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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 EBB5330A77B75; Mon, 12 Jun 2023 11:38:48 +0200 (CEST) Message-ID: <20230612093540.638818161@infradead.org> User-Agent: quilt/0.66 Date: Mon, 12 Jun 2023 11:07:56 +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 43/57] perf: Simplify perf_sw_event() 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 | 37 ++++++++++++------------------------- 1 file changed, 12 insertions(+), 25 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9701,17 +9701,15 @@ static void do_perf_sw_event(enum perf_t struct perf_event *event; struct hlist_head *head; - rcu_read_lock(); + guard(rcu)(); head = find_swevent_head_rcu(swhash, type, event_id); if (!head) - goto end; + return; hlist_for_each_entry_rcu(event, head, hlist_entry) { if (perf_swevent_match(event, type, event_id, data, regs)) perf_swevent_event(event, nr, data, regs); } -end: - rcu_read_unlock(); } DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); @@ -9746,16 +9744,13 @@ void __perf_sw_event(u32 event_id, u64 n { int rctx; - preempt_disable_notrace(); + guard(preempt_notrace)(); rctx = perf_swevent_get_recursion_context(); if (unlikely(rctx < 0)) - goto fail; + return; ___perf_sw_event(event_id, nr, regs, addr); - perf_swevent_put_recursion_context(rctx); -fail: - preempt_enable_notrace(); } static void perf_swevent_read(struct perf_event *event) @@ -9844,21 +9839,17 @@ static int swevent_hlist_get_cpu(int cpu struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); int err = 0; - mutex_lock(&swhash->hlist_mutex); + guard(mutex)(&swhash->hlist_mutex); if (!swevent_hlist_deref(swhash) && cpumask_test_cpu(cpu, perf_online_mask)) { struct swevent_hlist *hlist; hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); - if (!hlist) { - err = -ENOMEM; - goto exit; - } + if (!hlist) + return -ENOMEM; rcu_assign_pointer(swhash->swevent_hlist, hlist); } swhash->hlist_refcount++; -exit: - mutex_unlock(&swhash->hlist_mutex); return err; } @@ -10115,16 +10106,12 @@ void perf_tp_event(u16 event_type, u64 c if (task && task != current) { struct perf_event_context *ctx; - rcu_read_lock(); + guard(rcu)(); ctx = rcu_dereference(task->perf_event_ctxp); - if (!ctx) - goto unlock; - - raw_spin_lock(&ctx->lock); - perf_tp_event_target_task(count, record, regs, &data, ctx); - raw_spin_unlock(&ctx->lock); -unlock: - rcu_read_unlock(); + if (ctx) { + guard(raw_spinlock)(&ctx->lock); + perf_tp_event_target_task(count, record, regs, &data, ctx); + } } perf_swevent_put_recursion_context(rctx);