linux-kernel - [tip: sched/core] arm64, riscv, perf: Remove RCU

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Date:   Fri, 13 Jan 2023 12:31:05 -0000
From:   "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Tony Lindgren <tony@...mide.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Frederic Weisbecker <frederic@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: sched/core] arm64, riscv, perf: Remove RCU_NONIDLE() usage

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     1c38b0615f84f622cd6c821aa40be60fc7f7a096
Gitweb:        https://git.kernel.org/tip/1c38b0615f84f622cd6c821aa40be60fc7f7a096
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Thu, 12 Jan 2023 20:44:00 +01:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Fri, 13 Jan 2023 11:48:17 +01:00

arm64, riscv, perf: Remove RCU_NONIDLE() usage

The PM notifiers should no longer be ran with RCU disabled (per the
previous patches), as such this hack is no longer required either.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Tested-by: Tony Lindgren <tony@...mide.com>
Tested-by: Ulf Hansson <ulf.hansson@...aro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Acked-by: Frederic Weisbecker <frederic@...nel.org>
Link: https://lore.kernel.org/r/20230112195542.151174682@infradead.org
---
 drivers/perf/arm_pmu.c       | 11 +----------
 drivers/perf/riscv_pmu_sbi.c |  8 +-------
 2 files changed, 2 insertions(+), 17 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 9b593f9..c34d5fe 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -758,17 +758,8 @@ static void cpu_pm_pmu_setup(struct arm_pmu *armpmu, unsigned long cmd)
 		case CPU_PM_ENTER_FAILED:
 			 /*
 			  * Restore and enable the counter.
-			  * armpmu_start() indirectly calls
-			  *
-			  * perf_event_update_userpage()
-			  *
-			  * that requires RCU read locking to be functional,
-			  * wrap the call within RCU_NONIDLE to make the
-			  * RCU subsystem aware this cpu is not idle from
-			  * an RCU perspective for the armpmu_start() call
-			  * duration.
 			  */
-			RCU_NONIDLE(armpmu_start(event, PERF_EF_RELOAD));
+			armpmu_start(event, PERF_EF_RELOAD);
 			break;
 		default:
 			break;
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index f6507ef..7b2288d 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -771,14 +771,8 @@ static int riscv_pm_pmu_notify(struct notifier_block *b, unsigned long cmd,
 		case CPU_PM_ENTER_FAILED:
 			/*
 			 * Restore and enable the counter.
-			 *
-			 * Requires RCU read locking to be functional,
-			 * wrap the call within RCU_NONIDLE to make the
-			 * RCU subsystem aware this cpu is not idle from
-			 * an RCU perspective for the riscv_pmu_start() call
-			 * duration.
 			 */
-			RCU_NONIDLE(riscv_pmu_start(event, PERF_EF_RELOAD));
+			riscv_pmu_start(event, PERF_EF_RELOAD);
 			break;
 		default:
 			break;