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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 5CDB2C43331 for ; Mon, 11 Nov 2019 09:41:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 335AE20818 for ; Mon, 11 Nov 2019 09:41:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JqdEErT9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726985AbfKKJli (ORCPT ); Mon, 11 Nov 2019 04:41:38 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:48070 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726857AbfKKJlh (ORCPT ); Mon, 11 Nov 2019 04:41:37 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573465296; 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=xH9paoH84WAP3S/ATWHs4L3GR0FO8tvE2c1L9kietRg=; b=JqdEErT9cwFYr3CMZgBawGC4ZWMKWqG7hNf49a4Zb4h2m5G30ymEJKS8cZVAX2uqGArDE0 of9xl9Q6q8mFhfMiC9Kga9uiOd3BhvPrXmH0c6PB2jW3VppZy8JjdqC77VjCUK6N05VwKv JQmMQJ9YvqrXIaA6TRDQU9ng+ppFejs= 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-412-_hgx6tiHOsGX5hz3cbUKkA-1; Mon, 11 Nov 2019 04:41:35 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1BA28477; Mon, 11 Nov 2019 09:41:34 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 103AE5DA7D; Mon, 11 Nov 2019 09:41:34 +0000 (UTC) Received: from zmail17.collab.prod.int.phx2.redhat.com (zmail17.collab.prod.int.phx2.redhat.com [10.5.83.19]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id ED0854BB5C; Mon, 11 Nov 2019 09:41:33 +0000 (UTC) Date: Mon, 11 Nov 2019 04:41:33 -0500 (EST) From: Jan Stancek To: Peter Zijlstra , Thomas Gleixner Cc: linux-kernel@vger.kernel.org, ltp@lists.linux.it, viro@zeniv.linux.org.uk, kstewart@linuxfoundation.org, gregkh@linuxfoundation.org, rfontana@redhat.com Message-ID: <475677126.11444968.1573465293662.JavaMail.zimbra@redhat.com> In-Reply-To: <20191107125559.GI4131@hirez.programming.kicks-ass.net> References: <20191107123224.GA6315@hirez.programming.kicks-ass.net> <20191107125559.GI4131@hirez.programming.kicks-ass.net> Subject: Re: [PATCH] kernel: use ktime_get_real_ts64() to calculate acct.ac_btime MIME-Version: 1.0 X-Originating-IP: [10.43.17.163, 10.4.195.4] Thread-Topic: kernel: use ktime_get_real_ts64() to calculate acct.ac_btime Thread-Index: j00i/ne0YYWt2EQwNR0Jpc5QU9IvTg== X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-MC-Unique: _hgx6tiHOsGX5hz3cbUKkA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ----- > It's wrecked in general. It also jumps around for any REALTIME > adjustment. >=20 > > So a CLOCK_REALTIME time stamp at fork would at least be correct > > vs. suspend resume. >=20 > But still wrecked vs REALTIME jumps, as in, when DST flips the clock > back an hour, your timestamp is in the future. >=20 > Any which way around the whole thing is buggered. The only real fix is > not using REALTIME anything. Which is why I'm loath to add that REALTIME > timestamp at fork(), it just encourages more use. Thank you for feedback and listing all other problems. I'll adjust test expectations. Regards, Jan