linux-kernel - [RESEND PATCH v2 2/2] power/idle: enhance the precision of sleep

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: <1466154816-17900-2-git-send-email-zhaoyang.huang@spreadtrum.com>
Date:	Fri, 17 Jun 2016 17:13:36 +0800
From:	Zhaoyang Huang <zhaoyang.huang@...aro.org>
To:	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	mingo@...hat.com, peterz@...radead.org,
	zhaoyang.huang@...eadtrum.com, tglx@...utronix.de
Subject: [RESEND PATCH v2 2/2] power/idle: enhance the precision of sleep_length

There should be a gap between tick_nohz_idle_enter and
tick_nohz_get_sleep_length when idle, which will cause the
sleep_length is not very precised. Change it in this patch.

Signed-off-by: Zhaoyang Huang <zhaoyang.huang@...eadtrum.com>
---
 kernel/time/tick-sched.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 536ada8..ee3be3d 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -975,6 +975,11 @@ void tick_nohz_irq_exit(void)
 ktime_t tick_nohz_get_sleep_length(void)
 {
 	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
+	ktime_t now;
+
+	now = ktime_get();
+	ts->sleep_length = ktime_sub(dev->next_event, now);
 
 	return ts->sleep_length;
 }
-- 
1.7.9.5