On 12/12/2022 9:23 pm, Marc Zyngier wrote:
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.
Applied. It makes changes more concise, thank you.
