Re: [PATCH *] use 64 bit jiffies

Jörn Engel
2003-02-17T13:45:59Z

On Tue, 4 February 2003 14:04:38 +0100, Tim Schmielau wrote:
>
> A patch for 2.4.20-pre7 (and maybe later) is at
> http://www.physik3.uni-rostock.de/tim/kernel/2.4/

Some of the architectures appear to be untested. This fixes arm and
beautifies m68k.
( At least, I hope so. I didn't test it either :)

Tim, is the inline patch fine with you?

Jörn

--
There's nothing better for promoting creativity in a medium than
making an audience feel "Hmm ­ I could do better than that!"
-- Douglas Adams in a slashdot interview

--- linux-2.4.20-pre7-j64/include/linux/timex.h Thu Nov 22 20:46:18 2001
+++ linux-2.4.20-pre7-j64-dbg/include/linux/timex.h Wed Sep 25 19:11:51 2002
@@ -53,6 +53,13 @@

#include <asm/param.h>

+#ifdef CONFIG_DEBUG_JIFFIESWRAP
+ /* Make the jiffies counter wrap around sooner. */
+# define INITIAL_JIFFIES ((unsigned long)(-300*HZ))
+#else
+# define INITIAL_JIFFIES 0
+#endif
+
/*
* The following defines establish the engineering parameters of the PLL
* model. The HZ variable establishes the timer interrupt frequency, 100 Hz

--- linux-2.4.20-pre7-j64/kernel/timer.c Wed Sep 25 18:38:36 2002
+++ linux-2.4.20-pre7-j64-dbg/kernel/timer.c Wed Sep 25 19:11:51 2002
@@ -65,9 +65,10 @@

extern int do_setitimer(int, struct itimerval *, struct itimerval *);

-unsigned long volatile jiffies;
+unsigned long volatile jiffies = INITIAL_JIFFIES;
#ifdef NEEDS_JIFFIES_64
-static unsigned int volatile jiffies_msb_flips;
+static unsigned int volatile
+ jiffies_msb_flips = INITIAL_JIFFIES>>(BITS_PER_LONG-1);
#endif

unsigned int * prof_buffer;
@@ -123,10 +124,21 @@
for (i = 0; i < TVR_SIZE; i++)
INIT_LIST_HEAD(tv1.vec + i);

+#ifdef CONFIG_DEBUG_JIFFIESWRAP
+ tv1.index = INITIAL_JIFFIES & TVR_MASK;
+ tv2.index = (INITIAL_JIFFIES >> TVR_BITS) & TVN_MASK;
+ tv3.index = (INITIAL_JIFFIES >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
+ tv4.index = (INITIAL_JIFFIES >> (TVR_BITS + 2*TVN_BITS)) & TVN_MASK;
+ tv5.index = (INITIAL_JIFFIES >> (TVR_BITS + 3*TVN_BITS)) & TVN_MASK;
+
+ printk(KERN_NOTICE "Set up jiffies counter to wrap in %ld seconds.\n",
+ (-(long)jiffies)/HZ);
+#endif
+
init_jiffieswrap_timer();
}

-static unsigned long timer_jiffies;
+static unsigned long timer_jiffies = INITIAL_JIFFIES;

static inline void internal_add_timer(struct timer_list *timer)
{
@@ -668,7 +680,7 @@
}

/* jiffies at the most recent update of wall time */
-unsigned long wall_jiffies;
+unsigned long wall_jiffies = INITIAL_JIFFIES;

/*
* This spinlock protect us from races in SMP while playing with xtime. -arca

--- linux-2.4.20-pre7-j64/fs/proc/array.c Wed Sep 25 18:38:36 2002
+++ linux-2.4.20-pre7-j64-dbg/fs/proc/array.c Wed Sep 25 19:11:51 2002
@@ -369,7 +369,7 @@
nice,
0UL /* removed */,
task->it_real_value,
- (unsigned long long)(task->start_time),
+ (unsigned long long)(task->start_time) - INITIAL_JIFFIES,
vsize,
mm ? mm->rss : 0, /* you might want to shift this left 3 */
task->rlim[RLIMIT_RSS].rlim_cur,

