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 7DABCCA9EAF for ; Mon, 21 Oct 2019 10:47:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E85412067B for ; Mon, 21 Oct 2019 10:47:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=freesources.org header.i=@freesources.org header.b="kVuaB5c8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727433AbfJUKrw (ORCPT ); Mon, 21 Oct 2019 06:47:52 -0400 Received: from mx3.freesources.org ([195.34.172.217]:44467 "EHLO mx3.freesources.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726767AbfJUKrw (ORCPT ); Mon, 21 Oct 2019 06:47:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=freesources.org; s=20160526; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:References:Cc:To:From:Subject; bh=smwaZxFAXIzjE+Z5eyv3gt9YML7zW8Go/knn59KXMio=; b=kVuaB5c884fgJscRyGJwrS97j7avwSmDPDQ710P/UeL7q5QLgbFfJlmp9+MqX+2j1IeHISITe9efrtYNGsJmRbu7e2NQhKRQscaPsVsLGpr6NigwgMt30xyz/s/wrQfdAX4UOdDXosBRbG50Is1PSamxYD7n8nWfhp9bC0SrNJ8=; Received: from anon-45-115.vpn.ipredator.se ([46.246.45.115]) by mx3.freesources.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84_2) (envelope-from ) id 1iMVE1-0002x4-P1; Mon, 21 Oct 2019 10:47:45 +0000 Subject: Re: [RFC PATCH] PM: Add a switch for disabling/enabling sync() before suspend From: Jonas Meurer To: "Rafael J. Wysocki" Cc: linux-pm@vger.kernel.org, Pavel Machek , Len Brown , Tim Dittler References: <56b2db6a-2f76-a6d3-662a-819cfb18d424@freesources.org> <2847488.TR0R5COpHM@kreacher> <063b2b9e-19f1-e67a-1d54-b1a813364bb8@freesources.org> Openpgp: preference=signencrypt Autocrypt: addr=jonas@freesources.org; prefer-encrypt=mutual; keydata= mQINBEqFXAEBEAC+7gfLht8lDqGH1EPYoctDHvWQ4nk60UFDLfjqHmBGReL/9C7CyxYaqgY4 V1/DXPCmsO5PvHMSi6VPn3B81alPKMT6syQhxDN6CXETh/mrxRbTPyQVSKYdD/BvA94vgwfy iInR0N7K6J/mRxqKug14vXlABvfmyWBnW89d15OWs9qy1Ge1mHaA8UgIoUInR2mMqNHQf0nF /TtClN2uPmtv/GeGHfSSCQEjYq9Ih2Z1Re2hnwW1peEc0x7piKUXCXHGyrQdz5IE69SqV1gg vafUrWHNPWz5ZtXsihYioNi3ISuoHUjkKdn+t55en5tvWvi+2JQnMCGa/Wr7iA2EOxallR+z rQRBDe/6wp1XEz6vN1LqCeaRyVOR6q00PtN/Ot0tzPswrHKE6binqG6FBRbu+zeo87cNbMmH IAdIT3ysZCAwA2g310fBByCSiNnfhHg2GyqfC4eDtL/K7uVNqQQEon0yv8lzyUloofKER8eA W4PtahGcLLbREnekAwQMpU8y1a++QXdk1ckLoyGuBVpBX8PiRirzYVmYsGRMK2u0yIy73YYM gYpt6h+Vaoj5EyPbYuJRm3RItByzE84YBbKfA81Xn8FZWc2qTyTeKRMioTu37E/z46wSHCt9 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linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi Rafael and linux-pm maintainers, sorry for the noise, but again: is there a chance to get a brief review of my patchset? Probably it was a bad idea to rename the build-time flag, right? Should I revert that part of the patch? Cheers, jonas Jonas Meurer: > Hi Rafael and linux-pm maintainers, > > thanks a lot for your feedback, it's much appreciated! > > Rafael J. Wysocki: >>> This patch adds a run-time switch at `/sys/power/suspend_sync`. >> >> I'd prefer "sync_on_suspend". > > Agreed and changed. > >>> The switch allows to enable or disable the final sync() from the suspend.= >>> c >>> Linux Kernel system suspend implementation. This is useful to avoid race >>> conditions if block devices have been suspended before. Be aware that you= >>> >>> have to take care of sync() yourself before suspending the system if you >>> disable it here. >>> >>> Since this is my first patch against the Linux kernel and I don't >>> consider it ready for inclusion yet, I decided to send it to pm-linux >>> and the PM subsystem maintainers only first. Would be very glad if you >>> could take a look and comment on it :) >>> >>> Some questions: >>> >>> * There already is a build-time config flag[2] for en- or disabling the >>> sync() in suspend.c. Is it acceptable to have both a build-time *and* >>> a *run-time* switch? Or would a run-time switch have to replace the >>> build-time switch? If so, a direct question to Rafael, as you added >>> the build-time flag: Would that be ok for you? >> >> If there is a run-time knob to disable the syncing, the only reason for >> the config option to be there will be to set the default value of that. > > Makes sense. I changed the meaning of the build-time flag accordingly. > >>> To give a bit more contect: In Debian, we're currently working[3] on >>> support to suspend unlocked dm-crypt devices before system suspend. >>> During that work, we realized that the final sync() from Linux Kernel >>> system suspend implementation can lead to a dead lock. >> >> That's also true for FUSE filesystems I think and please note that this isn't >> going to work with hibernation (in which case filesystems are synced >> regardless). > > In my opinion, hibernation doesn't matter much. Since the memory is > powered off on hibernation anyway, there's no reason to luksSuspend the > devices beforehands, don't you think so? > >> The changes look reasonable to me. > > Glad to read. I'll send a second version of the patches as replies soon > after this mail. How do we go on from here? Could you imagine to review > them again and sign them afterwards? Or am I supposed to send them to > the lkml and wait for feedback before getting more signers? As written, > I'm new to the Linux Kernel development process and not sure what's the > logical next step to get the patches merged. > > Thanks again for your help! > > Cheers > jonas > >