Add 99memstrack module

Add 99memstrack module

memstrack is a new tool to track the overall memory usage and
allocation, which can help off load the improve the builtin module
memory tracing function in dracut.

With this change, the rd.memdebug=4 behavior is similiar with before,
but the report is defered to pre-pivot, so the memory usage info
during the whole initramfs run is traced. And the ourput format is
changed a bit:

  dracut-pre-pivot[519]: ======== Report format module_summary: ========
  dracut-pre-pivot[519]: Module squashfs using 10.4MB (2658 pages), peak allocation 10.4MB (2671 pages)
  dracut-pre-pivot[519]: Module qxl using 3.4MB (865 pages), peak allocation 3.4MB (880 pages)
  dracut-pre-pivot[519]: Module crc32c_intel using 2.0MB (519 pages), peak allocation 3.0MB (769 pages)
  dracut-pre-pivot[519]: Module serio_raw using 2.0MB (505 pages), peak allocation 3.6MB (918 pages)
  dracut-pre-pivot[519]: Module virtio_console using 1.6MB (416 pages), peak allocation 1.6MB (419 pages)
  ... snip ...
  dracut-pre-pivot[519]: ======== Report format module_summary END ========

It now contains more detail and also includes the peak usage which could
be more helpful.

And now it have a rd.memdebug=5, which will print more detail about
the stack trace of the top memory user, also printed on pri-pivot:

