From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753648AbbGQXAh (ORCPT ); Fri, 17 Jul 2015 19:00:37 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:43959 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752392AbbGQXAf convert rfc822-to-8bit (ORCPT ); Fri, 17 Jul 2015 19:00:35 -0400 From: "Rafael J. Wysocki" To: Pali =?ISO-8859-1?Q?Roh=E1r?= Cc: Alasdair Kergon , Mike Snitzer , Neil Brown , Len Brown , Pavel Machek , dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Subject: Re: [PATCH v2 1/3] PM suspend/hibernate: Call notifier after freezing processes Date: Sat, 18 Jul 2015 01:27:15 +0200 Message-ID: <3179448.TScsKEAuyR@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/4.1.0-rc5+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <20150716073302.GA10393@pali> References: <1428254419-7334-1-git-send-email-pali.rohar@gmail.com> <3729395.1oJCgMXcLU@vostro.rjw.lan> <20150716073302.GA10393@pali> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday, July 16, 2015 09:33:02 AM Pali Rohár wrote: > On Thursday 16 July 2015 03:02:03 Rafael J. Wysocki wrote: > > On Sunday, June 21, 2015 01:20:32 PM Pali Rohár wrote: > > > To prevent race conditions on userspace processes with I/O some taks must be > > > called after processes are freezed. This patch adds new events which are > > > delivered by pm_notifier_call_chain() after freezing processes when doing > > > suspend or hibernate action. > > > > > > Signed-off-by: Pali Rohár > > > --- > > > include/linux/suspend.h | 2 ++ > > > kernel/power/hibernate.c | 2 ++ > > > kernel/power/suspend.c | 4 +++- > > > 3 files changed, 7 insertions(+), 1 deletion(-) > > > > > > diff --git a/include/linux/suspend.h b/include/linux/suspend.h > > > index 5efe743..bc743c8 100644 > > > --- a/include/linux/suspend.h > > > +++ b/include/linux/suspend.h > > > @@ -368,6 +368,8 @@ static inline bool hibernation_available(void) { return false; } > > > #define PM_POST_SUSPEND 0x0004 /* Suspend finished */ > > > #define PM_RESTORE_PREPARE 0x0005 /* Going to restore a saved image */ > > > #define PM_POST_RESTORE 0x0006 /* Restore failed */ > > > +#define PM_HIBERNATION_AFTER_FREEZE 0x0007 /* After hibernation freeze */ > > > +#define PM_SUSPEND_AFTER_FREEZE 0x0008 /* After suspend freeze */ > > > > > > extern struct mutex pm_mutex; > > > > > > diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c > > > index 2329daa..184f7ee 100644 > > > --- a/kernel/power/hibernate.c > > > +++ b/kernel/power/hibernate.c > > > @@ -671,6 +671,8 @@ int hibernate(void) > > > if (error) > > > goto Exit; > > > > > > + pm_notifier_call_chain(PM_HIBERNATION_AFTER_FREEZE); > > > > Don't we need to check errors from these? > > > > If yes, what to do in this case? Fail hibernation and goto Exit? Yes, fail the transition in progress. > > Also, if you're adding AFTER_FREEZE, it would be good to add BEFORE_THAW too > > for symmetry. > > > > But there is no use case for BEFORE_THAW. At least it is not needed for now. For your use case, a single function pointer would be sufficient too. > > > + > > > lock_device_hotplug(); > > > /* Allocate memory management structures */ > > > error = create_basic_memory_bitmaps(); > > > diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c > > > index 8d7a1ef..ba2a945 100644 > > > --- a/kernel/power/suspend.c > > > +++ b/kernel/power/suspend.c > > > @@ -277,8 +277,10 @@ static int suspend_prepare(suspend_state_t state) > > > trace_suspend_resume(TPS("freeze_processes"), 0, true); > > > error = suspend_freeze_processes(); > > > trace_suspend_resume(TPS("freeze_processes"), 0, false); > > > - if (!error) > > > + if (!error) { > > > + pm_notifier_call_chain(PM_SUSPEND_AFTER_FREEZE); > > > return 0; > > > + } > > > > > > suspend_stats.failed_freeze++; > > > dpm_save_failed_step(SUSPEND_FREEZE); > > > > > > > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.