Messages in this thread Patch in this message | | | Date | Wed, 28 May 2008 19:15:41 +0100 (BST) | From | "Maciej W. Rozycki" <> | Subject | [PATCH] NTP: Let update_persistent_clock() sleep |
| |
This is a change that makes the 11-minute RTC update be run in the process context. This is so that update_persistent_clock() can sleep, which may be required for certain types of RTC hardware -- most notably I2C devices.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> --- Hello,
After the initial enthusiasm, I am not sure how my series of patches to let read_persistent_clock() and update_persistent_clock() use the class RTC subsystem is going to be handled. As keeping the order of patches is required to avoid breakage in various places, I will try to coordinate the changes and submit them one by one as the dependencies get satisfied. I hope this is OK and will take less than half a year. ;)
Given this one applies to generic code and is required by all the other changes, while not requiring anything and not meant to break anything, ;) I think this is ready to go. It may be worth testing that moving the function into the process context does not cause any regressions for some obscure configuration.
I am not sure who actually claims maintenance of kernel/time/ntp.c, but it looks, Thomas, you seem to be our current time overseer -- could you please speak out on this change? I'd like this change to get applied somewhere reasonable -- is it -mm?
Maciej
patch-2.6.26-rc1-20080505-sync-cmos-work-0 diff -up --recursive --new-file linux-2.6.26-rc1-20080505.macro/kernel/time/ntp.c linux-2.6.26-rc1-20080505/kernel/time/ntp.c --- linux-2.6.26-rc1-20080505.macro/kernel/time/ntp.c 2008-05-05 02:56:03.000000000 +0000 +++ linux-2.6.26-rc1-20080505/kernel/time/ntp.c 2008-05-05 21:10:50.000000000 +0000 @@ -3,6 +3,8 @@ * * NTP state machine interfaces and logic. * + * Copyright (c) 2008 Maciej W. Rozycki + * * This code was mainly moved from kernel/timer.c and kernel/time.c * Please see those files for relevant copyright info and historical * changelogs. @@ -17,6 +19,7 @@ #include <linux/capability.h> #include <linux/math64.h> #include <linux/clocksource.h> +#include <linux/workqueue.h> #include <asm/timex.h> /* @@ -218,11 +221,13 @@ void second_overflow(void) /* Disable the cmos update - used by virtualization and embedded */ int no_sync_cmos_clock __read_mostly; -static void sync_cmos_clock(unsigned long dummy); +static void sync_cmos_clock(unsigned long data); +static void do_sync_cmos_clock(struct work_struct *work); static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0); +static DECLARE_WORK(sync_cmos_work, do_sync_cmos_clock); -static void sync_cmos_clock(unsigned long dummy) +static void do_sync_cmos_clock(struct work_struct *work) { struct timespec now, next; int fail = 1; @@ -261,6 +266,12 @@ static void sync_cmos_clock(unsigned lon mod_timer(&sync_cmos_timer, jiffies + timespec_to_jiffies(&next)); } +static void sync_cmos_clock(unsigned long data) +{ + /* Some implementations of update_persistent_clock() may sleep. */ + schedule_work(&sync_cmos_work); +} + static void notify_cmos_timer(void) { if (!no_sync_cmos_clock)
| |