  dracut-pre-pivot[519]: ======== Report format module_top: ========
  dracut-pre-pivot[519]: Top stack usage of module squashfs:
  dracut-pre-pivot[519]:   (null) Pages: 2658 (peak: 2671)
  dracut-pre-pivot[519]:     (null) Pages: 2658 (peak: 2671)
  dracut-pre-pivot[519]:       async_page_fault (0xffffffff81a01149) Pages: 1448 (peak: 1461)
  dracut-pre-pivot[519]:         do_async_page_fault (0xffffffff8105c509) Pages: 1448 (peak: 1461)
  dracut-pre-pivot[519]:           do_page_fault (0xffffffff8106296a) Pages: 1448 (peak: 1461)
  dracut-pre-pivot[519]:             do_user_addr_fault (0xffffffff810626bd) Pages: 1448 (peak: 1461)
  dracut-pre-pivot[519]:               handle_mm_fault (0xffffffff812940c4) Pages: 1448 (peak: 1461)
  dracut-pre-pivot[519]:                 __handle_mm_fault (0xffffffff81293627) Pages: 1195 (peak: 1208)
  dracut-pre-pivot[519]:                   __do_fault (0xffffffff8128b07e) Pages: 1195 (peak: 1208)
  dracut-pre-pivot[519]:                     filemap_fault (0xffffffff8124c0b9) Pages: 1195 (peak: 1208)
  dracut-pre-pivot[519]:                       __do_page_cache_readahead (0xffffffff812585da) Pages: 1063 (peak: 1076)
  dracut-pre-pivot[519]:                         read_pages (0xffffffff812583c2) Pages: 1063 (peak: 1076)
  dracut-pre-pivot[519]:                           squashfs_readpage squashfs (0xffffffffc0022073) Pages: 1039 (peak: 1052)
  dracut-pre-pivot[519]:                             squashfs_readpage_block squashfs (0xffffffffc0024334) Pages: 744 (peak: 744)
  dracut-pre-pivot[519]:                               squashfs_copy_cache squashfs (0xffffffffc0021a3f) Pages: 744 (peak: 744)
  dracut-pre-pivot[519]:                                 pagecache_get_page (0xffffffff8124abf7) Pages: 744 (peak: 744)
  dracut-pre-pivot[519]:                                   __page_cache_alloc (0xffffffff81247df6) Pages: 744 (peak: 744)
  dracut-pre-pivot[519]:                                     alloc_pages_current (0xffffffff812cdca7) Pages: 744 (peak: 744)
  dracut-pre-pivot[519]:                                       __alloc_pages_nodemask (0xffffffff812b3107) Pages: 744 (peak: 744)
  dracut-pre-pivot[519]:                                         __alloc_pages_nodemask (0xffffffff812b3107) Pages: 1488 (peak: 1488)
  dracut-pre-pivot[519]: Top stack usage of module qxl:
  dracut-pre-pivot[519]:   (null) Pages: 865 (peak: 880)
  dracut-pre-pivot[519]:     entry_SYSCALL_64_after_hwframe (0xffffffff81a0008c) Pages: 855 (peak: 858)
  dracut-pre-pivot[519]:       do_syscall_64 (0xffffffff81002a5a) Pages: 855 (peak: 858)
  dracut-pre-pivot[519]:         __x64_sys_finit_module (0xffffffff8117ccea) Pages: 811 (peak: 811)
  dracut-pre-pivot[519]:           __do_sys_finit_module (0xffffffff8117cc6e) Pages: 811 (peak: 811)
  dracut-pre-pivot[519]:             load_module (0xffffffff8117c6be) Pages: 802 (peak: 802)
  dracut-pre-pivot[519]:               do_init_module (0xffffffff81179e72) Pages: 802 (peak: 802)
  dracut-pre-pivot[519]:                 do_one_initcall (0xffffffff81000d5a) Pages: 802 (peak: 802)
  dracut-pre-pivot[519]:                   serio_raw_poll serio_raw (0xffffffffc0200054) Pages: 802 (peak: 802)
  dracut-pre-pivot[519]:                     __pci_register_driver (0xffffffff81557804) Pages: 802 (peak: 802)
  dracut-pre-pivot[519]:                       driver_register (0xffffffff8167ed24) Pages: 802 (peak: 802)
  dracut-pre-pivot[519]:                         bus_add_driver (0xffffffff8167cbb2) Pages: 801 (peak: 801)
  dracut-pre-pivot[519]:                           driver_attach (0xffffffff8167d28e) Pages: 801 (peak: 801)
  dracut-pre-pivot[519]:                             bus_for_each_dev (0xffffffff8167b62c) Pages: 801 (peak: 801)
  dracut-pre-pivot[519]:                               __driver_attach (0xffffffff8167e18f) Pages: 801 (peak: 801)
  dracut-pre-pivot[519]:                                 device_driver_attach (0xffffffff8167e0ed) Pages: 801 (peak: 801)
  dracut-pre-pivot[519]:                                   driver_probe_device (0xffffffff8167de6c) Pages: 801 (peak: 801)
  dracut-pre-pivot[519]:                                     really_probe (0xffffffff8167d9c9) Pages: 801 (peak: 801)
  dracut-pre-pivot[519]:                                       pci_device_probe (0xffffffff81559627) Pages: 801 (peak: 801)
  dracut-pre-pivot[519]:                                         local_pci_probe (0xffffffff81557f98) Pages: 801 (peak: 801)
  dracut-pre-pivot[519]:                                           qxl_pci_probe qxl (0xffffffffc01f0387) Pages: 773 (peak: 773)
  dracut-pre-pivot[519]:                                             drm_fbdev_generic_setup drm_kms_helper (0xffffffffc01b30c5) Pages: 773 (peak: 773)
  dracut-pre-pivot[519]:                                               drm_fbdev_client_hotplug drm_kms_helper (0xffffffffc01b2656) Pages: 773 (peak: 773)
  dracut-pre-pivot[519]:                                                 __drm_fb_helper_initial_config_and_unlock drm_kms_helper (0xffffffffc01b1a28) Pages: 770 (peak: 770)
  dracut-pre-pivot[519]:                                                   drm_fb_helper_generic_probe drm_kms_helper (0xffffffffc01b2fa5) Pages: 770 (peak: 770)
  dracut-pre-pivot[519]:                                                     vzalloc (0xffffffff812aa39c) Pages: 770 (peak: 770)
  dracut-pre-pivot[519]:                                                       __vmalloc_node_range (0xffffffff812aa200) Pages: 768 (peak: 768)
  ... snip ...
  ======== Report format module_top END ========

This could be very helpful for debuging memory usage issues.