From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 022DEC433F5 for ; Fri, 17 Sep 2021 07:44:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD755611C0 for ; Fri, 17 Sep 2021 07:44:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239103AbhIQHqH (ORCPT ); Fri, 17 Sep 2021 03:46:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:37332 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231263AbhIQHqF (ORCPT ); Fri, 17 Sep 2021 03:46:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7B04C60F38; Fri, 17 Sep 2021 07:44:42 +0000 (UTC) Date: Fri, 17 Sep 2021 09:44:40 +0200 From: Christian Brauner To: Christoph Hellwig Cc: Mike Christie , stefanha@redhat.com, jasowang@redhat.com, mst@redhat.com, sgarzare@redhat.com, virtualization@lists.linux-foundation.org, axboe@kernel.dk, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/8] fork: add helper to clone a process Message-ID: <20210917074440.qwo6anrtxa7lj657@wittgenstein> References: <20210916212051.6918-1-michael.christie@oracle.com> <20210916212051.6918-2-michael.christie@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 17, 2021 at 07:00:35AM +0100, Christoph Hellwig wrote: > On Thu, Sep 16, 2021 at 04:20:44PM -0500, Mike Christie wrote: > > The vhost layer has similar requirements as io_uring where its worker > > threads need to access the userspace thread's memory, want to inherit the > > parents's cgroups and namespaces, and be checked against the parent's > > RLIMITs. Right now, the vhost layer uses the kthread API which has > > kthread_use_mm for mem access, and those threads can use > > cgroup_attach_task_all for v1 cgroups, but there are no helpers for the > > other items. > > > > This adds a helper to clone a process so we can inherit everything we > > want in one call. It's a more generic version of create_io_thread which > > will be used by the vhost layer and io_uring in later patches in this set. > > > > This patch also exports __set_task_comm and wake_up_new_task which is > > needed by modules to use the new helper. io_uring calls these functions > > already but its always built into the kernel so was not needed before. > > Can you build proper APIs please? e.g. the set_task_comm users > generally want a printf-like varargs caling conventions. I'd also > much prefer to hide as much as possible in the actual helper. That is > build a helper that gets the name, a flag to ignore the singals etc > instead of exporting all these random low-level helpers. Yes, I think that's really what we want here.