<Early unpacking initramfs... done> message is printed by what f

slackit

dmesg output:
Freeing SMP alternatives: 11k freed
Early unpacking initramfs... done
ACPI: Core revision 20070126

   I want to known <Early unpacking initramfs... done> message is printed by what function and that function in what file of kernal source?

   I tried type "grep -r 'Early unpacking initramfs...' ./* 2> /dev/null" and in KScope find text 'Early unpacking initramfs...' but result was nothing, and then google also can not help me!

   So i hope anybody can help me in here!
   
   Thank very much!!

(kernel 2.6.21)