From: Ian Campbell <ijc@hellion.org.uk> To: Alan Stern <stern@rowland.harvard.edu> Cc: Brendan Cully <brendan@cs.ubc.ca>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, LKML <linux-kernel@vger.kernel.org>, "Rafael J. Wysocki" <rjw@sisk.pl>, "linux-pm@lists.linux-foundation.org" <linux-pm@lists.linux-foundation.org>, "SUZUKI, Kazuhiro" <kaz@jp.fujitsu.com> Subject: Re: [Xen-devel] Re: [linux-pm] [PATCH 0/2] Fix hangup after creating checkpoint on Xen. Date: Thu, 10 Feb 2011 11:40:05 +0000 [thread overview] Message-ID: <1297338005.20491.163.camel@zakaz.uk.xensource.com> (raw) In-Reply-To: <Pine.LNX.4.44L0.1102091837050.18843-100000@netrider.rowland.org> On Wed, 2011-02-09 at 23:42 +0000, Alan Stern wrote: > In fact there already is a "fast suspend & resume" path in the PM core. > It's the freeze/thaw procedure used when starting to hibernate. The > documentation specifically says that drivers' freeze methods are > supposed to quiesce their devices but not change power levels. In > addition, the thaw method is invoked as part of recovery from a failed > hibernation attempt, so it already has the "cancel" semantics that xen > seems to want. Sounds like that would work and I would much prefer to simply make correct use of the core functionality. So PMSG_FREEZE is balanced by either PMSG_RECOVER or PMSG_THAW depending on whether the suspend was cancelled or not? So the sequence of events is something like: dpm_suspend_start(PMSG_FREEZE); dpm_suspend_noirq(PMSG_FREEZE); sysdev_suspend(PMSG_QUIESCE); cancelled = suspend_hypercall() sysdev_resume(); dpm_resume_noirq(cancelled ? PMSG_RECOVER : PMSG_THAW); dpm_resume_end(cancelled ? PMSG_RECOVER : PMSG_THAW); ? (For comparison we currently have: > > > dpm_suspend_start(PMSG_SUSPEND); > > > > > > dpm_suspend_noirq(PMSG_SUSPEND); > > > > > > sysdev_suspend(PMSG_SUSPEND); > > > /* suspend hypercall */ > > > sysdev_resume(); > > > > > > dpm_resume_noirq(PMSG_RESUME); > > > > > > dpm_resume_end(PMSG_RESUME); ) Ian. -- Ian Campbell Current Noise: Neil Young - Angry World If only one could get that wonderful feeling of accomplishment without having to accomplish anything.
WARNING: multiple messages have this Message-ID (diff)
From: Ian Campbell <ijc@hellion.org.uk> To: Alan Stern <stern@rowland.harvard.edu> Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, LKML <linux-kernel@vger.kernel.org>, "Rafael J. Wysocki" <rjw@sisk.pl>, Brendan Cully <brendan@cs.ubc.ca>, "linux-pm@lists.linux-foundation.org" <linux-pm@lists.linux-foundation.org>, "SUZUKI, Kazuhiro" <kaz@jp.fujitsu.com> Subject: Re: Re: [linux-pm] [PATCH 0/2] Fix hangup after creating checkpoint on Xen. Date: Thu, 10 Feb 2011 11:40:05 +0000 [thread overview] Message-ID: <1297338005.20491.163.camel@zakaz.uk.xensource.com> (raw) In-Reply-To: <Pine.LNX.4.44L0.1102091837050.18843-100000@netrider.rowland.org> On Wed, 2011-02-09 at 23:42 +0000, Alan Stern wrote: > In fact there already is a "fast suspend & resume" path in the PM core. > It's the freeze/thaw procedure used when starting to hibernate. The > documentation specifically says that drivers' freeze methods are > supposed to quiesce their devices but not change power levels. In > addition, the thaw method is invoked as part of recovery from a failed > hibernation attempt, so it already has the "cancel" semantics that xen > seems to want. Sounds like that would work and I would much prefer to simply make correct use of the core functionality. So PMSG_FREEZE is balanced by either PMSG_RECOVER or PMSG_THAW depending on whether the suspend was cancelled or not? So the sequence of events is something like: dpm_suspend_start(PMSG_FREEZE); dpm_suspend_noirq(PMSG_FREEZE); sysdev_suspend(PMSG_QUIESCE); cancelled = suspend_hypercall() sysdev_resume(); dpm_resume_noirq(cancelled ? PMSG_RECOVER : PMSG_THAW); dpm_resume_end(cancelled ? PMSG_RECOVER : PMSG_THAW); ? (For comparison we currently have: > > > dpm_suspend_start(PMSG_SUSPEND); > > > > > > dpm_suspend_noirq(PMSG_SUSPEND); > > > > > > sysdev_suspend(PMSG_SUSPEND); > > > /* suspend hypercall */ > > > sysdev_resume(); > > > > > > dpm_resume_noirq(PMSG_RESUME); > > > > > > dpm_resume_end(PMSG_RESUME); ) Ian. -- Ian Campbell Current Noise: Neil Young - Angry World If only one could get that wonderful feeling of accomplishment without having to accomplish anything.
