From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Greg KH <gregkh@linuxfoundation.org>,
torvalds@linux-foundation.org, akpm@linux-foundation.org,
alan@lxorguk.ukuu.org.uk, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Prarit Bhargava <prarit@redhat.com>,
John Stultz <johnstul@us.ibm.com>
Subject: [ 34/37] timekeeping: Provide hrtimer update function
Date: Tue, 17 Jul 2012 17:03:11 -0700 [thread overview]
Message-ID: <20120717232434.254592477@linuxfoundation.org> (raw)
In-Reply-To: <20120717232431.399005532@linuxfoundation.org>
From: Greg KH <gregkh@linuxfoundation.org>
3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thomas Gleixner <tglx@linutronix.de>
This is a backport of f6c06abfb3972ad4914cef57d8348fcb2932bc3b
To finally fix the infamous leap second issue and other race windows
caused by functions which change the offsets between the various time
bases (CLOCK_MONOTONIC, CLOCK_REALTIME and CLOCK_BOOTTIME) we need a
function which atomically gets the current monotonic time and updates
the offsets of CLOCK_REALTIME and CLOCK_BOOTTIME with minimalistic
overhead. The previous patch which provides ktime_t offsets allows us
to make this function almost as cheap as ktime_get() which is going to
be replaced in hrtimer_interrupt().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Link: http://lkml.kernel.org/r/1341960205-56738-7-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/hrtimer.h | 1 +
kernel/time/timekeeping.c | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 35 insertions(+)
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -327,6 +327,7 @@ extern ktime_t ktime_get(void);
extern ktime_t ktime_get_real(void);
extern ktime_t ktime_get_boottime(void);
extern ktime_t ktime_get_monotonic_offset(void);
+extern ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot);
DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1273,6 +1273,40 @@ void get_xtime_and_monotonic_and_sleep_o
} while (read_seqretry(&timekeeper.lock, seq));
}
+#ifdef CONFIG_HIGH_RES_TIMERS
+/**
+ * ktime_get_update_offsets - hrtimer helper
+ * @offs_real: pointer to storage for monotonic -> realtime offset
+ * @offs_boot: pointer to storage for monotonic -> boottime offset
+ *
+ * Returns current monotonic time and updates the offsets
+ * Called from hrtimer_interupt() or retrigger_next_event()
+ */
+ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot)
+{
+ ktime_t now;
+ unsigned int seq;
+ u64 secs, nsecs;
+
+ do {
+ seq = read_seqbegin(&timekeeper.lock);
+
+ secs = timekeeper.xtime.tv_sec;
+ nsecs = timekeeper.xtime.tv_nsec;
+ nsecs += timekeeping_get_ns();
+ /* If arch requires, add in gettimeoffset() */
+ nsecs += arch_gettimeoffset();
+
+ *offs_real = timekeeper.offs_real;
+ *offs_boot = timekeeper.offs_boot;
+ } while (read_seqretry(&timekeeper.lock, seq));
+
+ now = ktime_add_ns(ktime_set(secs, 0), nsecs);
+ now = ktime_sub(now, *offs_real);
+ return now;
+}
+#endif
+
/**
* ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format
*/
