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Subject: Re: [PATCH 5/5] task_work: use TIF_NOTIFY_SIGNAL if available
To:     Thomas Gleixner <tglx@linutronix.de>,
        Oleg Nesterov <oleg@redhat.com>
Cc:     linux-kernel@vger.kernel.org, io-uring@vger.kernel.org,
        peterz@infradead.org, Roman Gershman <romger@amazon.com>
References: <20201015131701.511523-1-axboe@kernel.dk>
 <20201015131701.511523-6-axboe@kernel.dk> <20201015154953.GM24156@redhat.com>
 <e17cd91e-97b2-1eae-964b-fc90f8f9ef31@kernel.dk>
 <87a6wmv93v.fsf@nanos.tec.linutronix.de>
 <871rhyv7a8.fsf@nanos.tec.linutronix.de>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <fbaab94b-dd85-9756-7a99-06bf684b80a4@kernel.dk>
Date:   Fri, 16 Oct 2020 07:35:44 -0600
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On 10/16/20 3:39 AM, Thomas Gleixner wrote:
> On Fri, Oct 16 2020 at 11:00, Thomas Gleixner wrote:
>> On Thu, Oct 15 2020 at 12:39, Jens Axboe wrote:
>>> On 10/15/20 9:49 AM, Oleg Nesterov wrote:
>> So if you change #2 to:
>>
>>    Drop the CONFIG_GENERIC_ENTRY dependency, make _all_ architectures
>>    use TIF_NOTIFY_SIGNAL and clean up the jobctl and whatever related
>>    mess.
>>
>> and actually act apon it, then I'm fine with that approach.
> 
> Which makes me rethink my view on Olegs suggestion:
> 
>>>> You can simply nack the patch which adds TIF_NOTIFY_SIGNAL to
>>>> arch/xxx/include/asm/thread_info.h.
> 
> That's a truly great suggestion:
> 
>    X86 is going to have that TIF bit once the above is available.
> 
> I'm happy to help with the merge logistics of this.

Not really following this email...

But it seems to me that you're happy with approach 2, so I'll do
the following:

- Get rid of the CONFIG_GENERIC_ENTRY dependency for TIF_NOTIFY_SIGNAL
- Respin the arch additions and cleanups on top of that again

And hopefully we'll have something mergeable at that point. Once we
have this series merged somewhere (would be great if you could carry
it), I'll be talking to arch folks on the rest. Once archs have taken
the necessary bits, I'll be posting the third and final series which
is the cleanups that are currently sitting on top of the arch support.

-- 
Jens Axboe