We usually don't break working user setups as a matter if policy. Only if it can't be avoided.
Robin Holt <[email protected]> wrote: >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. Please excuse brevity and lack of >formatting. -- Sent from my mobile phone. Please excuse brevity and lack of formatting. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
