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

[Shriram Rajagopalan <rshriram@cs.ubc.ca>]

On Tue, Feb 22, 2011 at 12:43 PM, Konrad Rzeszutek Wilk
<konrad.wilk@oracle.com> 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@cs.ubc.ca>
>> ---
>>  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
>        default y
>
>  config XEN_DEBUG_FS
>
>
On that aspect, just noticed
config PM_SLEEP
        bool
        depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE
        default y
we could get rid of XEN_SAVE_RESTORE as the suspend/resume code doesnt
depend on PM_SLEEP
anymore.