linux-kernel - [PATCH v3 32/57] perf: Simplify perf_event_context_sched

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20230612093539.823493926@infradead.org>
Date:   Mon, 12 Jun 2023 11:07:45 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     torvalds@...ux-foundation.org, keescook@...omium.org,
        gregkh@...uxfoundation.org, pbonzini@...hat.com
Cc:     masahiroy@...nel.org, nathan@...nel.org, ndesaulniers@...gle.com,
        nicolas@...sle.eu, catalin.marinas@....com, will@...nel.org,
        vkoul@...nel.org, trix@...hat.com, ojeda@...nel.org,
        peterz@...radead.org, mingo@...hat.com, longman@...hat.com,
        boqun.feng@...il.com, dennis@...nel.org, tj@...nel.org,
        cl@...ux.com, acme@...nel.org, mark.rutland@....com,
        alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
        namhyung@...nel.org, irogers@...gle.com, adrian.hunter@...el.com,
        juri.lelli@...hat.com, vincent.guittot@...aro.org,
        dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
        mgorman@...e.de, bristot@...hat.com, vschneid@...hat.com,
        paulmck@...nel.org, frederic@...nel.org, quic_neeraju@...cinc.com,
        joel@...lfernandes.org, josh@...htriplett.org,
        mathieu.desnoyers@...icios.com, jiangshanlai@...il.com,
        rientjes@...gle.com, vbabka@...e.cz, roman.gushchin@...ux.dev,
        42.hyeyoo@...il.com, apw@...onical.com, joe@...ches.com,
        dwaipayanray1@...il.com, lukas.bulwahn@...il.com,
        john.johansen@...onical.com, paul@...l-moore.com,
        jmorris@...ei.org, serge@...lyn.com, linux-kbuild@...r.kernel.org,
        linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org,
        llvm@...ts.linux.dev, linux-perf-users@...r.kernel.org,
        rcu@...r.kernel.org, linux-security-module@...r.kernel.org,
        tglx@...utronix.de, ravi.bangoria@....com, error27@...il.com,
        luc.vanoostenryck@...il.com
Subject: [PATCH v3 32/57] perf: Simplify perf_event_context_sched_in()


Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 kernel/events/core.c |   38 +++++++++++++++-----------------------
 1 file changed, 15 insertions(+), 23 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -713,6 +713,9 @@ static void perf_ctx_enable(struct perf_
 		perf_pmu_enable(pmu_ctx->pmu);
 }
 
+DEFINE_GUARD(perf_ctx_disable, struct perf_event_context *,
+	     perf_ctx_disable(_T), perf_ctx_enable(_T))
+
 static void ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type);
 static void ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type);
 
@@ -3906,31 +3909,27 @@ static void perf_event_context_sched_in(
 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
 	struct perf_event_context *ctx;
 
-	rcu_read_lock();
+	guard(rcu)();
+
 	ctx = rcu_dereference(task->perf_event_ctxp);
 	if (!ctx)
-		goto rcu_unlock;
-
-	if (cpuctx->task_ctx == ctx) {
-		perf_ctx_lock(cpuctx, ctx);
-		perf_ctx_disable(ctx);
-
-		perf_ctx_sched_task_cb(ctx, true);
-
-		perf_ctx_enable(ctx);
-		perf_ctx_unlock(cpuctx, ctx);
-		goto rcu_unlock;
-	}
+		return;
 
-	perf_ctx_lock(cpuctx, ctx);
+	guard(perf_ctx_lock)(cpuctx, ctx);
 	/*
 	 * We must check ctx->nr_events while holding ctx->lock, such
 	 * that we serialize against perf_install_in_context().
 	 */
 	if (!ctx->nr_events)
-		goto unlock;
+		return;
+
+	guard(perf_ctx_disable)(ctx);
+
+	if (cpuctx->task_ctx == ctx) {
+		perf_ctx_sched_task_cb(ctx, true);
+		return;
+	}
 
-	perf_ctx_disable(ctx);
 	/*
 	 * We want to keep the following priority order:
 	 * cpu pinned (that don't need to move), task pinned,
@@ -3950,13 +3949,6 @@ static void perf_event_context_sched_in(
 
 	if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
 		perf_ctx_enable(&cpuctx->ctx);
-
-	perf_ctx_enable(ctx);
-
-unlock:
-	perf_ctx_unlock(cpuctx, ctx);
-rcu_unlock:
-	rcu_read_unlock();
 }
 
 /*