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  1. 04 7月, 2006 2 次提交
  3. 28 6月, 2006 2 次提交
  5. 27 6月, 2006 6 次提交
  7. 26 6月, 2006 1 次提交
  9. 23 6月, 2006 2 次提交
    • P
      [PATCH] When CONFIG_BASE_SMALL=1, cascade() may enter an infinite loop · 3439dd86
      由 Porpoise 提交于 
      When CONFIG_BASE_SAMLL=1, cascade() in may enter the infinite loop.
Because of CONFIG_BASE_SMALL=1(TVR_BITS=6 and TVN_BITS=4), the list
base->tv5 may cascade into base->tv5.  So, the kernel enters the infinite
loop in the function cascade().

I created a test module to verify this bug, and a patch to fix it.

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/timer.h>
#if 0
#include <linux/kdb.h>
#else
#define kdb_printf printk
#endif

#define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
#define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
#define TVN_SIZE (1 << TVN_BITS)
#define TVR_SIZE (1 << TVR_BITS)
#define TVN_MASK (TVN_SIZE - 1)
#define TVR_MASK (TVR_SIZE - 1)

#define TV_SIZE(N)  (N*TVN_BITS  + TVR_BITS)

struct timer_list timer0;
struct timer_list dummy_timer1;
struct timer_list dummy_timer2;

void dummy_timer_fun(unsigned long data) {
}
unsigned long j=0;
void check_timer_base(unsigned long data)
{
        kdb_printf("check_timer_base %08x\n",jiffies);
        mod_timer(&timer0,(jiffies & (~0xFFF)) + 0x1FFF);
}

int init_module(void)
{
        init_timer(&timer0);
        timer0.data = (unsigned long)0;
        timer0.function = check_timer_base;
        mod_timer(&timer0,jiffies+1);

        init_timer(&dummy_timer1);
        dummy_timer1.data = (unsigned long)0;
        dummy_timer1.function = dummy_timer_fun;

        init_timer(&dummy_timer2);
        dummy_timer2.data = (unsigned long)0;
        dummy_timer2.function = dummy_timer_fun;

        j=jiffies;
        j&=(~((1<<TV_SIZE(3))-1));
        j+=(1<<TV_SIZE(3));
        j+=(1<<TV_SIZE(4));

        kdb_printf("mod_timer %08x\n",j);

        mod_timer(&dummy_timer1, j );
        mod_timer(&dummy_timer2, j );

        return 0;
}

void cleanup_module()
{
        del_timer_sync(&timer0);
        del_timer_sync(&dummy_timer1);
        del_timer_sync(&dummy_timer2);
}

(Cleanups from Oleg)

[oleg@tv-sign.ru: use list_replace_init()]
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      3439dd86
    • O
      [PATCH] list: use list_replace_init() instead of list_splice_init() · 626ab0e6
      由 Oleg Nesterov 提交于 
      list_splice_init(list, head) does unneeded job if it is known that
list_empty(head) == 1.  We can use list_replace_init() instead.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      626ab0e6
  11. 22 5月, 2006 1 次提交
    • Z
      [PATCH] Fix a NO_IDLE_HZ timer bug · 0662b713
      由 Zachary Amsden 提交于 
      Under certain timing conditions, a race during boot occurs where timer
ticks are being processed on remote CPUs.  The remote timer ticks can
increment jiffies, and if this happens during a window when a timeout is
very close to expiring but a local tick has not yet been delivered, you can
end up with

1) No softirq pending
2) A local timer wheel which is not synced to jiffies
3) No high resolution timer active
4) A local timer which is supposed to fire before the current jiffies value.

In this circumstance, the comparison in next_timer_interrupt overflows,
because the base of the comparison for high resolution timers is jiffies,
but for the softirq timer wheel, it is relative the the current base of the
wheel (jiffies_base).
Signed-off-by: NZachary Amsden <zach@vmware.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      0662b713
  13. 26 4月, 2006 2 次提交
  15. 11 4月, 2006 1 次提交
    • A
      [PATCH] timer initialisation fix · ba6edfcd
      由 Andrew Morton 提交于 
      We need the boot CPU's tvec_bases[] entry to be initialised super-early in
boot, for early_serial_setup().  That runs within setup_arch(), before even
per-cpu areas are initialised.

The patch changes tvec_bases to use compile-time initialisation, and adds a
separate array `tvec_base_done' to keep track of which CPU has had its
tvec_bases[] entry initialised (because we can no longer use the zeroness of
that tvec_bases[] entry to determine whether it has been initialised).

Thanks to Eugene Surovegin <ebs@ebshome.net> for diagnosing this.

