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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 5401CC6778F for ; Thu, 26 Jul 2018 15:55:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04FC12064D for ; Thu, 26 Jul 2018 15:55:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 04FC12064D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731958AbeGZRNQ (ORCPT ); Thu, 26 Jul 2018 13:13:16 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:59308 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730298AbeGZRNQ (ORCPT ); Thu, 26 Jul 2018 13:13:16 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4926B87927; Thu, 26 Jul 2018 15:55:49 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.34.27.30]) by smtp.corp.redhat.com (Postfix) with SMTP id C6A9521568A1; Thu, 26 Jul 2018 15:55:47 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 26 Jul 2018 17:55:49 +0200 (CEST) Date: Thu, 26 Jul 2018 17:55:47 +0200 From: Oleg Nesterov To: "Eric W. Biederman" Cc: Linus Torvalds , Andrew Morton , Linux Kernel Mailing List , Wen Yang , majiang Subject: Re: [PATCH v3 20/20] signal: Don't restart fork when signals come in. Message-ID: <20180726155546.GA467@redhat.com> References: <874lgo5xdg.fsf@xmission.com> <87fu084cxj.fsf@xmission.com> <87a7qg4bb3.fsf_-_@xmission.com> <87pnzc2upf.fsf@xmission.com> <87k1pk2cj9.fsf_-_@xmission.com> <20180726134143.GB32718@redhat.com> <87pnza6ou2.fsf@xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87pnza6ou2.fsf@xmission.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Thu, 26 Jul 2018 15:55:49 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Thu, 26 Jul 2018 15:55:49 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'oleg@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/26, Eric W. Biederman wrote: > > Are the earlier patches looking ok to you? I obviously like 1-15. "[PATCH 16/20] fork: Move and describe why the code examines PIDNS_ADDING" is "interesting". I mean it is fine, but at the end of this series it doesn't matter what we check first, PIDNS_ADDING or fatal_signal_pending() - restart is not possible in both cases. As for 17-20... Yes I am biased. But I still think the simple approach I tried to propose from the very beginning is better. At least simpler, in that you do not need to worry about all these special cases/reasons for signal_pending(). And you can not imagine how much I hate "[PATCH 19/20] fork: Have new threads join on-going signal group stops" ;) Because I spent HOURS looking at this trivial patch and I am still not sure... To clarify, the CLONE_THREAD with JOBCTL_STOP_PENDING case is simple, I am mostly worried about JOBCTL_TRAP_STOP/etc with or without CLONE_THREAD, this adds some subtle changes but unfortunately I failed to find something wrong so I can't argue. Oleg.