: force poweroff if command execution fails
- *
- * This may be called from any context to trigger a system shutdown.
- * If the orderly shutdown fails, it will force an immediate shutdown.
- */
-int orderly_poweroff(bool force)
-{
- if (force) /* do not override the pending "true" */
- poweroff_force = true;
- schedule_work(&poweroff_work);
- return 0;
-}
-EXPORT_SYMBOL_GPL(orderly_poweroff);
--
1.8.1.2
I did allow the remaining 81 character line behind. It did not seem
like it was worth changing. Otherwise, it now passes checkpatch.pl.
Signed-off-by: Robin Holt <[email protected]>
To: Ingo Molnar <[email protected]>
To: Russ Anderson <[email protected]>
Cc: Shawn Guo <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Linux Kernel Mailing List <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Robin Holt <[email protected]>
Cc: "[email protected]" <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: the arch/x86 maintainers <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Joe Perches <[email protected]>
---
Changes since -v3:
- Integrated feedback from Joe Perches.
kernel/reboot.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 907ab48..8cfef20 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -1,9 +1,11 @@
/*
- * linux/kernel/sys.c
+ * linux/kernel/reboot.c
*
* Copyright (C) 2013 Linus Torvalds
*/
+#define pr_fmt(fmt) "reboot: " fmt
+
#include <linux/export.h>
#include <linux/kexec.h>
#include <linux/kmod.h>
@@ -97,9 +99,9 @@ void kernel_restart(char *cmd)
migrate_to_reboot_cpu();
syscore_shutdown();
if (!cmd)
- printk(KERN_EMERG "Restarting system.\n");
+ pr_emerg("Restarting system\n");
else
- printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
+ pr_emerg("Restarting system with command '%s'\n", cmd);
kmsg_dump(KMSG_DUMP_RESTART);
machine_restart(cmd);
}
@@ -108,7 +110,7 @@ EXPORT_SYMBOL_GPL(kernel_restart);
static void kernel_shutdown_prepare(enum system_states state)
{
blocking_notifier_call_chain(&reboot_notifier_list,
- (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
+ (state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL);
system_state = state;
usermodehelper_disable();
device_shutdown();
@@ -123,11 +125,10 @@ void kernel_halt(void)
kernel_shutdown_prepare(SYSTEM_HALT);
migrate_to_reboot_cpu();
syscore_shutdown();
- printk(KERN_EMERG "System halted.\n");
+ pr_emerg("System halted\n");
kmsg_dump(KMSG_DUMP_HALT);
machine_halt();
}
-
EXPORT_SYMBOL_GPL(kernel_halt);
/**
@@ -142,7 +143,7 @@ void kernel_power_off(void)
pm_power_off_prepare();
migrate_to_reboot_cpu();
syscore_shutdown();
- printk(KERN_EMERG "Power down.\n");
+ pr_emerg("Power down\n");
kmsg_dump(KMSG_DUMP_POWEROFF);
machine_power_off();
}
@@ -171,10 +172,10 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
/* For safety, we require "magic" arguments. */
if (magic1 != LINUX_REBOOT_MAGIC1 ||
- (magic2 != LINUX_REBOOT_MAGIC2 &&
- magic2 != LINUX_REBOOT_MAGIC2A &&
+ (magic2 != LINUX_REBOOT_MAGIC2 &&
+ magic2 != LINUX_REBOOT_MAGIC2A &&
magic2 != LINUX_REBOOT_MAGIC2B &&
- magic2 != LINUX_REBOOT_MAGIC2C))
+ magic2 != LINUX_REBOOT_MAGIC2C))
return -EINVAL;
/*
@@ -283,14 +284,13 @@ static int __orderly_poweroff(bool force)
ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
argv_free(argv);
} else {
- printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
- __func__, poweroff_cmd);
+ pr_warn("%s failed to allocate memory for \"%s\"\n",
+ __func__, poweroff_cmd);
ret = -ENOMEM;
}
if (ret && force) {
- printk(KERN_WARNING "Failed to start orderly shutdown: "
- "forcing the issue\n");
+ pr_warn("Failed to start orderly shutdown: forcing the issue\n");
/*
* I guess this should try to kick off some daemon to sync and
* poweroff asap. Or not even bother syncing if we're doing an
--
1.8.1.2
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 <[email protected]>
To: Ingo Molnar <[email protected]>
To: Russ Anderson <[email protected]>
Cc: Shawn Guo <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Linux Kernel Mailing List <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Robin Holt <[email protected]>
Cc: "[email protected]" <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: the arch/x86 maintainers <[email protected]>
Cc: Thomas Gleixner <[email protected]>
---
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
Why not just support the existing syntax everywhere?
