From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chen Yu Subject: [PATCH][RFC v4] timekeeping: ignore the bogus sleep time if pm_trace is enabled Date: Thu, 18 Aug 2016 18:43:39 +0800 Message-ID: <1471517019-15216-1-git-send-email-yu.c.chen@intel.com> Return-path: Received: from mga11.intel.com ([192.55.52.93]:5785 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751442AbcHRKgs (ORCPT ); Thu, 18 Aug 2016 06:36:48 -0400 Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: linux-pm@vger.kernel.org Cc: Ingo Molnar , "H . Peter Anvin" , x86@kernel.org, Chen Yu , "Rafael J . Wysocki" , John Stultz , Thomas Gleixner , Xunlei Pang , Zhang Rui , linux-kernel@vger.kernel.org Previously we encountered some memory overflow issues due to the bogus sleep time brought by inconsistent rtc, which is triggered when pm_trace is enabled, please refer to: https://patchwork.kernel.org/patch/9286365/ It's improper in the first place to call __timekeeping_inject_sleeptime() in case that pm_trace is enabled simply because that "hash" time value will wreckage the timekeeping subsystem. So this patch ignores the sleep time if pm_trace is enabled in the following situation: 1. rtc is used as persist clock to compensate for sleep time, (because system does not have a nonstop clocksource) or 2. rtc is used to calculate the sleep time in rtc_resume. Cc: Rafael J. Wysocki Cc: John Stultz Cc: Thomas Gleixner Cc: Xunlei Pang Cc: Zhang Rui Cc: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org Suggested-by: Rafael J. Wysocki Reported-by: Janek Kozicki Signed-off-by: Chen Yu --- arch/x86/kernel/rtc.c | 7 +++++++ kernel/time/timekeeping.c | 14 +++++++++++++- 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c index 79c6311c..6039138 100644 --- a/arch/x86/kernel/rtc.c +++ b/arch/x86/kernel/rtc.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include @@ -146,6 +147,12 @@ void read_persistent_clock(struct timespec *ts) x86_platform.get_wallclock(ts); } +bool persistent_clock_is_usable(void) +{ + /* Unusable if pm_trace is enabled. */ + return !((x86_platform.get_wallclock == mach_get_cmos_time) && + pm_trace_is_enabled()); +} static struct resource rtc_resources[] = { [0] = { diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 3b65746..3122bd2b 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -23,6 +23,7 @@ #include #include #include +#include #include "tick-internal.h" #include "ntp_internal.h" @@ -1450,6 +1451,11 @@ void __weak read_boot_clock64(struct timespec64 *ts) ts->tv_nsec = 0; } +bool __weak persistent_clock_is_usable(void) +{ + return true; +} + /* Flag for if timekeeping_resume() has injected sleeptime */ static bool sleeptime_injected; @@ -1551,7 +1557,7 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk, */ bool timekeeping_rtc_skipresume(void) { - return sleeptime_injected; + return sleeptime_injected || pm_trace_is_enabled(); } /** @@ -1662,6 +1668,12 @@ void timekeeping_resume(void) } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) { ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time); sleeptime_injected = true; + /* + * If rtc is used as persist clock thus it + * would be bogus when pm_trace is enabled. + */ + if (!persistent_clock_is_usable()) + sleeptime_injected = false; } if (sleeptime_injected) -- 2.7.4