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Mon, 12 Jun 2023 11:38:53 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id C0F5430A77B6E; Mon, 12 Jun 2023 11:38:48 +0200 (CEST) Message-ID: <20230612093540.037803940@infradead.org> User-Agent: quilt/0.66 Date: Mon, 12 Jun 2023 11:07:48 +0200 From: Peter Zijlstra To: torvalds@linux-foundation.org, keescook@chromium.org, gregkh@linuxfoundation.org, pbonzini@redhat.com Cc: masahiroy@kernel.org, nathan@kernel.org, ndesaulniers@google.com, nicolas@fjasle.eu, catalin.marinas@arm.com, will@kernel.org, vkoul@kernel.org, trix@redhat.com, ojeda@kernel.org, peterz@infradead.org, mingo@redhat.com, longman@redhat.com, boqun.feng@gmail.com, dennis@kernel.org, tj@kernel.org, cl@linux.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, namhyung@kernel.org, irogers@google.com, adrian.hunter@intel.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, paulmck@kernel.org, frederic@kernel.org, quic_neeraju@quicinc.com, joel@joelfernandes.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, rientjes@google.com, vbabka@suse.cz, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, apw@canonical.com, joe@perches.com, dwaipayanray1@gmail.com, lukas.bulwahn@gmail.com, john.johansen@canonical.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, llvm@lists.linux.dev, linux-perf-users@vger.kernel.org, rcu@vger.kernel.org, linux-security-module@vger.kernel.org, tglx@linutronix.de, ravi.bangoria@amd.com, error27@gmail.com, luc.vanoostenryck@gmail.com Subject: [PATCH v3 35/57] perf: Simplify *perf_event_read*() References: <20230612090713.652690195@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Signed-off-by: Peter Zijlstra (Intel) --- kernel/events/core.c | 54 ++++++++++++++++----------------------------------- 1 file changed, 17 insertions(+), 37 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4435,7 +4435,8 @@ static void __perf_event_read(void *info if (ctx->task && cpuctx->task_ctx != ctx) return; - raw_spin_lock(&ctx->lock); + guard(raw_spinlock)(&ctx->lock); + if (ctx->is_active & EVENT_TIME) { update_context_time(ctx); update_cgrp_time_from_event(event); @@ -4446,12 +4447,12 @@ static void __perf_event_read(void *info perf_event_update_sibling_time(event); if (event->state != PERF_EVENT_STATE_ACTIVE) - goto unlock; + return; if (!data->group) { pmu->read(event); data->ret = 0; - goto unlock; + return; } pmu->start_txn(pmu, PERF_PMU_TXN_READ); @@ -4469,9 +4470,6 @@ static void __perf_event_read(void *info } data->ret = pmu->commit_txn(pmu); - -unlock: - raw_spin_unlock(&ctx->lock); } static inline u64 perf_event_count(struct perf_event *event) @@ -4502,43 +4500,32 @@ static void calc_timer_values(struct per int perf_event_read_local(struct perf_event *event, u64 *value, u64 *enabled, u64 *running) { - unsigned long flags; - int ret = 0; - /* * Disabling interrupts avoids all counter scheduling (context * switches, timer based rotation and IPIs). */ - local_irq_save(flags); + guard(irqsave)(); /* * It must not be an event with inherit set, we cannot read * all child counters from atomic context. */ - if (event->attr.inherit) { - ret = -EOPNOTSUPP; - goto out; - } + if (event->attr.inherit) + return -EOPNOTSUPP; /* If this is a per-task event, it must be for current */ if ((event->attach_state & PERF_ATTACH_TASK) && - event->hw.target != current) { - ret = -EINVAL; - goto out; - } + event->hw.target != current) + return -EINVAL; /* If this is a per-CPU event, it must be for this CPU */ if (!(event->attach_state & PERF_ATTACH_TASK) && - event->cpu != smp_processor_id()) { - ret = -EINVAL; - goto out; - } + event->cpu != smp_processor_id()) + return -EINVAL; /* If this is a pinned event it must be running on this CPU */ - if (event->attr.pinned && event->oncpu != smp_processor_id()) { - ret = -EBUSY; - goto out; - } + if (event->attr.pinned && event->oncpu != smp_processor_id()) + return -EBUSY; /* * If the event is currently on this CPU, its either a per-task event, @@ -4558,10 +4545,8 @@ int perf_event_read_local(struct perf_ev if (running) *running = __running; } -out: - local_irq_restore(flags); - return ret; + return 0; } static int perf_event_read(struct perf_event *event, bool group) @@ -4595,7 +4580,7 @@ static int perf_event_read(struct perf_e .ret = 0, }; - preempt_disable(); + guard(preempt)(); event_cpu = __perf_event_read_cpu(event, event_cpu); /* @@ -4609,19 +4594,15 @@ static int perf_event_read(struct perf_e * after this. */ (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1); - preempt_enable(); ret = data.ret; } else if (state == PERF_EVENT_STATE_INACTIVE) { struct perf_event_context *ctx = event->ctx; - unsigned long flags; - raw_spin_lock_irqsave(&ctx->lock, flags); + guard(raw_spinlock_irqsave)(&ctx->lock); state = event->state; - if (state != PERF_EVENT_STATE_INACTIVE) { - raw_spin_unlock_irqrestore(&ctx->lock, flags); + if (state != PERF_EVENT_STATE_INACTIVE) goto again; - } /* * May read while context is not active (e.g., thread is @@ -4635,7 +4616,6 @@ static int perf_event_read(struct perf_e perf_event_update_time(event); if (group) perf_event_update_sibling_time(event); - raw_spin_unlock_irqrestore(&ctx->lock, flags); } return ret;