linux-kernel - [PATCH] cpu/hotplug: Abort disabling secondary CPUs if wakeup is pending

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Date:   Mon,  3 Jun 2019 10:01:03 +0530
From:   Pavankumar Kondeti <pkondeti@...eaurora.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        iri Kosina <jkosina@...e.cz>,
        Mukesh Ojha <mojha@...eaurora.org>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Pavankumar Kondeti <pkondeti@...eaurora.org>
Subject: [PATCH] cpu/hotplug: Abort disabling secondary CPUs if wakeup is pending

When "deep" suspend is enabled, all CPUs except the primary CPU
are hotplugged out. Since CPU hotplug is a costly operation,
check if we have to abort the suspend in between each CPU
hotplug. This would improve the system suspend abort latency
upon detecting a wakeup condition.

Signed-off-by: Pavankumar Kondeti <pkondeti@...eaurora.org>
---
 kernel/cpu.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index f2ef104..784b33d 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1221,6 +1221,13 @@ int freeze_secondary_cpus(int primary)
 	for_each_online_cpu(cpu) {
 		if (cpu == primary)
 			continue;
+
+		if (pm_wakeup_pending()) {
+			pr_info("Aborting disabling non-boot CPUs..\n");
+			error = -EBUSY;
+			break;
+		}
+
 		trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
 		error = _cpu_down(cpu, 1, CPUHP_OFFLINE);
 		trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
-- 
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Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.