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Subject: Re: [PATCHSET 0/2] PF_IO_WORKER signal tweaks
To:     Linus Torvalds <torvalds@linux-foundation.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>
Cc:     io-uring <io-uring@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Oleg Nesterov <oleg@redhat.com>
References: <20210320153832.1033687-1-axboe@kernel.dk>
 <m14kh5aj0n.fsf@fess.ebiederm.org>
 <CAHk-=whyL6prwWR0GdgxLZm_w-QWwo7jPw_DkEGYFbMeCdo8YQ@mail.gmail.com>
 <CAHk-=wh3DCgezr5RKQ4Mqffoj-F4i47rp85Q4MSFRNhrr8tg3w@mail.gmail.com>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <a58f115e-2e42-8189-ca79-622db8289c3b@kernel.dk>
Date:   Sat, 20 Mar 2021 16:56:38 -0600
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On 3/20/21 1:18 PM, Linus Torvalds wrote:
> On Sat, Mar 20, 2021 at 10:51 AM Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
>>
>> Alternatively, make it not use
>> CLONE_SIGHAND|CLONE_THREAD at all, but that would make it
>> unnecessarily allocate its own signal state, so that's "cleaner" but
>> not great either.
> 
> Thinking some more about that, it would be problematic for things like
> the resource counters too. They'd be much better shared.
> 
> Not adding it to the thread list etc might be clever, but feels a bit too scary.

That would be my immediate concern - it might very well be the right long
term solution, but I'd be wary of doing it upfront and having weird fallout
due to it.

> So on the whole I think Jens' minor patches to just not have IO helper
> threads accept signals are probably the right thing to do.

I do think we should just go with those two - they are simple and
straight forward. I'm also totally fine replacing 2/2 with Eric's
variant if he prefers that, I've confirmed that it works fine for me as
well.

-- 
Jens Axboe