Re: [Xen-devel] [PATCH 2/3] xen: use freeze/restore/thaw PM events for suspend/resume/chkpt

["Rafael J. Wysocki" <rjw@xxxxxxx>]

On Tuesday, February 22, 2011, Konrad Rzeszutek Wilk wrote:
> On Sat, Feb 19, 2011 at 03:12:37PM -0800, Shriram Rajagopalan wrote:
> > Use PM_FREEZE, PM_THAW and PM_RESTORE power events for
> > suspend/resume/checkpoint functionality, instead of PM_SUSPEND
> > and PM_RESUME. Use of these pm events fixes the Xen Guest hangup
> > when taking checkpoints. When a suspend event is cancelled
> > (while taking checkpoints once/continuously), we use PM_THAW
> > instead of PM_RESUME. PM_RESTORE is used when suspend is not
> > cancelled. See Documentation/power/devices.txt and linux/pm.h
> > for more info about freeze, thaw and restore. The sequence of
> > pm events in a suspend-resume scenario is shown below.
> > 
> >         dpm_suspend_start(PMSG_FREEZE);
> > 
> >                 dpm_suspend_noirq(PMSG_FREEZE);
> > 
> >                        sysdev_suspend(PMSG_FREEZE);
> >                        cancelled = suspend_hypercall()
> >                        sysdev_resume();
> > 
> >                dpm_resume_noirq(cancelled ? PMSG_THAW : PMSG_RESTORE);
> > 
> >        dpm_resume_end(cancelled ? PMSG_THAW : PMSG_RESTORE);
> > 
> > Signed-off-by: Shriram Rajagopalan <rshriram@xxxxxxxxx>
> > ---
> >  drivers/base/power/main.c                  |    8 ++++----
> >  drivers/xen/manage.c                       |   16 ++++++++--------
> >  drivers/xen/xenbus/xenbus_probe_frontend.c |    8 +++++---
> >  3 files changed, 17 insertions(+), 15 deletions(-)
> > 
> > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> > index 8340497..aab4f60 100644
> > --- a/drivers/base/power/main.c
> > +++ b/drivers/base/power/main.c
> > @@ -233,7 +233,7 @@ static int pm_op(struct device *dev,
> >             }
> >             break;
> >  #endif /* CONFIG_SUSPEND */
> > -#ifdef CONFIG_HIBERNATION
> > +#if defined(CONFIG_HIBERNATION) || defined(CONFIG_XEN_SAVE_RESTORE)
> 
> Could we just make CONFIG_XEN_SAVE_RESTORE depend on CONFIG_HIBERANTION?
> Like this:
> 
> 
> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> index 5b54892..838e20c 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -38,7 +38,7 @@ config XEN_MAX_DOMAIN_MEMORY
>  
>  config XEN_SAVE_RESTORE
>         bool
> -       depends on XEN && PM
> +       depends on XEN && PM && HIBERNATION

PM is not necessary.  Apart from this it looks OK.

It might be better to use select from the user's point of view, but I'm
not sure we can always assume that HIBERNATION will be selectable
by XEN_SAVE_RESTORE (eg. SWAP has to be set for HIBERNATION too).

>         default y
>  
>  config XEN_DEBUG_FS

Thanks,
Rafael

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel