Re: [PATCH v6 3/7] Reimplement RLIMIT_NPROC on top of ucounts

From: Jens Axboe <axboe@kernel.dk>
To: Alexey Gladkov <gladkov.alexey@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	io-uring@vger.kernel.org,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	Linux Containers <containers@lists.linux-foundation.org>,
	linux-mm@kvack.org
Cc: Alexey Gladkov <legion@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Christian Brauner <christian.brauner@ubuntu.com>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Jann Horn <jannh@google.com>, Kees Cook <keescook@chromium.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH v6 3/7] Reimplement RLIMIT_NPROC on top of ucounts
Date: Sun, 21 Feb 2021 16:38:10 -0700	[thread overview]
Message-ID: <72214339-57fc-e47f-bb57-d1b39c69e38e@kernel.dk> (raw)
In-Reply-To: <72fdcd154bec7e0dfad090f1af65ddac1e767451.1613392826.git.gladkov.alexey@gmail.com>

On 2/15/21 5:41 AM, Alexey Gladkov wrote:
> diff --git a/fs/io-wq.c b/fs/io-wq.c
> index a564f36e260c..5b6940c90c61 100644
> --- a/fs/io-wq.c
> +++ b/fs/io-wq.c
> @@ -1090,10 +1091,7 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
>  		wqe->node = alloc_node;
>  		wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded;
>  		atomic_set(&wqe->acct[IO_WQ_ACCT_BOUND].nr_running, 0);
> -		if (wq->user) {
> -			wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers =
> -					task_rlimit(current, RLIMIT_NPROC);
> -		}
> +		wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers = task_rlimit(current, RLIMIT_NPROC);

This doesn't look like an equivalent transformation. But that may be
moot if we merge the io_uring-worker.v3 series, as then you would not
have to touch io-wq at all.

-- 
Jens Axboe