--- linux-2.4.20-pre7-j64/fs/proc/proc_misc.c Wed Sep 25 18:53:38 2002
+++ linux-2.4.20-pre7-j64-dbg/fs/proc/proc_misc.c Wed Sep 25 19:11:51 2002
@@ -208,7 +208,7 @@
unsigned long uptime_remainder, idle_remainder;
int len;

- uptime = get_jiffies_64();
+ uptime = get_jiffies_64() - INITIAL_JIFFIES;
uptime_remainder = (unsigned long) do_div(uptime, HZ);
idle = get_sidle_64() + get_uidle_64();
idle_remainder = (unsigned long) do_div(idle, HZ);
@@ -386,7 +386,8 @@
int i, len = 0;
extern unsigned long total_forks;
unsigned int sum = 0;
- u64 jif = get_jiffies_64(), user = 0, nice = 0, system = 0;
+ u64 jif = get_jiffies_64() - INITIAL_JIFFIES;
+ u64 user = 0, nice = 0, system = 0;
int major, disk;

for (i = 0 ; i < smp_num_cpus; i++) {

--- linux-2.4.20-pre7-j64/kernel/info.c Wed Sep 25 18:38:36 2002
+++ linux-2.4.20-pre7-j64-dbg/kernel/info.c Wed Sep 25 19:11:51 2002
@@ -22,7 +22,7 @@
memset((char *)&val, 0, sizeof(struct sysinfo));

cli();
- uptime = get_jiffies_64();
+ uptime = get_jiffies_64() - INITIAL_JIFFIES;
do_div(uptime, HZ);
val.uptime = (unsigned long) uptime;

--- linux-2.4.20-pre7-j64/Documentation/Configure.help Wed Sep 25 18:33:43 2002
+++ linux-2.4.20-pre7-j64-dbg/Documentation/Configure.help Wed Sep 25 19:11:51 2002
@@ -25244,6 +25244,14 @@
of the BUG call as well as the EIP and oops trace. This aids
debugging but costs about 70-100K of memory.

+Debug jiffies counter wraparound (DANGEROUS)
+CONFIG_DEBUG_JIFFIESWRAP
+ Say Y here to initialize the jiffies counter to a value 5 minutes
+ before wraparound. This may make your system UNSTABLE and its
+ only use is to hunt down the causes of this instability.
+ If you don't know what the jiffies counter is or if you want
+ a stable system, say N.
+
Include kgdb kernel debugger
CONFIG_KGDB
Include in-kernel hooks for kgdb, the Linux kernel source level

--- linux-2.4.20-pre7-j64/arch/arm/config.in Wed Sep 25 18:33:43 2002
+++ linux-2.4.20-pre7-j64-dbg/arch/arm/config.in Wed Sep 25 19:11:51 2002
@@ -649,6 +649,7 @@
dep_bool ' Morse code panics' CONFIG_PANIC_MORSE $CONFIG_DEBUG_KERNEL $CONFIG_PC_KEYB
dep_bool ' Spinlock debugging' CONFIG_DEBUG_SPINLOCK $CONFIG_DEBUG_KERNEL
dep_bool ' Wait queue debugging' CONFIG_DEBUG_WAITQ $CONFIG_DEBUG_KERNEL
+dep_bool ' Debug jiffies counter wraparound (DANGEROUS)' CONFIG_DEBUG_JIFFIESWRAP $CONFIG_DEBUG_KERNEL
dep_bool ' Verbose BUG() reporting (adds 70K)' CONFIG_DEBUG_BUGVERBOSE $CONFIG_DEBUG_KERNEL
dep_bool ' Verbose kernel error messages' CONFIG_DEBUG_ERRORS $CONFIG_DEBUG_KERNEL
# These options are only for real kernel hackers who want to get their hands dirty.
--- linux-2.4.20-pre7-j64/arch/cris/config.in Wed Sep 25 18:33:43 2002
+++ linux-2.4.20-pre7-j64-dbg/arch/cris/config.in Wed Sep 25 19:11:51 2002
@@ -243,6 +243,7 @@
if [ "$CONFIG_SOUND" != "n" ]; then
source drivers/sound/Config.in
fi
+bool 'Debug jiffies counter wraparound (DANGEROUS)' CONFIG_DEBUG_JIFFIESWRAP
endmenu

