Re: [RFC PATCH for 4.15 00/24] Restartable sequences and CPU op vector v11

[Mathieu Desnoyers]

Hi Paul!

I guess stuff like Spectre/Meltdown can turn 1-2 days into months. ;-)

I did not want to distract you too much from that work, but you'll notice
I've sent an updated patch series against 4.16-rc7, aiming at 4.17 [1]
(it should be in your inbox).

I would really appreciate if you can find time to provide feedback on
that version.

Congratulations on the wedding!

Thanks,

Mathieu

[1] https://lkml.kernel.org/r/20180327160542.28457-1-mathieu.desnoyers@xxxxxxxxxxxx

----- On Nov 14, 2017, at 4:32 PM, Paul Turner pjt@xxxxxxxxxx wrote:

> I have some comments that apply to many of the threads.
> I've been fully occupied with a wedding and a security issue; but I'm
> about to be free to spend the majority of my time on RSEQ things.
> I was sorely hoping that day would be today.  But it's looking like
> I'm still a day or two from being free for this.
> Thank you for the extensive clean-ups and user-side development.  I
> have some updates on these topics also.
> 
> - Paul
> 
> On Tue, Nov 14, 2017 at 1:15 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>> On Tue, Nov 14, 2017 at 1:08 PM, Linus Torvalds
>> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>>> On Tue, Nov 14, 2017 at 12:03 PM, Mathieu Desnoyers
>>> <mathieu.desnoyers@xxxxxxxxxxxx> wrote:
>>>> Here is the last RFC round of the updated rseq patchset containing:
>>>
>>> Andy? You were the one with concerns here and said you'd have
>>> something else ready for comparison.
>>>
>>
>> I had a long discussion with Mathieu and KS and I think that this is a
>> good compromise.  I haven't reviewed the series all that carefully,
>> but I think the idea is sound.
>>
>> Basically, event_counter is gone (to be re-added in a later kernel if
>> it really ends up being necessary, but it looks like it may primarily
>> be a temptation to write subtly incorrect user code and to see
>> scheduling details that shouldn't be readily exposed rather than a
>> genuinely useful feature) and the versioning mechanism for the asm
>> critical section bit is improved.  My crazy proposal should be doable
>> on top of this if there's demand and if anyone wants to write the
>> gnarly code involved.
>>
>> IOW no objection from me as long as those changes were made, which I
> > *think* they were.  Mathieu?

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com