Re: [PATCH] swsusp: Disable nonboot CPUs before entering platform suspend

From: Dave Jones
Date: Wed Mar 07 2007 - 19:21:16 EST


On Thu, Mar 08, 2007 at 12:13:05AM +0100, Rafael J. Wysocki wrote:

> > > Well, the WARN_ON() in arch/x86_64/kernel/acpi/sleep.c:init_low_mapping()
> > > triggers every time an SMP x86_64 box is suspended to disk using the platform
> > > mode (default), which is quite annoying IMHO and users think something wrong is
> > > going on. This will probably cause them to report the problem and I'd rather
> > > like to avoid handling these reports. ;-)
> >
> > Well sure - if patches were always error-free, we'd always apply them
> > immediately.
> >
> > The question is: is the risk of this patch breaking things exceeded by the
> > benefit which you describe?
>
> Well, it has survived some testing (http://lkml.org/lkml/2007/3/7/16). Also,
> before the code ordering in 2.6.21-rc* we had been running on one CPU
> here, so I think the risk is small.
>
> We could remove the WARN_ON() as Pavel has just suggested, but first I'd like
> to know who put it there and why.

It was introduced as part of ..

commit 55b2355eefc2f160246226d4d69fed431173a4d5
Author: Shaohua Li <shaohua.li@xxxxxxxxx>
Date: Fri Jun 23 02:04:49 2006 -0700

[PATCH] don't use flush_tlb_all in suspend time

flush_tlb_all uses on_each_cpu, which will disable/enable interrupt.
In suspend/resume time, this will make interrupt wrongly enabled.

Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxx>




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