next prev parent reply other threads:[~2012-07-18 0:07 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-17 23:24 [ 00/23] 3.0.38-stable review Greg KH
2012-07-18 0:02 ` [ 01/37] Remove easily user-triggerable BUG from generic_setlease Greg Kroah-Hartman
2012-07-18 0:02 ` [ 02/37] media: cx231xx: dont DMA to random addresses Greg Kroah-Hartman
2012-07-18 0:02 ` [ 03/37] hwmon: (it87) Preserve configuration register bits on init Greg Kroah-Hartman
2012-07-18 0:02 ` [ 04/37] block: fix infinite loop in __getblk_slow Greg Kroah-Hartman
2012-07-18 0:02 ` [ 05/37] media: dvb-core: Release semaphore on error path dvb_register_device() Greg Kroah-Hartman
2012-07-18 0:02 ` [ 06/37] mtd: nandsim: dont open code a do_div helper Greg Kroah-Hartman
2012-07-18 0:02 ` [ 07/37] md/raid1: fix use-after-free bug in RAID1 data-check code Greg Kroah-Hartman
2012-07-18 0:02 ` [ 08/37] ARM: SAMSUNG: fix race in s3c_adc_start for ADC Greg Kroah-Hartman
2012-07-18 0:02 ` [ 09/37] ACPICA: Fix possible fault in return package object repair code Greg Kroah-Hartman
2012-07-18 0:02 ` [ 10/37] cpufreq / ACPI: Fix not loading acpi-cpufreq driver regression Greg Kroah-Hartman
2012-07-18 0:02 ` [ 11/37] sched/nohz: Rewrite and fix load-avg computation -- again Greg Kroah-Hartman
2012-07-18 0:16 ` Jonathan Nieder
2012-07-20 17:04 ` Peter Zijlstra
2012-07-20 17:13 ` Jonathan Nieder
2012-07-20 17:25 ` Peter Zijlstra
2012-07-21 16:02 ` Doug Smythies
2012-07-18 0:02 ` [ 12/37] intel_ips: blacklist HP ProBook laptops Greg Kroah-Hartman
2012-07-18 0:02 ` [ 13/37] fifo: Do not restart open() if it already found a partner Greg Kroah-Hartman
2012-07-18 0:02 ` [ 14/37] rt2x00usb: fix indexes ordering on RX queue kick Greg Kroah-Hartman
2012-07-18 0:02 ` [ 15/37] e1000e: Correct link check logic for 82571 serdes Greg Kroah-Hartman
2012-07-18 0:02 ` [ 16/37] iwlegacy: always monitor for stuck queues Greg Kroah-Hartman
2012-07-18 0:02 ` [ 17/37] iwlegacy: dont mess up the SCD when removing a key Greg Kroah-Hartman
2012-07-18 0:02 ` [ 18/37] rpmsg: fix dependency on initialization order Greg Kroah-Hartman
2012-07-18 0:02 ` [ 19/37] mac80211: destroy assoc_data correctly if assoc fails Greg Kroah-Hartman
2012-07-18 0:02 ` [ 20/37] stmmac: Fix for nfs hang on multiple reboot Greg Kroah-Hartman
2012-07-18 0:02 ` [ 21/37] bonding: debugfs and network namespaces are incompatible Greg Kroah-Hartman
2012-07-18 0:02 ` [ 22/37] bonding: Manage /proc/net/bonding/ entries from the netdev events Greg Kroah-Hartman
2012-07-18 0:03 ` [ 23/37] Input: bcm5974 - Add support for 2012 MacBook Pro Retina Greg Kroah-Hartman
2012-07-18 0:03 ` [ 24/37] Input: xpad - handle all variations of Mad Catz Beat Pad Greg Kroah-Hartman
2012-07-18 0:03 ` [ 25/37] Input: xpad - add signature for Razer Onza Tournament Edition Greg Kroah-Hartman
2012-07-18 0:03 ` [ 26/37] Input: xpad - add Andamiro Pump It Up pad Greg Kroah-Hartman
2012-07-18 0:03 ` [ 27/37] HID: add support for 2012 MacBook Pro Retina Greg Kroah-Hartman
2012-07-18 0:03 ` [ 28/37] clk: Check parent for NULL in clk_change_rate Greg Kroah-Hartman
2012-07-18 0:03 ` [ 29/37] cfg80211: check iface combinations only when iface is running Greg Kroah-Hartman
