Re: [patch 2/2] x86, fpu: lazy allocation of FPU area - v3

[Arjan van de Ven]

H. Peter Anvin wrote:
> Pavel Machek wrote:
> > On Thu 2008-03-06 16:51:41, Ingo Molnar wrote:
> > > * Pavel Machek <pavel@xxxxxx> wrote:
> > >
> > > > > > kmem_cache_alloc() can fail (return NULL) and not handling it is a 
> > > > > > bug.
> > > > > oops. you are correct. Will send a sigsegv in the failure case 
> > > > > then. Thanks.
> > > > You are introducing possibility of hard to debug error, where 
> > > > previous code just worked... Does not look like good idea to me.
> > > hm, how does it differ from any other allocation failure? We could fail 
> >
> > Well, we should not be sending SIGSEGV...? SIGBUS would be cleaner, or
> > SIGKILL... what happens when userland tries to catch this one?
>
> I'm confused...
>
> Normally when we need memory for userspace and can't get it, we put the 
> process to sleep until memory is available.

that's what GFP_KERNEL does
> Why is this different in any way?

this is just for handling the case where that fails
(basically near/totally OOM or the case where you get a fatal signal)

maybe we need a GFP_KILLABLE now that we have a TASK_KILLABLE...

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