diff options
| author | Thomas Gleixner | 2019-07-22 20:47:26 +0200 |
|---|---|---|
| committer | Thomas Gleixner | 2019-07-25 16:12:01 +0200 |
| commit | 832df3d47badcbc860aef617105b6bc1c9459304 (patch) | |
| tree | 72b54a401a69556ad3b226b8e53d2e7611b3a363 /arch/x86/kernel/apic | |
| parent | d0a7166bc7ac4feac5c482ebe8b2417aa3302ef4 (diff) | |
x86/smp: Enhance native_send_call_func_ipi()
Nadav noticed that the cpumask allocations in native_send_call_func_ipi()
are noticeable in microbenchmarks.
Use the new cpumask_or_equal() function to simplify the decision whether
the supplied target CPU mask is either equal to cpu_online_mask or equal to
cpu_online_mask except for the CPU on which the function is invoked.
cpumask_or_equal() or's the target mask and the cpumask of the current CPU
together and compares it to cpu_online_mask.
If the result is false, use the mask based IPI function, otherwise check
whether the current CPU is set in the target mask and invoke either the
send_IPI_all() or the send_IPI_allbutselt() APIC callback.
Make the shorthand decision also depend on the static key which enables
shorthand mode. That allows to remove the extra cpumask comparison with
cpu_callout_mask.
Reported-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105220.768238809@linutronix.de
Diffstat (limited to 'arch/x86/kernel/apic')
| -rw-r--r-- | arch/x86/kernel/apic/ipi.c | 24 |
1 files changed, 11 insertions, 13 deletions
diff --git a/arch/x86/kernel/apic/ipi.c b/arch/x86/kernel/apic/ipi.c index eaac65bf58f0..117ee2323f59 100644 --- a/arch/x86/kernel/apic/ipi.c +++ b/arch/x86/kernel/apic/ipi.c @@ -83,23 +83,21 @@ void native_send_call_func_single_ipi(int cpu) void native_send_call_func_ipi(const struct cpumask *mask) { - cpumask_var_t allbutself; + if (static_branch_likely(&apic_use_ipi_shorthand)) { + unsigned int cpu = smp_processor_id(); - if (!alloc_cpumask_var(&allbutself, GFP_ATOMIC)) { - apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR); + if (!cpumask_or_equal(mask, cpumask_of(cpu), cpu_online_mask)) + goto sendmask; + + if (cpumask_test_cpu(cpu, mask)) + apic->send_IPI_all(CALL_FUNCTION_VECTOR); + else if (num_online_cpus() > 1) + apic->send_IPI_allbutself(CALL_FUNCTION_VECTOR); return; } - cpumask_copy(allbutself, cpu_online_mask); - __cpumask_clear_cpu(smp_processor_id(), allbutself); - - if (cpumask_equal(mask, allbutself) && - cpumask_equal(cpu_online_mask, cpu_callout_mask)) - apic->send_IPI_allbutself(CALL_FUNCTION_VECTOR); - else - apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR); - - free_cpumask_var(allbutself); +sendmask: + apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR); } #endif /* CONFIG_SMP */ |