Cc: Eugene Surovegin <ebs@ebshome.net>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      ba6edfcd
  17. 10 4月, 2006 1 次提交
    • J
      [PATCH] x86_64: Fix drift with HPET timer enabled · b20367a6
      由 Jordan Hargrave 提交于 
      If the HPET timer is enabled, the clock can drift by ~3 seconds a day.
This is due to the HPET timer not being initialized with the correct
setting (still using PIT count).

If HZ changes, this drift can become even more pronounced.

HPET patch initializes tick_nsec with correct tick_nsec settings for
HPET timer.

Vojtech comments:

  "It's not entirely correct (it assumes the HPET ticks totally
   exactly), but it's significantly better than assuming the PIT error
   there."
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      b20367a6
  19. 02 4月, 2006 1 次提交
  21. 01 4月, 2006 3 次提交
  23. 26 3月, 2006 2 次提交
    • R
      [PATCH] remove pps support · 5ddcfa87
      由 Roman Zippel 提交于 
      This removes the support for pps.  It's completely unused within the kernel
and is basically in the way for further cleanups.  It should be easier to
readd proper support for it after the rest has been converted to NTP4
(where the pps mechanisms are quite different from NTP3 anyway).
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Cc: Adrian Bunk <bunk@stusta.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      5ddcfa87
    • T
      [PATCH] sys_alarm() unsigned signed conversion fixup · c08b8a49
      由 Thomas Gleixner 提交于 
      alarm() calls the kernel with an unsigend int timeout in seconds.  The
value is stored in the tv_sec field of a struct timeval to setup the
itimer.  The tv_sec field of struct timeval is of type long, which causes
the tv_sec value to be negative on 32 bit machines if seconds > INT_MAX.

Before the hrtimer merge (pre 2.6.16) such a negative value was converted
to the maximum jiffies timeout by the timeval_to_jiffies conversion.  It's
not clear whether this was intended or just happened to be done by the
timeval_to_jiffies code.

hrtimers expect a timeval in canonical form and treat a negative timeout as
already expired.  This breaks the legitimate usage of alarm() with a
timeout value > INT_MAX seconds.

For 32 bit machines it is therefor necessary to limit the internal seconds
value to avoid API breakage.  Instead of doing this in all implementations
of sys_alarm the duplicated sys_alarm code is moved into a common function
in itimer.c
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      c08b8a49
  25. 24 3月, 2006 2 次提交
  27. 17 3月, 2006 1 次提交
  29. 07 3月, 2006 2 次提交
  31. 03 3月, 2006 1 次提交
  33. 18 2月, 2006 1 次提交
    • P
      [PATCH] Provide an interface for getting the current tick length · 726c14bf
      由 Paul Mackerras 提交于 
      This provides an interface for arch code to find out how many
nanoseconds are going to be added on to xtime by the next call to
do_timer.  The value returned is a fixed-point number in 52.12 format
in nanoseconds.  The reason for this format is that it gives the
full precision that the timekeeping code is using internally.

The motivation for this is to fix a problem that has arisen on 32-bit
powerpc in that the value returned by do_gettimeofday drifts apart
from xtime if NTP is being used.  PowerPC is now using a lockless
do_gettimeofday based on reading the timebase register and performing
some simple arithmetic.  (This method of getting the time is also
exported to userspace via the VDSO.)  However, the factor and offset
it uses were calculated based on the nominal tick length and weren't
being adjusted when NTP varied the tick length.

Note that 64-bit powerpc has had the lockless do_gettimeofday for a
long time now.  It also had an extremely hairy routine that got called
from the 32-bit compat routine for adjtimex, which adjusted the
factor and offset according to what it thought the timekeeping code
was going to do.  Not only was this only called if a 32-bit task did
adjtimex (i.e. not if a 64-bit task did adjtimex), it was also
duplicating computations from kernel/timer.c and it wasn't clear that
it was (still) correct.

The simple solution is to ask the timekeeping code how long the
current jiffy will be on each timer interrupt, after calling
do_timer.  If this jiffy will be a different length from the last one,
we then need to compute new values for the factor and offset used in
the lockless do_gettimeofday.  In this way we can keep xtime and
do_gettimeofday in sync, even when NTP is varying the tick length.

Note that when adjtimex varies the tick length, it almost always
introduces the variation from the next tick on.  The only case I could
see where adjtimex would vary the length of the current tick is when
an old-style adjtime adjustment is being cancelled.  (It's not clear
to me why the adjustment has to be cancelled immediately rather than
from the next tick on.)  Thus I don't see any real need for a hook in
adjtimex; the rare case of an old-style adjustment being cancelled can
be fixed up at the next tick.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Acked-by: Njohn stultz <johnstul@us.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      726c14bf
  35. 08 2月, 2006 1 次提交
  37. 11 1月, 2006 2 次提交
  39. 09 1月, 2006 1 次提交
  41. 31 10月, 2005 5 次提交