WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: Q: Clarification about extra option ..Re: [Xen-devel] Re: [PATCH] pv

To: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Subject: Re: Q: Clarification about extra option ..Re: [Xen-devel] Re: [PATCH] pvops: Make suspend work when CONFIG_SUSPEND=n
From: Shriram Rajagopalan <rshriram@xxxxxxxxx>
Date: Fri, 4 Mar 2011 11:49:28 -0800
Cc: Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>, Jeremy Fitzhardinge <Jeremy.Fitzhardinge@xxxxxxxxxx>, Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>, Frank Pan <frankpzh@xxxxxxxxx>, "Rafael J. Wysocki" <rjw@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Fri, 04 Mar 2011 11:51:03 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <20110304182602.GA4004@xxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <AANLkTikcbVEXdRsS1WYCNTinuYLcmiJ1dz2ReS18_A+3@xxxxxxxxxxxxxx> <1299238501.6552.295.camel@xxxxxxxxxxxxxxxxxxxxxx> <AANLkTikOb2n7bq=w9RMdN7_NqR5UTom=ed+GuS8QyL_w@xxxxxxxxxxxxxx> <1299239542.6552.302.camel@xxxxxxxxxxxxxxxxxxxxxx> <AANLkTi=iQs4J8p+ix2i0OcY_63EKUB968NeBHVxts6P+@xxxxxxxxxxxxxx> <20110304155610.GD8391@xxxxxxxxxxxx> <AANLkTimUAnJXaLdPQC1+LmVqNU2h9JDTCzRLFzVTfLUK@xxxxxxxxxxxxxx> <20110304182602.GA4004@xxxxxxxxxxxx>
Reply-to: rshriram@xxxxxxxxx
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
On Fri, Mar 4, 2011 at 10:26 AM, Konrad Rzeszutek Wilk
<konrad.wilk@xxxxxxxxxx> wrote:
> .. snip..
>> >>  Someone suggested creating a new user visible hibernate symbol that would
>> >> solve this issue and make the main hibernate logic depend on this symbol 
>> >> rather
>> >> than the HIBERNATE symbol. I could certainly spin up a patch for that but 
>> >> nobody
>> >> seemed to have reached a conclusion.
>> >
>> > Please do. I was under the understanding that we were waiting for a 
>> > victi^H^H^Hvolunteer
>> > to implement that.
>> >
>> > That was the only thing gatting your patchset going in.
>> >
>> >
>>
>> I certainly would have long time ago but for this comment in the thread
>> "xen: fix XEN_SAVE_RESTORE Kconfig dependencies"
>>
>> Rafael:
>>  I think we can introduce CONFIG_HIBERNATE_INTERFACE that will be 
>> user-visible
>> option instead of CONFIG_HIBERNATION and will select the latter.  Then,
>> CONFIG_XEN_SAVE_RESTORE will also be able to select CONFIG_HIBERNATION 
>> without
>> building the hibernate interface in, which will prevent user space from being
>> confused, but that will cause too much code to be built anyway.
>>
>> If by "too much code to be built", he meant the increase in kernel
>> image size, then its not much of a deal :P.
>> But if he meant, "too much code rework", then it is an issue.
>
> The idea here is that the /sys/power/state won't be exposed with the "disk"
> option.
>
>>
>> But IMO, the CONFIG_HIBERNATE_INTERFACE needs to go in,
>> only in the main hibernation initiator logic, as we still need the
>> CONFIG_HIBERNATE
>> pieces of every driver anyway (their freeze/thaw routines).
>
> Right. The idea here is to seperate the sysfs interface to be behind
> another config option. So you can still enable the hibernate kernel code
> but without exposing it to the userland.
>
> Rafael,
>
> That is the general idea, right?
>
>

I was thinking along the lines of
config HIBERNATION
 def_bool n

config HIBERNATION_INTERFACE
 select HIBERNATE

config XEN_SAVE_RESTORE
 select HIBERNATION

in kernel/power/Makefile
obj-$(CONFIG_HIBERNATION_INTERFACE)  += hibernate.o snapshot.o swap.o \

  user.o block_io.o

Will this be sufficient to prevent unnecessary code from being built?
Or, is this oversimplified file exclusion totally wrong and I have to
dig deeper?

>From a cursory glance, these files seem to be dealing solely with SWSUSP which
roughly does the following:
 1. freezing devices (using pm_op functions in main.c)
 2. saving memory to swap
 3. thawing on resume (using pm_op functions in main.c)

XEN_SAVE_RESTORE only needs steps 1 & 3.


shriram

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

<Prev in Thread] Current Thread [Next in Thread>