Messages in this thread | | | Date | Thu, 4 Aug 2022 16:49:08 +0800 | Subject | Re: [PATCH v2 2/7] perf/x86/core: Remove unnecessary stubs provided for KVM-only helpers | From | Like Xu <> |
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On 4/8/2022 3:26 am, Sean Christopherson wrote: > Remove CONFIG_PERF_EVENT=n stubs for functions that are effectively > KVM-only. KVM selects PERF_EVENT and will never consume the stubs. > Dropping the unnecessary stubs will allow simplifying x86_perf_get_lbr()
Giggling, I used to have a similar cleanup patch sitting in a corner somewhere.
> by getting rid of the impossible-to-hit error path (which KVM doesn't > even check). > > Opportunstically reorganize the declarations to collapse multiple > CONFIG_PERF_EVENTS #ifdefs. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/include/asm/perf_event.h | 53 ++++++++----------------------- > 1 file changed, 13 insertions(+), 40 deletions(-) > > diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h > index cc47044401ff..aba196172500 100644 > --- a/arch/x86/include/asm/perf_event.h > +++ b/arch/x86/include/asm/perf_event.h > @@ -509,46 +509,18 @@ extern u64 perf_get_hw_event_config(int hw_event); > extern void perf_check_microcode(void); > extern void perf_clear_dirty_counters(void); > extern int x86_perf_rdpmc_index(struct perf_event *event); > -#else > -static inline void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap) > -{ > - memset(cap, 0, sizeof(*cap)); > -} > > -static inline u64 perf_get_hw_event_config(int hw_event) > -{ > - return 0; > -} > - > -static inline void perf_events_lapic_init(void) { } > -static inline void perf_check_microcode(void) { } > -#endif > - > -#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL) > +#ifdef CONFIG_CPU_SUP_INTEL > extern struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr, void *data); > extern int x86_perf_get_lbr(struct x86_pmu_lbr *lbr); > -#else > -struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr, void *data); > -static inline int x86_perf_get_lbr(struct x86_pmu_lbr *lbr) > -{ > - return -1; > -} > -#endif > +extern void intel_pt_handle_vmx(int on); > +#endif /* CONFIG_CPU_SUP_INTEL */ > > -#ifdef CONFIG_CPU_SUP_INTEL > - extern void intel_pt_handle_vmx(int on); > -#else > -static inline void intel_pt_handle_vmx(int on) > -{ > +#ifdef CONFIG_CPU_SUP_AMD > +extern void amd_pmu_enable_virt(void); > +extern void amd_pmu_disable_virt(void); > > -} > -#endif > - > -#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_AMD) > - extern void amd_pmu_enable_virt(void); > - extern void amd_pmu_disable_virt(void); > - > -#if defined(CONFIG_PERF_EVENTS_AMD_BRS) > +#ifdef CONFIG_PERF_EVENTS_AMD_BRS > > #define PERF_NEEDS_LOPWR_CB 1 > > @@ -566,12 +538,13 @@ static inline void perf_lopwr_cb(bool lopwr_in) > static_call_mod(perf_lopwr_cb)(lopwr_in); > } > > -#endif /* PERF_NEEDS_LOPWR_CB */
Oops, now the definition of PERF_NEEDS_LOPWR_CB will not be unset. This is not mentioned in the commit message and may cause trouble.
> +#endif /* CONFIG_PERF_EVENTS_AMD_BRS */ > +#endif /* CONFIG_CPU_SUP_AMD */ > > -#else > - static inline void amd_pmu_enable_virt(void) { } > - static inline void amd_pmu_disable_virt(void) { } > -#endif > +#else /* !CONFIG_PERF_EVENTS */ > +static inline void perf_events_lapic_init(void) { } > +static inline void perf_check_microcode(void) { } > +#endif /* CONFIG_PERF_EVENTS */ > > #define arch_perf_out_copy_user copy_from_user_nmi >
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