Re: [RFC] Fix SMP brokenness for PF_FREEZE and make freezing usable for other purposes

Hi!

quoted

quoted

 -			freeze(p);
+			set_thread_flag(TIF_FREEZE);

Shouldn't that be "set_ti_thread_flag(p->thread_info, TIF_FREEZE)"?
Otherwise you freeze current, not the thread "p".

Correct. Which also means that we have not progressed yet beyond an 
academic version of the patch:

---

Revise handling of freezing in the suspend code

The current suspend code modifies thread flags from outside the context of process.
This creates a SMP race.

The patch fixes that by introducing a TIF_FREEZE flag (for all arches). Also

- Uses a completion handler instead of waiting in a schedule loop in the refrigerator.

- Introduces a semaphore freezer_sem to provide a way that multiple kernel
  subsystems can use the freezing ability without interfering with one another.

- Include necessary definitions for the migration code if CONFIG_MIGRATE is set.

- Removes PF_FREEZE

Signed-off-by: Christoph Lameter <redacted>

This patch breaks suspend for me (first suspend works, second suspend
fails to freeze processes). [I was offline, that's why it took so
long.]

I see patches 1/2 and 2/2 submitted; if you still feel I should apply
some of them, tell me.
								Pavel

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