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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,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 93E4AC04EB8 for ; Tue, 4 Dec 2018 19:29:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6042A20850 for ; Tue, 4 Dec 2018 19:29:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6042A20850 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ucw.cz 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 S1726217AbeLDT3b (ORCPT ); Tue, 4 Dec 2018 14:29:31 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:45798 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725841AbeLDT3a (ORCPT ); Tue, 4 Dec 2018 14:29:30 -0500 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id AC2D18089F; Tue, 4 Dec 2018 20:29:23 +0100 (CET) Date: Tue, 4 Dec 2018 20:29:26 +0100 From: Pavel Machek To: Ingo Molnar Cc: Michal Hocko , Oleg Nesterov , Linus Torvalds , Linux List Kernel Mailing , "Rafael J. Wysocki" , Chanho Min , Thomas Gleixner , Peter Zijlstra Subject: Re: [PATCH] Revert "exec: make de_thread() freezable (was: Re: Linux 4.20-rc4) Message-ID: <20181204192926.GA28651@amd> References: <20181203074700.GA21240@gmail.com> <20181203083942.GF31738@dhcp22.suse.cz> <20181203123149.GB31795@redhat.com> <20181203123857.GS31738@dhcp22.suse.cz> <20181203131006.GA10054@amd> <20181203135351.GU31738@dhcp22.suse.cz> <20181203141459.GA14789@amd> <20181203141737.GY31738@dhcp22.suse.cz> <20181204090228.GC73770@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="qMm9M+Fa2AknHoGS" Content-Disposition: inline In-Reply-To: <20181204090228.GC73770@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --qMm9M+Fa2AknHoGS Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > * Michal Hocko wrote: >=20 > > > Do we actually have reports of this happening for people outside > > > Android? > >=20 > > Not that I am aware of. >=20 > I'd say outside of Android 99% of the use of hibernation is the fail-safe= =20 > that distributions offer on laptops with very low battery levels: the=20 > emergency hibernation when there's almost no power left anymore. Android does not use hibernation AFAICT. Just s2ram. > Do these hibernation failure messages typically make it to persistent=20 > logs before the system uses power? I'd say so. If you have enough energy left for hibernation, you also have enough energy left to write the logs and sync. > In practice if that is buggy the kernel won't hibernate and the laptop=20 > will run out of power and the user will conclude "ugh, I shouldn't have= =20 > left my laptop turned on" - without looking into the logs and reporting,= =20 > as they'll perceive it as a user failure not a system failure. >=20 > I certainly saw random Linux laptops fail to hibernate over the years and= =20 > didn't report it, so if the distribution doesn't do the reporting=20 > automatically then chances are we'll never see it. There are many reasons while hibernation can fail. Buggy drivers, tasks in D state... And there are some when hibernation can fail "by design". If you swap does not have enough space to store the data, for example. Hibernation was designed to be non-intrusive, and reliable as in "if it hibernates it will also resume ok", but not reliable as in "it will always hibernate". I see that is problematic for "hibernate on battery low". Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --qMm9M+Fa2AknHoGS Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlwG1ZYACgkQMOfwapXb+vJeRQCgsyAz8KRczaAiDegP3s4cu2Qr ffUAnR3HMlIQ34Orrj2Ym3BCTAz18/4j =SvLS -----END PGP SIGNATURE----- --qMm9M+Fa2AknHoGS--