next prev parent reply other threads:[~2011-02-10 11:40 UTC|newest] Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-02-07 9:07 [PATCH 0/2] Fix hangup after creating checkpoint on Xen SUZUKI, Kazuhiro 2011-02-07 9:08 ` [PATCH 1/2] " SUZUKI, Kazuhiro 2011-02-07 9:08 ` SUZUKI, Kazuhiro 2011-02-07 9:08 ` [PATCH 2/2] " SUZUKI, Kazuhiro 2011-02-07 9:08 ` SUZUKI, Kazuhiro 2011-02-07 9:35 ` [PATCH 0/2] " Rafael J. Wysocki 2011-02-08 11:22 ` Ian Campbell 2011-02-08 11:22 ` Ian Campbell 2011-02-08 16:46 ` Alan Stern 2011-02-08 16:46 ` [linux-pm] " Alan Stern 2011-02-08 16:46 ` Alan Stern 2011-02-08 17:35 ` Ian Campbell 2011-02-08 17:35 ` Ian Campbell 2011-02-09 23:16 ` Brendan Cully 2011-02-09 23:16 ` Brendan Cully 2011-02-09 23:42 ` Alan Stern 2011-02-09 23:42 ` Alan Stern 2011-02-10 11:40 ` [Xen-devel] " Ian Campbell 2011-02-10 11:40 ` Ian Campbell [this message] 2011-02-10 11:40 ` Re: [linux-pm] " Ian Campbell 2011-02-10 16:00 ` [Xen-devel] " Alan Stern 2011-02-10 16:00 ` [Xen-devel] Re: [linux-pm] " Alan Stern 2011-02-10 16:00 ` Alan Stern 2011-02-10 16:26 ` [Xen-devel] " Rafael J. Wysocki 2011-02-10 16:26 ` Rafael J. Wysocki 2011-02-10 16:26 ` [Xen-devel] " Rafael J. Wysocki 2011-02-10 16:34 ` Ian Campbell 2011-02-10 16:34 ` [Xen-devel] Re: [linux-pm] " Ian Campbell 2011-02-10 16:34 ` Ian Campbell 2011-02-10 17:01 ` [Xen-devel] " Rafael J. Wysocki 2011-02-10 17:01 ` Rafael J. Wysocki 2011-02-17 7:56 ` [PATCH] update comments in pm.h describing Xen Guest save/restore/checkpoint use case Shriram Rajagopalan 2011-02-17 7:56 ` Shriram Rajagopalan 2011-02-17 10:56 ` [Xen-devel] " Ian Campbell 2011-02-17 10:56 ` Ian Campbell 2011-02-10 17:01 ` [Xen-devel] Re: [PATCH 0/2] Fix hangup after creating checkpoint on Xen Rafael J. Wysocki 2011-02-10 18:56 ` [Xen-devel] Re: [linux-pm] " Alan Stern 2011-02-10 18:56 ` Alan Stern 2011-02-10 18:56 ` [Xen-devel] " Alan Stern 2011-02-09 23:42 ` Alan Stern 2011-02-10 11:31 ` [Xen-devel] Re: [linux-pm] " Ian Campbell 2011-02-10 11:31 ` Ian Campbell 2011-02-10 12:40 ` Ian Campbell 2011-02-10 19:31 ` Brendan Cully 2011-02-11 9:14 ` Ian Campbell 2011-02-11 9:37 ` Pasi Kärkkäinen 2011-02-11 9:51 ` Ian Campbell 2011-02-11 18:13 ` Shriram Rajagopalan 2011-02-14 9:15 ` Ian Campbell 2011-02-14 9:27 ` Ian Campbell 2011-02-10 17:53 ` [Xen-devel] " Brendan Cully 2011-02-10 17:53 ` [Xen-devel] Re: [linux-pm] " Brendan Cully 2011-02-10 17:53 ` Brendan Cully 2011-02-10 11:31 ` [Xen-devel] " Ian Campbell 2011-02-09 23:16 ` Brendan Cully 2011-02-08 17:35 ` Ian Campbell 2011-02-08 11:22 ` Ian Campbell 2011-02-07 9:35 ` Rafael J. Wysocki
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