Messages in this thread | | | From | Peter Newman <> | Date | Wed, 7 Dec 2022 12:04:47 +0100 | Subject | Re: [PATCH v4 2/2] x86/resctrl: IPI all online CPUs for group updates |
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Hi Reinette,
On Tue, Dec 6, 2022 at 7:57 PM Reinette Chatre <reinette.chatre@intel.com> wrote: > On 11/29/2022 3:10 AM, Peter Newman wrote: > > Removing a CTRL_MON or MON group directory moves all tasks to the parent > > group. The rmdir implementation therefore interrupts any running > > tasks which were in the deleted group to update their CLOSID/RMID to > > those of the parent. > > > > The rmdir operation iterates over all tasks in the deleted group while > > read-locking the tasklist_lock to ensure that no newly-created child > > tasks remain in the deleted group. > > The above describes the current behavior. This is great context. What > follows in the changelog is a description of different fixes. This is > unexpected because there is no description of a problem with the current > behavior. > > Could you please describe the problem with the current implementation? Next > you could state the two possible solutions and then I think the reader would > be ready to parse what is written below.
Ok
> > Calling task_call_func() to perform > > the updates on every task in the deleted group, similar to the recent > > fix in __rdtgroup_move_task(), would result in a much longer > > tasklist_lock critical section. > > > I so still think it would help to state that this additional locking > does not help to provide precise CPU mask. Especially since > the next paragraph may be interpreted that a precise CPU mask > is lost by giving up the additional locking.
Yes, that's a very good point, and I'm afraid I've already made you reiterate it once before. I will make sure to work it into the next revision.
-Peter
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