On Mon, 12 Dec 2022 12:58:37 +0000, Like Xu <like.xu.linux@xxxxxxxxx> wrote: > > From: Like Xu <likexu@xxxxxxxxxxx> > > Like syscalls users, kernel-space perf_event creators may also use group > counters abstraction to gain pmu functionalities, and an in-kernel counter > groups behave much like normal 'single' counters, following the group > semantics-based behavior. > > No functional changes at this time. An example will be that KVM creates > Intel slot event as group leader and other topdown metric events to emulate > MSR_PERF_METRICS pmu capability for guests. > > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Marc Zyngier <maz@xxxxxxxxxx> > Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx> > Cc: kvmarm@xxxxxxxxxxxxxxx > Cc: linux-perf-users@xxxxxxxxxxxxxxx > Signed-off-by: Like Xu <likexu@xxxxxxxxxxx> > --- > arch/arm64/kvm/pmu-emul.c | 4 ++-- > arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 4 ++-- > arch/x86/kvm/pmu.c | 2 +- > arch/x86/kvm/vmx/pmu_intel.c | 2 +- > include/linux/perf_event.h | 1 + > kernel/events/core.c | 4 +++- > kernel/events/hw_breakpoint.c | 4 ++-- > kernel/events/hw_breakpoint_test.c | 2 +- > kernel/watchdog_hld.c | 2 +- > 9 files changed, 14 insertions(+), 11 deletions(-) > > diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c > index 24908400e190..11c3386bc86b 100644 > --- a/arch/arm64/kvm/pmu-emul.c > +++ b/arch/arm64/kvm/pmu-emul.c > @@ -624,7 +624,7 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc) > > attr.sample_period = compute_period(pmc, kvm_pmu_get_pmc_value(pmc)); > > - event = perf_event_create_kernel_counter(&attr, -1, current, > + event = perf_event_create_kernel_counter(&attr, -1, current, NULL, > kvm_pmu_perf_overflow, pmc); Wouldn't it be better to have a separate helper that takes the group leader as a parameter, and reimplement perf_event_create_kernel_counter() in term of this helper? M. -- Without deviation from the norm, progress is not possible.
