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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 322B430A79087; Mon, 12 Jun 2023 11:38:49 +0200 (CEST) Message-ID: <20230612093541.454144142@infradead.org> User-Agent: quilt/0.66 Date: Mon, 12 Jun 2023 11:08:07 +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 54/57] perf: Misc cleanups References: <20230612090713.652690195@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org Signed-off-by: Peter Zijlstra (Intel) --- kernel/events/core.c | 64 +++++++++++++++++++-------------------------------- 1 file changed, 25 insertions(+), 39 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1274,13 +1274,11 @@ perf_event_ctx_lock_nested(struct perf_e struct perf_event_context *ctx; again: - rcu_read_lock(); - ctx = READ_ONCE(event->ctx); - if (!refcount_inc_not_zero(&ctx->refcount)) { - rcu_read_unlock(); - goto again; + scoped_guard (rcu) { + ctx = READ_ONCE(event->ctx); + if (!refcount_inc_not_zero(&ctx->refcount)) + goto again; } - rcu_read_unlock(); mutex_lock_nested(&ctx->mutex, nesting); if (event->ctx != ctx) { @@ -2254,7 +2252,7 @@ event_sched_out(struct perf_event *event */ list_del_init(&event->active_list); - perf_pmu_disable(event->pmu); + guard(perf_pmu_disable)(event->pmu); event->pmu->del(event, 0); event->oncpu = -1; @@ -2288,8 +2286,6 @@ event_sched_out(struct perf_event *event ctx->nr_freq--; if (event->attr.exclusive || !cpc->active_oncpu) cpc->exclusive = 0; - - perf_pmu_enable(event->pmu); } static void @@ -3219,7 +3215,8 @@ static void __pmu_ctx_sched_out(struct p if (!event_type) return; - perf_pmu_disable(pmu); + guard(perf_pmu_disable)(pmu); + if (event_type & EVENT_PINNED) { list_for_each_entry_safe(event, tmp, &pmu_ctx->pinned_active, @@ -3239,7 +3236,6 @@ static void __pmu_ctx_sched_out(struct p */ pmu_ctx->rotate_necessary = 0; } - perf_pmu_enable(pmu); } static void @@ -3586,13 +3582,10 @@ static void __perf_pmu_sched_task(struct if (WARN_ON_ONCE(!pmu->sched_task)) return; - perf_ctx_lock(cpuctx, cpuctx->task_ctx); - perf_pmu_disable(pmu); + guard(perf_ctx_lock)(cpuctx, cpuctx->task_ctx); + guard(perf_pmu_disable)(pmu); pmu->sched_task(cpc->task_epc, sched_in); - - perf_pmu_enable(pmu); - perf_ctx_unlock(cpuctx, cpuctx->task_ctx); } static void perf_pmu_sched_task(struct task_struct *prev, @@ -12655,8 +12648,6 @@ static void __perf_pmu_install_event(str struct perf_event_context *ctx, int cpu, struct perf_event *event) { - struct perf_event_pmu_context *epc; - /* * Now that the events are unused, put their old ctx and grab a * reference on the new context. @@ -12665,8 +12656,7 @@ static void __perf_pmu_install_event(str get_ctx(ctx); event->cpu = cpu; - epc = find_get_pmu_context(pmu, ctx, event); - event->pmu_ctx = epc; + event->pmu_ctx = find_get_pmu_context(pmu, ctx, event); if (event->state >= PERF_EVENT_STATE_OFF) event->state = PERF_EVENT_STATE_INACTIVE; @@ -12815,12 +12805,12 @@ perf_event_exit_event(struct perf_event static void perf_event_exit_task_context(struct task_struct *child) { - struct perf_event_context *child_ctx, *clone_ctx = NULL; + struct perf_event_context *clone_ctx = NULL; struct perf_event *child_event, *next; WARN_ON_ONCE(child != current); - child_ctx = perf_pin_task_context(child); + CLASS(pin_task_ctx, child_ctx)(child); if (!child_ctx) return; @@ -12834,27 +12824,27 @@ static void perf_event_exit_task_context * without ctx::mutex (it cannot because of the move_group double mutex * lock thing). See the comments in perf_install_in_context(). */ - mutex_lock(&child_ctx->mutex); + guard(mutex)(&child_ctx->mutex); /* * In a single ctx::lock section, de-schedule the events and detach the * context from the task such that we cannot ever get it scheduled back * in. */ - raw_spin_lock_irq(&child_ctx->lock); - task_ctx_sched_out(child_ctx, EVENT_ALL); + scoped_guard (raw_spinlock_irq, &child_ctx->lock) { + task_ctx_sched_out(child_ctx, EVENT_ALL); - /* - * Now that the context is inactive, destroy the task <-> ctx relation - * and mark the context dead. - */ - RCU_INIT_POINTER(child->perf_event_ctxp, NULL); - put_ctx(child_ctx); /* cannot be last */ - WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); - put_task_struct(current); /* cannot be last */ + /* + * Now that the context is inactive, destroy the task <-> ctx + * relation and mark the context dead. + */ + RCU_INIT_POINTER(child->perf_event_ctxp, NULL); + put_ctx(child_ctx); /* cannot be last */ + WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); + put_task_struct(current); /* cannot be last */ - clone_ctx = unclone_ctx(child_ctx); - raw_spin_unlock_irq(&child_ctx->lock); + clone_ctx = unclone_ctx(child_ctx); + } if (clone_ctx) put_ctx(clone_ctx); @@ -12868,10 +12858,6 @@ static void perf_event_exit_task_context list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) perf_event_exit_event(child_event, child_ctx); - - mutex_unlock(&child_ctx->mutex); - - put_ctx(child_ctx); } /*