linux-kernel - Re: [PATCHSET 0/2] PF_IO

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Message-ID: <a58f115e-2e42-8189-ca79-622db8289c3b@kernel.dk>
Date:   Sat, 20 Mar 2021 16:56:38 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Linus Torvalds <torvalds@...ux-foundation.org>,
        "Eric W. Biederman" <ebiederm@...ssion.com>
Cc:     io-uring <io-uring@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Oleg Nesterov <oleg@...hat.com>
Subject: Re: [PATCHSET 0/2] PF_IO_WORKER signal tweaks

On 3/20/21 1:18 PM, Linus Torvalds wrote:
> On Sat, Mar 20, 2021 at 10:51 AM Linus Torvalds
> <torvalds@...ux-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