Re: [PATCH 1/7] async: Asynchronous function calls to speed upkernel boot

[Arjan van de Ven]

On Sun, 15 Feb 2009 11:16:36 -0800
Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:

> On Fri, 13 Feb 2009 23:29:26 -0800
> Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> 
> > On Fri, 13 Feb 2009 20:59:49 -0800 Arjan van de Ven
> > <arjan@xxxxxxxxxxxxx> wrote:
> > 
> > > On Fri, 13 Feb 2009 16:22:00 -0800
> > > Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> > > 
> > > > It means that sometimes, very rarely, the callback function will
> > > > be called within the caller's context.
> > > 
> > > for the cases that use it right now it is ok.
> > 
> > That doesn't mean it's any good!  There are only two callsites.
> 
> .. in mainline.
> There's a few more in various maintainer trees.
> 
> > 
> > Plus there's the issue which I mentioned: if someone _does_ call
> > this from atomic context they'll only find out about their bug when
> > the GFP_ATOMIC allocation fails.  This is bad!
> 
> as far as I know all current and pending callsites can deal with
> GFP_KERNEL, so I would just switch it to that for those; solves the
> entire issue. (I do need to check the suspend/resume speed
> improvements, S/R tends to be tricky with interrupts-off)
> 


btw if you have a poster child in the kernel that you would like to see
use the new stuff let me know; very often having one or two good use
cases makes the discussion and design a ton easier.


-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
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