On 8/18/2016 7:48 PM, Imre Deak wrote:
On to, 2016-08-18 at 19:17 +0530, Goel, Akash wrote:
[...]
Thanks for the inputs. Sorry not familiar with freezable WQ semantics.
But after looking at code, this is what I understood :-
1. freezable Workqueues will be frozen before the system suspend
callbacks are invoked for the devices.
Yes.
2. Any work item queued after the WQ is marked frozen will be scheduled
later, on resume.
Yes.
3. But if a work item was already present in the freezable Workqueue,
before it was frozen and it did not complete, then system suspend
itself will be aborted.
System suspend will be aborted only if any kernel thread didn't
complete within a reasonable amount of time (freeze_timeout_msecs, 20
sec by default). Otherwise already queued items will be properly
waited upon and suspend will proceed.
Sorry for getting this wrong.
What I understood is that even if there are pending work items on
freezable WQ after freeze_timeout_msecs, then also system suspend would
be performed.
Sorry couldn't find an explicit/synchronous wait in kernel for the
pending work items for freezable WQs, but it doesn't matter.
4. So if the log.flush_wq is marked as freezable, then flush of
work item will not be required for the system suspend case.
And runtime suspend case is already covered with rpm get/put
around register access in work item function.
Yes.
It seems there are 2 config options CONFIG_SUSPEND_FREEZER
This is set whenever system suspend is enabled.
and
CONFIG_FREEZER
This is set except for one platform (powerpc), where I assume freezing
of the tasks is achieved in a different way. In any case it doesn't
matter for us.
Many thanks for providing all this info.
Will then mark the log.flush_wq as freezable.
Best regards
Akash
--Imre
which have to be enabled for all the above to happen.
If these config options will always be enabled then probably marking
log.flush_wq would work.
Please kindly confirm whether I understood correctly or not, accordingly
will proceed further.
Best regards
Akash
--Imre
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