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authorJiri Kosina <jkosina@suse.cz>2012-04-08 19:48:52 (GMT)
committerJiri Kosina <jkosina@suse.cz>2012-04-08 19:48:52 (GMT)
commite75d660672ddd11704b7f0fdb8ff21968587b266 (patch)
treeccb9c107744c10b553c0373e450bee3971d16c00 /Documentation/power/freezing-of-tasks.txt
parent61282f37927143e45b03153f3e7b48d6b702147a (diff)
parent0034102808e0dbbf3a2394b82b1bb40b5778de9e (diff)
downloadlinux-e75d660672ddd11704b7f0fdb8ff21968587b266.tar.xz
Merge branch 'master' into for-next
Merge with latest Linus' tree, as I have incoming patches that fix code that is newer than current HEAD of for-next. Conflicts: drivers/net/ethernet/realtek/r8169.c
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diff --git a/Documentation/power/freezing-of-tasks.txt b/Documentation/power/freezing-of-tasks.txt
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--- a/Documentation/power/freezing-of-tasks.txt
+++ b/Documentation/power/freezing-of-tasks.txt
@@ -63,6 +63,27 @@ devices have been reinitialized, the function thaw_processes() is called in
order to clear the PF_FROZEN flag for each frozen task. Then, the tasks that
have been frozen leave __refrigerator() and continue running.
+
+Rationale behind the functions dealing with freezing and thawing of tasks:
+-------------------------------------------------------------------------
+
+freeze_processes():
+ - freezes only userspace tasks
+
+freeze_kernel_threads():
+ - freezes all tasks (including kernel threads) because we can't freeze
+ kernel threads without freezing userspace tasks
+
+thaw_kernel_threads():
+ - thaws only kernel threads; this is particularly useful if we need to do
+ anything special in between thawing of kernel threads and thawing of
+ userspace tasks, or if we want to postpone the thawing of userspace tasks
+
+thaw_processes():
+ - thaws all tasks (including kernel threads) because we can't thaw userspace
+ tasks without thawing kernel threads
+
+
III. Which kernel threads are freezable?
Kernel threads are not freezable by default. However, a kernel thread may clear