diff options
Diffstat (limited to 'arch/powerpc/include/asm/paravirt.h')
| -rw-r--r-- | arch/powerpc/include/asm/paravirt.h | 47 |
1 files changed, 44 insertions, 3 deletions
diff --git a/arch/powerpc/include/asm/paravirt.h b/arch/powerpc/include/asm/paravirt.h index e08513d73119..ac4279208d63 100644 --- a/arch/powerpc/include/asm/paravirt.h +++ b/arch/powerpc/include/asm/paravirt.h @@ -71,6 +71,11 @@ static inline void yield_to_any(void) { plpar_hcall_norets_notrace(H_CONFER, -1, 0); } + +static inline bool is_vcpu_idle(int vcpu) +{ + return lppaca_of(vcpu).idle; +} #else static inline bool is_shared_processor(void) { @@ -100,6 +105,10 @@ static inline void prod_cpu(int cpu) ___bad_prod_cpu(); /* This would be a bug */ } +static inline bool is_vcpu_idle(int vcpu) +{ + return false; +} #endif #define vcpu_is_preempted vcpu_is_preempted @@ -121,9 +130,23 @@ static inline bool vcpu_is_preempted(int cpu) if (!is_shared_processor()) return false; + /* + * If the hypervisor has dispatched the target CPU on a physical + * processor, then the target CPU is definitely not preempted. + */ + if (!(yield_count_of(cpu) & 1)) + return false; + + /* + * If the target CPU has yielded to Hypervisor but OS has not + * requested idle then the target CPU is definitely preempted. + */ + if (!is_vcpu_idle(cpu)) + return true; + #ifdef CONFIG_PPC_SPLPAR if (!is_kvm_guest()) { - int first_cpu; + int first_cpu, i; /* * The result of vcpu_is_preempted() is used in a @@ -149,11 +172,29 @@ static inline bool vcpu_is_preempted(int cpu) */ if (cpu_first_thread_sibling(cpu) == first_cpu) return false; + + /* + * If any of the threads of the target CPU's core are not + * preempted or ceded, then consider target CPU to be + * non-preempted. + */ + first_cpu = cpu_first_thread_sibling(cpu); + for (i = first_cpu; i < first_cpu + threads_per_core; i++) { + if (i == cpu) + continue; + if (!(yield_count_of(i) & 1)) + return false; + if (!is_vcpu_idle(i)) + return true; + } } #endif - if (yield_count_of(cpu) & 1) - return true; + /* + * None of the threads in target CPU's core are running but none of + * them were preempted too. Hence assume the target CPU to be + * non-preempted. + */ return false; } |