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authorLinus Torvalds <torvalds@linux-foundation.org>2017-11-13 18:23:19 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-13 18:23:19 -0800
commit7d58e1c9059eefe0066c5acf2ffa582f6f0180e3 (patch)
tree265d08c51c7f303f49b792b2362ee5f943e1c2e2 /Documentation/power
parent2bcc673101268dc50e52b83226c5bbf38391e16d (diff)
parentf4c09f87adfe31587aa4b2aea2cb2dbde2150f54 (diff)
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull smp/hotplug updates from Thomas Gleixner: "No functional changes, just removal of obsolete and outdated defines, macros and documentation" * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: cpu/hotplug: Get rid of CPU hotplug notifier leftovers cpu/hotplug: Remove obsolete notifier macros
Diffstat (limited to 'Documentation/power')
-rw-r--r--Documentation/power/suspend-and-cpuhotplug.txt9
1 files changed, 4 insertions, 5 deletions
diff --git a/Documentation/power/suspend-and-cpuhotplug.txt b/Documentation/power/suspend-and-cpuhotplug.txt
index 2fc909502db5..31abd04b9572 100644
--- a/Documentation/power/suspend-and-cpuhotplug.txt
+++ b/Documentation/power/suspend-and-cpuhotplug.txt
@@ -232,7 +232,7 @@ d. Handling microcode update during suspend/hibernate:
hibernate/restore cycle.]
In the current design of the kernel however, during a CPU offline operation
- as part of the suspend/hibernate cycle (the CPU_DEAD_FROZEN notification),
+ as part of the suspend/hibernate cycle (cpuhp_tasks_frozen is set),
the existing copy of microcode image in the kernel is not freed up.
And during the CPU online operations (during resume/restore), since the
kernel finds that it already has copies of the microcode images for all the
@@ -252,10 +252,9 @@ Yes, they are listed below:
the _cpu_down() and _cpu_up() functions is *always* 0.
This might not reflect the true current state of the system, since the
tasks could have been frozen by an out-of-band event such as a suspend
- operation in progress. Hence, it will lead to wrong notifications being
- sent during the cpu online/offline events (eg, CPU_ONLINE notification
- instead of CPU_ONLINE_FROZEN) which in turn will lead to execution of
- inappropriate code by the callbacks registered for such CPU hotplug events.
+ operation in progress. Hence, the cpuhp_tasks_frozen variable will not
+ reflect the frozen state and the CPU hotplug callbacks which evaluate
+ that variable might execute the wrong code path.
2. If a regular CPU hotplug stress test happens to race with the freezer due
to a suspend operation in progress at the same time, then we could hit the