Documentation/power/freezing-of-tasks.rst

11 kernel threads are controlled during hibernation or system-wide suspend (on some
17 There are three per-task flags used for that, PF_NOFREEZE, PF_FROZEN
25 freeze_processes() (defined in kernel/power/process.c) is called.  A system-wide
26 variable system_freezing_cnt (as opposed to a per-task flag) is used to indicate
44 signal-handling code, but the freezable kernel threads need to call it
74 -------------------------------------------------------------------------
77   - freezes only userspace tasks
80   - freezes all tasks (including kernel threads) because we can't freeze
84   - thaws only kernel threads; this is particularly useful if we need to do
89   - thaws all tasks (including kernel threads) because we can't thaw userspace
111    filesystem-related information that must be consistent with the state of the
112    on-disk data and metadata after the system memory state has been restored
115    tasks that might cause the on-disk filesystems' data and metadata to be
137 … on LKML (https://lore.kernel.org/r/alpine.LFD.0.98.0704271801020.9964@woody.linux-foundation.org):
162    space processes should not notice that such a system-wide operation has
171 V. Are there any problems related to the freezing of tasks?
182 Second, there are the following two problems related to the freezing of user
189    (https://lists.linux-foundation.org/pipermail/linux-pm/2007-May/012309.html).
198 they are not directly related to it.  For example, if request_firmware() is
205 is used.  Consequently, the problem is not really related to the freezing of
211 Documentation/driver-api/pm/notifiers.rst.
219 piece of code from system-wide sleep such as suspend/hibernation is not
222 CPU-Hotplug code (kernel/cpu.c) for an example.