source drivers/usb/Config.in

--- linux-2.4.20-pre7-j64/arch/i386/config.in Wed Sep 25 18:33:43 2002
+++ linux-2.4.20-pre7-j64-dbg/arch/i386/config.in Wed Sep 25 19:11:51 2002
@@ -451,6 +451,7 @@
bool ' Magic SysRq key' CONFIG_MAGIC_SYSRQ
bool ' Spinlock debugging' CONFIG_DEBUG_SPINLOCK
bool ' Compile the kernel with frame pointers' CONFIG_FRAME_POINTER
+ bool ' Debug jiffies counter wraparound (DANGEROUS)' CONFIG_DEBUG_JIFFIESWRAP
fi

endmenu

--- linux-2.4.20-pre7-j64/arch/m68k/config.in Wed Sep 25 18:33:43 2002
+++ linux-2.4.20-pre7-j64-dbg/arch/m68k/config.in Wed Sep 25 19:11:51 2002
@@ -552,6 +552,7 @@
if [ "$CONFIG_DEBUG_KERNEL" != "n" ]; then
bool ' Magic SysRq key' CONFIG_MAGIC_SYSRQ
bool ' Debug memory allocations' CONFIG_DEBUG_SLAB
+ bool ' Debug jiffies counter wraparound (DANGEROUS)' CONFIG_DEBUG_JIFFIESWRAP
bool ' Verbose BUG() reporting' CONFIG_DEBUG_BUGVERBOSE
fi

--- linux-2.4.20-pre7/arch/mips/config-shared.in Wed Sep 25 19:27:11 2002
+++ linux-2.4.20-pre7-j64/arch/mips/config-shared.in Wed Sep 25 19:15:30 2002
@@ -798,6 +798,7 @@
if [ "$CONFIG_SMP" != "y" ]; then
bool 'Run uncached' CONFIG_MIPS_UNCACHED
fi
+dep_bool 'Debug jiffies counter wraparound (DANGEROUS)' CONFIG_DEBUG_JIFFIESWRAP $CONFIG_MIPS32
endmenu

source lib/Config.in

--- linux-2.4.20-pre7-j64/arch/parisc/config.in Wed Sep 25 18:33:45 2002
+++ linux-2.4.20-pre7-j64-dbg/arch/parisc/config.in Wed Sep 25 19:11:51 2002
@@ -194,6 +194,7 @@

#bool 'Debug kmalloc/kfree' CONFIG_DEBUG_MALLOC
bool 'Magic SysRq key' CONFIG_MAGIC_SYSRQ
+bool 'Debug jiffies counter wraparound (DANGEROUS)' CONFIG_DEBUG_JIFFIESWRAP
endmenu

source lib/Config.in

--- linux-2.4.20-pre7-j64/arch/ppc/config.in Wed Sep 25 18:33:45 2002
+++ linux-2.4.20-pre7-j64-dbg/arch/ppc/config.in Wed Sep 25 19:17:13 2002
@@ -423,5 +423,6 @@
string ' Additional compile arguments' CONFIG_COMPILE_OPTIONS "-g -ggdb"
fi
fi
+ bool 'Debug jiffies counter wraparound (DANGEROUS)' CONFIG_DEBUG_JIFFIESWRAP
fi
endmenu

--- linux-2.4.20-pre7-j64/arch/sh/config.in Wed Sep 25 18:33:46 2002
+++ linux-2.4.20-pre7-j64-dbg/arch/sh/config.in Wed Sep 25 19:11:51 2002
@@ -385,6 +385,7 @@
if [ "$CONFIG_SH_STANDARD_BIOS" = "y" ]; then
bool 'Early printk support' CONFIG_SH_EARLY_PRINTK
fi
+bool 'Debug jiffies counter wraparound (DANGEROUS)' CONFIG_DEBUG_JIFFIESWRAP
endmenu

source lib/Config.in

--- linux-2.4.20-pre7-j64/arch/sparc/config.in Wed Sep 25 18:33:47 2002
+++ linux-2.4.20-pre7-j64-dbg/arch/sparc/config.in Wed Sep 25 19:11:51 2002
@@ -265,6 +265,7 @@
comment 'Kernel hacking'

bool 'Magic SysRq key' CONFIG_MAGIC_SYSRQ
+bool 'Debug jiffies counter wraparound (DANGEROUS)' CONFIG_DEBUG_JIFFIESWRAP
endmenu

source lib/Config.in