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Re: [Xen-devel] Only CPU0 active after ACPI S3, xen 4.1.3

On 16/01/13 13:08, Jan Beulich wrote:
On 16.01.13 at 12:58, George Dunlap <george.dunlap@xxxxxxxxxxxxx> wrote:
On 16/01/13 11:22, George Dunlap wrote:
Jan, the commit message isn't very informative -- can you point me to
Which commit message?

a conversation describing the problem you're fixing wrt
suspend/resume, and/or describe what you were trying to do?  Given the
results, the whole thing about not disabling scheduling during suspend
seems a bit suspect...
In particular, just on a fairly cursory bit of function call skimming,
it looks like:
* This change means that cpupool.c:cpu_callback() won't call
cpupool_cpu_add() when resuming
* cpupool_cpu_add() does a bunch of paperwork (which would be
unnecessary given the changes re suspend), but also calls
* cpupool_assign_cpu_locked() calls schedule_cpu_switch()
* schedule_cpu_switch() calls the scheduler's tick_resume()

So is it possible that on resume ticks are not being re-enabled, or
something like that?
I don't see a problem here - it's symmetric (nothing done on
suspend, and nothing done on resume).

Well it would be if it was only data, but it's not. That's my point. Before this changeset (xen-unstable 25079:d5ccb2d1dbd1), ticks were suspended and resumed on the CPU (i.e., timer interrupts turned off and on), and after the patch, they're not. Doesn't suspend disable / muck with timer interrupts?


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