2012-07-18 0:03 ` [ 30/37] hrtimer: Provide clock_was_set_delayed() Greg Kroah-Hartman
2012-07-18 0:03 ` [ 31/37] timekeeping: Fix leapsecond triggered load spike issue Greg Kroah-Hartman
2012-07-18 0:03 ` [ 32/37] timekeeping: Maintain ktime_t based offsets for hrtimers Greg Kroah-Hartman
2012-07-18 0:03 ` [ 33/37] hrtimers: Move lock held region in hrtimer_interrupt() Greg Kroah-Hartman
2012-07-18 0:03 ` Greg Kroah-Hartman [this message]
2012-07-18 0:03 ` [ 35/37] hrtimer: Update hrtimer base offsets each hrtimer_interrupt Greg Kroah-Hartman
2012-07-18 0:03 ` [ 37/37] NFC: Export nfc.h to userland Greg Kroah-Hartman
2012-07-18 0:14 ` [ 01/37] Remove easily user-triggerable BUG from generic_setlease Greg KH
2012-07-18 13:36 ` Nick Bowler
2012-07-18 17:58 ` formail doing weird things (was: [ 01/37] Remove easily user-triggerable BUG from generic_setlease) Roland Eggner
2012-07-18 0:11 ` [ 01/23] hwmon: (it87) Preserve configuration register bits on init Greg Kroah-Hartman
2012-07-18 0:11 ` [ 02/23] block: fix infinite loop in __getblk_slow Greg Kroah-Hartman
2012-07-18 0:11 ` [ 03/23] media: dvb-core: Release semaphore on error path dvb_register_device() Greg Kroah-Hartman
2012-07-18 0:11 ` [ 04/23] mtd: nandsim: dont open code a do_div helper Greg Kroah-Hartman
2012-07-18 0:11 ` [ 05/23] ARM: SAMSUNG: fix race in s3c_adc_start for ADC Greg Kroah-Hartman
2012-07-18 0:11 ` [ 06/23] intel_ips: blacklist HP ProBook laptops Greg Kroah-Hartman
2012-07-18 0:12 ` [ 07/23] fifo: Do not restart open() if it already found a partner Greg Kroah-Hartman
2012-07-18 0:12 ` [ 08/23] rt2x00usb: fix indexes ordering on RX queue kick Greg Kroah-Hartman
2012-07-18 0:12 ` [ 09/23] e1000e: Correct link check logic for 82571 serdes Greg Kroah-Hartman
2012-07-18 0:12 ` [ 10/23] Input: xpad - add Andamiro Pump It Up pad Greg Kroah-Hartman
2012-07-18 0:12 ` [ 11/23] tcp: drop SYN+FIN messages Greg Kroah-Hartman
2012-07-18 0:12 ` [ 12/23] cfg80211: check iface combinations only when iface is running Greg Kroah-Hartman
2012-07-18 0:12 ` [ 13/23] ntp: Fix leap-second hrtimer livelock Greg Kroah-Hartman
2012-07-18 0:12 ` [ 14/23] ntp: Correct TAI offset during leap second Greg Kroah-Hartman
2012-07-18 0:12 ` [ 15/23] timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecond Greg Kroah-Hartman
2012-07-18 0:12 ` [ 16/23] time: Move common updates to a function Greg Kroah-Hartman
2012-07-18 0:12 ` [ 17/23] hrtimer: Provide clock_was_set_delayed() Greg Kroah-Hartman
2012-07-18 0:12 ` [ 18/23] timekeeping: Fix leapsecond triggered load spike issue Greg Kroah-Hartman
2012-07-18 0:12 ` [ 19/23] timekeeping: Maintain ktime_t based offsets for hrtimers Greg Kroah-Hartman
2012-07-18 0:12 ` [ 20/23] hrtimers: Move lock held region in hrtimer_interrupt() Greg Kroah-Hartman
2012-07-18 0:12 ` [ 21/23] timekeeping: Provide hrtimer update function Greg Kroah-Hartman
2012-07-18 0:12 ` [ 22/23] hrtimer: Update hrtimer base offsets each hrtimer_interrupt Greg Kroah-Hartman
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