On Mon, Apr 15, 2013 at 10:18:31AM -0700, H. Peter Anvin wrote: > Um... doesn't this break anyone who currently depends on this?
Yes. That is also why I kept this separate and not tagged for stable. They would need to start using the more general kernel parameter to get the same functionality. Should I have done it differently? 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. > > > >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]> > >--- > > Documentation/kernel-parameters.txt | 2 ++ > >arch/x86/kernel/reboot.c | 44 > >++++--------------------------------- > > kernel/reboot.c | 8 ++++++- > > 3 files changed, 13 insertions(+), 41 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..39af130 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 > >@@ -64,11 +60,10 @@ static int reboot_emergency; > > bool port_cf9_safe = false; > > > > /* > >- * reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | > >[c]old] | p[ci] > >+ * reboot=b[ios] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | > >p[ci] > > * warm Don't set the cold reboot flag > > * cold Set the cold reboot flag > > * bios Reboot by jumping through the BIOS > >- * smp Reboot by executing reset on BSP or other CPU > > * triple Force a triple fault (init) > > * kbd Use the keyboard controller. cold reset (default) > > * acpi Use the RESET_REG in the FADT > >@@ -95,21 +90,6 @@ static int __init reboot_setup(char *str) > > reboot_mode = 0; > > break; > > > >-#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'); > >- } > >- /* > >- * We will leave sorting out the final value > >- * when we are ready to reboot, since we might not > >- * have detected BSP APIC ID or smp_num_cpu > >- */ > >- break; > >-#endif /* CONFIG_SMP */ > >- > > case 'b': > > case 'a': > > case 'k': > >@@ -614,26 +594,10 @@ 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 187a0d8..9fbab07 100644 > >--- a/kernel/reboot.c > >+++ b/kernel/reboot.c > >@@ -8,6 +8,7 @@ > > #include <linux/kexec.h> > > #include <linux/kmod.h> > > #include <linux/kmsg_dump.h> > >+#include <linux/moduleparam.h> > > #include <linux/reboot.h> > > #include <linux/syscalls.h> > > #include <linux/syscore_ops.h> > >@@ -66,13 +67,18 @@ int unregister_reboot_notifier(struct > >notifier_block *nb) > > } > > EXPORT_SYMBOL(unregister_reboot_notifier); > > > >+int reboot_cpuid; > >+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. 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