suspend2 merge (was Re: [Suspend2-devel] Re: CFS and suspend2: hang in atomic copy) [LWN.net]

From:		Pavel Machek <pavel-AT-ucw.cz>
To:		Ingo Molnar <mingo-AT-elte.hu>
Subject:		suspend2 merge (was Re: [Suspend2-devel] Re: CFS and suspend2: hang in atomic copy)
Date:		Tue, 24 Apr 2007 22:23:36 +0200
Cc:		Nigel Cunningham <nigel-AT-nigel.suspend2.net>, Christian Hesse <mail-AT-earthworm.de>, Nick Piggin <npiggin-AT-suse.de>, Mike Galbraith <efault-AT-gmx.de>, linux-kernel-AT-vger.kernel.org, Con Kolivas <kernel-AT-kolivas.org>, suspend2-devel-AT-lists.suspend2.net, Andrew Morton <akpm-AT-linux-foundation.org>, Linus Torvalds <torvalds-AT-linux-foundation.org>, Thomas Gleixner <tglx-AT-linutronix.de>, Arjan van de Ven <arjan-AT-infradead.org>

Hi!

> > From subsequent emails, I think you already got your answer, but just 
> > in case...
> > 
> > Yes, if you enabled "Replace swsusp by default" and you already had it 
> > set up for getting swsusp to resume. If not, and you're using an 
> > initrd/ramfs, you'll need to modify it to echo
> > > /sys/power/suspend2/do_resume after /sys and /proc are mounted but
> > prior to mounting / and so on.
> 
> yeah, went with the default suggested by your patch:
> 
>    CONFIG_SUSPEND2_REPLACE_SWSUSP=y
> 
> and it was pretty easy to set things up. I used "echo disk > 
> /sys/power/state" to trigger it.
> 
> In hindsight it was all pretty straightforward and suspend2 worked 
> beautifully on an UP and on an SMP system i tried. So in exchange for 
> suspend2 folks debugging a bug in CFS here's some suspend2 review 
> feedback ;) Any plans about moving suspend2 to the upstream kernel? It 
> should be pretty easy for it to co-exist with the current swsuspend 
> code.

Well, current uswsusp code can do most of stuff suspend2 can do, with
20% (or so) of kernel code. 

"Major feature" that is missing is ability to save 100% of memory if
it is all the pagecache. I think that is not that important; we have
200 line patch to do that, but noone was able to verify it is correct.

									Pavel
-- 
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