==================================
ϡ
linux-2.6.13-rc4/Documentation/power/kernel_threads.txt 
Ǥ
Ρ JF ץ < http://www.linux.or.jp/JF/ >
  2005/8/6
  Hiroshi.Suzuki < setter at reset dot jp >
  Chie Nakatani  <jeanne at mbox dot kyoto-inet dot or dot jp>
         Seiji Kaneko  <skaneko at a2 dot mbn dot or dot jp>
==================================

KERNEL THREADS

ͥ륹å

Freezer

(ե꡼)

Upon entering a suspended state the system will freeze all
tasks. This is done by delivering pseudosignals. This affects
kernel threads, too. To successfully freeze a kernel thread
the thread has to check for the pseudosignal and enter the
refrigerator. Code to do this looks like this:

ڥɾ֤ˤʤȤƥϤ٤ƤΥ뤷ޤ
ϡʥ뤳ȤǹԤ졢ͥ륹åɤˤѤޤ
ͥ륹åɤ뤹ˤϡͥ륹åɤʥ򸡽Фơ
¢(ٻ߾)ʤФʤޤ󡣼¹Ԥ뤿ΥɤϼΤ褦ˤʤޤ:

	do {
		hub_events();
		wait_event_interruptible(khubd_wait, !list_empty(&hub_event_list));
		try_to_freeze();
	} while (!signal_pending(current));

from drivers/usb/core/hub.c::hub_thread()

drivers/usb/core/hub.c::hub_thread() ꡢȴ衣

The Unfreezable

Ǥʤ

Some kernel threads however, must not be frozen. The kernel must
be able to finish pending IO operations and later on be able to
write the memory image to disk. Kernel threads needed to do IO
must stay awake. Such threads must mark themselves unfreezable
like this:

뤷ƤϤʤͥ륹åɤ⤢ޤ
ͥα ϽλȤˡꥤ᡼ǥ
񤭹ʤФʤޤϽԤɬפʥͥ륹åɤ
ư֤ǤʤФޤ󡣤Τ褦ʥåɤϡΤ褦ǽǤ
򼫿ȤˤĤƤϤǤ

	/*
	 * This thread doesn't need any user-level access,
	 * so get rid of all our resources.
	 */

	/*
	 * ΥåɤϤɤʥ桼٥륢פʤΤǡ
	 * ٤ƤΥ꥽Ƥ
	 */

	daemonize("usb-storage");

	current->flags |= PF_NOFREEZE;

from drivers/usb/storage/usb.c::usb_stor_control_thread()

drivers/usb/storage/usb.c::usb_stor_control_thread() ꡢȴ衣

Such drivers are themselves responsible for staying quiet during
the actual snapshotting.

ºݤ˥ʥåץåȤԤݤˡŤˤƤΤϤΤ褦ʥɥ饤Ф¦ǤǤ
