Messages in this thread Patch in this message | | | From | Robin Holt <> | Subject | [PATCH -v5 5/5] Make reboot_cpuid a kernel parameter. | Date | Wed, 17 Apr 2013 13:43:18 -0500 |
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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 <holt@sgi.com> To: Ingo Molnar <mingo@redhat.com> To: Russ Anderson <rja@sgi.com> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org> Cc: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Robin Holt <holt@sgi.com> Cc: "rusty@rustcorp.com.au" <rusty@rustcorp.com.au> Cc: Tejun Heo <tj@kernel.org> Cc: the arch/x86 maintainers <x86@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> --- Documentation/kernel-parameters.txt | 2 ++ arch/x86/kernel/reboot.c | 39 +++++++++++++------------------------ kernel/reboot.c | 6 +++++- 3 files changed, 20 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 c4eb2a4..04a162a 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> @@ -69,10 +70,13 @@ 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); + static 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; cpu_hotplug_disable(); -- 1.8.1.2
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