cpu/hotplug: Abort disabling secondary CPUs if wakeup is pending

When "deep" suspend is enabled, all CPUs except the primary CPU are frozen
via CPU hotplug one by one. After all secondary CPUs are unplugged the
wakeup pending condition is evaluated and if pending the suspend operation
is aborted and the secondary CPUs are brought up again.

CPU hotplug is a slow operation, so it makes sense to check for wakeup
pending in the freezer loop before bringing down the next CPU. This
improves the system suspend abort latency significantly.

[ tglx: Massaged changelog and improved printk message ]

Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: iri Kosina <jkosina@suse.cz>
Cc: Mukesh Ojha <mojha@codeaurora.org>
Cc: linux-pm@vger.kernel.org
Link: https://lkml.kernel.org/r/1559536263-16472-1-git-send-email-pkondeti@codeaurora.org

diff --git a/kernel/cpu.c b/kernel/cpu.c
index be82cbc11a8a070ca3fe5e5c034dc5abc4089da3..0778249cd49da8033420d4c030d9b628b95444b0 100644 (file)
--- 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("Wakeup pending. Abort CPU freeze\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);