linux-kernel - Re: Are CAP_SYS_ADMIN and CAP_SYS

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Message-ID: <842e6993-8cde-bc00-4de1-7b8689a397a8@gmail.com>
Date:   Thu, 25 Mar 2021 13:44:10 +0000
From:   Pavel Begunkov <asml.silence@...il.com>
To:     Stefano Garzarella <sgarzare@...hat.com>,
        Jens Axboe <axboe@...nel.dk>
Cc:     io-uring@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: Are CAP_SYS_ADMIN and CAP_SYS_NICE still needed for SQPOLL?

On 25/03/2021 11:33, Stefano Garzarella wrote:
> Hi Jens, Hi Pavel,
> I was taking a look at the new SQPOLL handling with io_thread instead of kthread. Great job! Really nice feature that maybe can be reused also in other scenarios (e.g. vhost).
> 
> Regarding SQPOLL, IIUC these new threads are much closer to user threads, so is there still a need to require CAP_SYS_ADMIN and CAP_SYS_NICE to enable SQPOLL?

Hmm, good question. If there are under same cgroup (should be in
theory), and if we add more scheduling points (i.e. need_resched()), and
don't see a reason why not. Jens?

Better not right away though. IMHO it's safer to let the change settle
down for some time.

-- 
Pavel Begunkov