Robin Holt <[email protected]> wrote:
>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 <[email protected]>
>To: Ingo Molnar <[email protected]>
>To: Russ Anderson <[email protected]>
>Cc: Shawn Guo <[email protected]>
>Cc: Oleg Nesterov <[email protected]>
>Cc: Andrew Morton <[email protected]>
>Cc: "H. Peter Anvin" <[email protected]>
>Cc: Lai Jiangshan <[email protected]>
>Cc: Linus Torvalds <[email protected]>
>Cc: Linux Kernel Mailing List <[email protected]>
>Cc: Michel Lespinasse <[email protected]>
>Cc: Oleg Nesterov <[email protected]>
>Cc: "Paul E. McKenney" <[email protected]>
>Cc: Paul Mackerras <[email protected]>
>Cc: Peter Zijlstra <[email protected]>
>Cc: Robin Holt <[email protected]>
>Cc: "[email protected]" <[email protected]>
>Cc: Tejun Heo <[email protected]>
>Cc: the arch/x86 maintainers <[email protected]>
>Cc: Thomas Gleixner <[email protected]>
>
>---
>
>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. */
--
Sent from my mobile phone. Please excuse brevity and lack of formatting.
On Tue, Apr 16, 2013 at 05:05:45AM -0700, H. Peter Anvin wrote:
> Why not just support the existing syntax everywhere?
I have not given it much consideration, but IIRC, the other arches that
were using reboot= were only looking for an 'h' or something like that.
I will consider making the syntax parse reboot=s#### when I get to
the office.
Robin
>
> Robin Holt <[email protected]> wrote:
>
> >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 <[email protected]>
> >To: Ingo Molnar <[email protected]>
> >To: Russ Anderson <[email protected]>
> >Cc: Shawn Guo <[email protected]>
> >Cc: Oleg Nesterov <[email protected]>
> >Cc: Andrew Morton <[email protected]>
> >Cc: "H. Peter Anvin" <[email protected]>
> >Cc: Lai Jiangshan <[email protected]>
> >Cc: Linus Torvalds <[email protected]>
> >Cc: Linux Kernel Mailing List <[email protected]>
> >Cc: Michel Lespinasse <[email protected]>
> >Cc: Oleg Nesterov <[email protected]>
> >Cc: "Paul E. McKenney" <[email protected]>
> >Cc: Paul Mackerras <[email protected]>
> >Cc: Peter Zijlstra <[email protected]>
> >Cc: Robin Holt <[email protected]>
> >Cc: "[email protected]" <[email protected]>
> >Cc: Tejun Heo <[email protected]>
> >Cc: the arch/x86 maintainers <[email protected]>
> >Cc: Thomas Gleixner <[email protected]>
> >
> >---
> >
> >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. */
>
> --
> Sent from my mobile phone. Please excuse brevity and lack of formatting.
On Tue, Apr 16, 2013 at 07:44:12AM -0500, Robin Holt wrote:
> On Tue, Apr 16, 2013 at 05:05:45AM -0700, H. Peter Anvin wrote:
> > Why not just support the existing syntax everywhere?
>
> I have not given it much consideration, but IIRC, the other arches that
> were using reboot= were only looking for an 'h' or something like that.
>
> I will consider making the syntax parse reboot=s#### when I get to
> the office.
Yesterday was rather disruptive and I did not get to this. I have given
it some thought this morning.
Generally speaking, I don't like the feel of this for two reasons. First,
having two different places that are parsing reboot=<reboot_mode> and
its related difficulty in documenting it. Second, we lose the /sys/ file.
Some background. First, arm. It already has a reboot=<c>. That <c>
gets passed to the reboot sub-arch function. It looks like it is ignored,
but I am very uncertain of that as it is passed into an assembly routine.
Second unicore. It parses as reboot=<c>. That <c> gets ignored.
Now the meat of my question. The Documentation/kernel-parameters.txt
file indicates reboot= is handled by the arch and are of the format
<reboot-mode>[,<reboot-mode>[,...]].
I suppose we could have both an arch and generic kernel handler for
__setup("reboot=",...) where the generic kernel one just handles the
s###, but that seems really different from how everything else is done.
I could not find one instance where a both an arch and the kernel proper
both parsed the same command-line parameter.
I did not spend the time to see if having two __setup() declarations
would work.
Additionally, the __setup("... mechanism loses the nice feature the
core_param gives us in that there is a /sys/ file now available which
allows us to easily change that setting on the running system.
Are you really sure you want me to do more than I already have. This
really feels _VERY_ wrong to me. Maybe I misunderstood your direction.
Thanks,
Robin