Can jiffies freeze?

[Valdis.Kletnieks at vt.edu]

On Tue, 22 Jan 2013 10:29:05 -0800, sandeep kumar said:

> I am seeing this problem at the very early in the start_kernel-->
> mm_init--> free_highpages, at that time nothing is up and kernel is running
> in single thread.

If you build a kernel with printk timestamps, you'll see that they all
come out like this:

[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Linux version 3.8.0-rc3-next-20130117-dirty (valdis at turing-police.cc.vt.edu) (gcc version 4.7.2 20121109 (Red Hat 4.7.2-9) (GCC) ) #49 SMP PREEMPT Thu Jan 17 13:25:28 EST 2013
[    0.000000] Command line: ro root=/dev/mapper/vg_blackice-root log_buf_len=2M vga=893 loglevel=4 threadirqs intel_iommu=off LANG=en_US.UTF-8
[    0.000000] KERNEL supported cpus:
[    0.000000]   Intel GenuineIntel
[    0.000000] e820: BIOS-provided physical RAM map:
[    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009bbff] usable
[    0.000000] BIOS-e820: [mem 0x000000000009bc00-0x000000000009ffff] reserved
(100 or so more lines with same timestamp)
(now we finish memory init)
[    0.000000] Dentry cache hash table entries: 524288 (order: 10, 4194304 bytes)
[    0.000000] Inode-cache hash table entries: 262144 (order: 9, 2097152 bytes)
[    0.000000] __ex_table already sorted, skipping sort
[    0.000000] xsave: enabled xstate_bv 0x3, cntxt size 0x240
[    0.000000] Memory: 4015936k/4718592k available (6266k kernel code, 536744k absent, 165912k reserved, 7260k data, 576k init)
(more lines skipped)
[    0.000000]  memory used by lock dependency info: 5855 kB
[    0.000000]  per task-struct memory footprint: 1920 bytes
[    0.000000] hpet clockevent registered
[    0.000000] tsc: Fast TSC calibration using PIT
[    0.000000] tsc: Detected 2527.012 MHz processor
[    0.001004] Calibrating delay loop (skipped), value calculated using timer frequency.. 5054.02 BogoMIPS (lpj=2527012)
[    0.001009] pid_max: default: 32768 minimum: 301
[    0.001100] Security Framework initialized

It probably simply be that your code is running before the clock is started
by the kernel.
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