page-writeback.c:(.text+0x6446): undefined reference to `____ilog2_NaN'

writeback-dirty-throttling-v7

[ gcc-4.5 ]

00006574 <calc_period_shift>:
    6574:       a1 90 00 00 00          mov    0x90,%eax        6575: R_386_32  default_backing_dev_info
    6579:       55                      push   %ebp
    657a:       89 e5                   mov    %esp,%ebp
    657c:       e8 02 f8 ff ff          call   5d83 <__ilog2_u32>
    6581:       5d                      pop    %ebp
    6582:       83 c0 02                add    $0x2,%eax

[ gcc-4.6 ]

00006463 <calc_period_shift>:
    6463:       55                      push   %ebp
    6464:       83 ca ff                or     $0xffffffff,%edx
    6467:       89 e5                   mov    %esp,%ebp
    6469:       0f bd 05 90 00 00 00    bsr    0x90,%eax        646c: R_386_32  default_backing_dev_info
    6470:       0f 44 c2                cmove  %edx,%eax
    6473:       5d                      pop    %ebp
    6474:       83 c0 02                add    $0x2,%eax
    6477:       c3                      ret