Messages in this thread | | | Date | Fri, 26 Apr 2019 19:40:19 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH v10 4/9] cgroup: cgroup v2 freezer |
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On 04/24, Roman Gushchin wrote: > > On Wed, Apr 24, 2019 at 05:46:19PM +0200, Oleg Nesterov wrote: > > > > OK, how about the ABSOLUTELY UNTESTED patch below? For the start. > > It looks good to me (and all freezer selftests pass). > > Just to be sure, is it a solution to avoid the busy loop in the signal handling > loop, right?
Yes,
> Because it doesn't allow to drop the ->frozen check from recalc().
Yes. Because we can race with unfreeze after leave_frozen().
> The JOBCTL_TRAP_FREEZE check without siglock initially looked dangerous to me, > but after some thoughts I didn't find any case when it's wrong.
I think this is fine... Yes, JOBCTL_TRAP_FREEZE can be already set when we take siglock, but I don't think we need to recheck this flag.
The only important thing (afaics) is that CGRP_FREEZE is stable under css_set_lock, so we can't wrongly set TRAP_FREEZE.
> Do you prefer me to master a patch
Yes please ;)
Oleg.
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