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| author | Uros Bizjak <ubizjak@gmail.com> | 2023-11-23 21:34:22 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-11-30 20:25:09 +0100 |
| commit | 9d1c8f21533729b6ead531b676fa7d327cf00819 (patch) | |
| tree | 0881d03fa28d8c2555adcf30a0e6bf0ed50d3deb | |
| parent | 4604c052b84d66407f5e68045a1939685eac401e (diff) | |
| download | lwn-9d1c8f21533729b6ead531b676fa7d327cf00819.tar.gz lwn-9d1c8f21533729b6ead531b676fa7d327cf00819.zip | |
x86/smp: Move the call to smp_processor_id() after the early exit in native_stop_other_cpus()
Improve code generation in native_stop_other_cpus() a tiny bit:
smp_processor_id() accesses a per-CPU variable, so the compiler
is not able to move the call after the early exit on its own.
Also rename the "cpu" variable to a more descriptive "this_cpu", and
use 'cpu' as a separate iterator variable later in the function.
No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231123203605.3474745-1-ubizjak@gmail.com
| -rw-r--r-- | arch/x86/kernel/smp.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index 6eb06d001bcc..65dd44e3fc1c 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -148,14 +148,15 @@ static int register_stop_handler(void) static void native_stop_other_cpus(int wait) { - unsigned int cpu = smp_processor_id(); + unsigned int this_cpu; unsigned long flags, timeout; if (reboot_force) return; /* Only proceed if this is the first CPU to reach this code */ - if (atomic_cmpxchg(&stopping_cpu, -1, cpu) != -1) + this_cpu = smp_processor_id(); + if (atomic_cmpxchg(&stopping_cpu, -1, this_cpu) != -1) return; /* For kexec, ensure that offline CPUs are out of MWAIT and in HLT */ @@ -190,7 +191,7 @@ static void native_stop_other_cpus(int wait) * NMIs. */ cpumask_copy(&cpus_stop_mask, cpu_online_mask); - cpumask_clear_cpu(cpu, &cpus_stop_mask); + cpumask_clear_cpu(this_cpu, &cpus_stop_mask); if (!cpumask_empty(&cpus_stop_mask)) { apic_send_IPI_allbutself(REBOOT_VECTOR); @@ -234,6 +235,8 @@ static void native_stop_other_cpus(int wait) * CPUs to stop. */ if (!smp_no_nmi_ipi && !register_stop_handler()) { + unsigned int cpu; + pr_emerg("Shutting down cpus with NMI\n"); for_each_cpu(cpu, &cpus_stop_mask) |