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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 A3DFFC43331 for ; Mon, 11 Nov 2019 16:32:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 751E020656 for ; Mon, 11 Nov 2019 16:32:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KyWHP9qC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726954AbfKKQcR (ORCPT ); Mon, 11 Nov 2019 11:32:17 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:49403 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726857AbfKKQcR (ORCPT ); Mon, 11 Nov 2019 11:32:17 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573489935; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LqK12N2BhrocKRvl7cMiEaZz6qD/oH8PM0mBXIIjGWk=; b=KyWHP9qCwp+LoxxT6Ijj3Bz8QmuQYVIRaobpUtkGRZjI++E9mebk/5yyla3KnXTuswwqzP chJRCcxJesKS9aU5A94Xesenv2GvIVT1nw4DixIv0ZBoKbj0HRnXbPynVmrwMSbUma/zoE +j9GEqxGVuF/HiO5+JVPMqr66YMR3s4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-99-s9OhPxAAPJu1OgSJnyNOCw-1; Mon, 11 Nov 2019 11:32:14 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6391DDC59; Mon, 11 Nov 2019 16:32:13 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.43.17.44]) by smtp.corp.redhat.com (Postfix) with SMTP id 524A06106C; Mon, 11 Nov 2019 16:32:11 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Mon, 11 Nov 2019 17:32:13 +0100 (CET) Date: Mon, 11 Nov 2019 17:32:10 +0100 From: Oleg Nesterov To: Christian Brauner Cc: Adrian Reber , Eric Biederman , Pavel Emelyanov , Jann Horn , Dmitry Safonov <0x7f454c46@gmail.com>, linux-kernel@vger.kernel.org, Andrei Vagin , Mike Rapoport , Radostin Stoyanov Subject: Re: [PATCH v7 1/2] fork: extend clone3() to support setting a PID Message-ID: <20191111163209.GB11389@redhat.com> References: <20191111131704.656169-1-areber@redhat.com> <20191111152514.GA11389@redhat.com> <20191111154028.GF514519@dcbz.redhat.com> <20191111161458.fjodxyx566dar6ob@wittgenstein> MIME-Version: 1.0 In-Reply-To: <20191111161458.fjodxyx566dar6ob@wittgenstein> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: s9OhPxAAPJu1OgSJnyNOCw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/11, Christian Brauner wrote: > > On Mon, Nov 11, 2019 at 04:40:28PM +0100, Adrian Reber wrote: > > > note also that this way we can easily allow set_tid[some_level] =3D= =3D 0, we can > > > simply do > > > > > > =09-=09if (xxx < 1 || xxx >=3D pid_max) > > > =09+=09if (xxx < 0 || xxx >=3D pid_max) > > > > > > although I don't think this is really useful. > > > > Yes. I explicitly didn't allow 0 as a PID as I didn't thought it would > > be useful (or maybe even valid). > > How do you express: I don't care about a specific pid in pidns level > , Yes, > Wouldn't that be potentially useful? As I said above, I don't think this is really useful. Just I was thinking out loud. I suggested to cache set_tid[pos] rather than pos because this makes the code simpler, not because this allows this allows to "naturally" handle the case when set_tid[pos] =3D=3D 0. Sorry it it was not clear. Oleg.