On 25.01.2007 [19:35:15 -0800], Dave Hansen wrote:
> On Thu, 2007-01-25 at 15:24 -0600, Adam Litke wrote:
> > Hmm. On x86, sometimes gcc will optimize out the alloca() call. This
> > patch fixes it up nicely. Please apply.
> >
> > Signed-off-by: Adam Litke <[EMAIL PROTECTED]>
> >
> > diff --git a/tests/stack_grow_into_huge.c b/tests/stack_grow_into_huge.c
> > index fc8a030..7112428 100644
> > --- a/tests/stack_grow_into_huge.c
> > +++ b/tests/stack_grow_into_huge.c
> > @@ -49,6 +49,7 @@ void do_child()
> > {
> > while (1) {
> > alloca(16*1024*1024);
> > + sleep(0); /* Defeat the gcc optimizer */
> > }
> > }
>
> Aren't barriers the generally accepted (kernel-style) way of doing
> this?
>
> #define barrier() __asm__ __volatile__("": : :"memory")
Yes, but this isn't the kernel. Alternatively, we could probably just
not optimize this one testcase, if it's really gcc causing the problem.
> Can you do it in alloca() itself?
Well, for __GNUC__, we get:
# define alloca(size) __builtin_alloca (size)
And even for non-__GNUC__, the function is inlined.
So you want us to modify a GCC builtin, or a glibc, function for a
simple testcase?
No, thanks.
Thanks,
Nish
--
Nishanth Aravamudan <[EMAIL PROTECTED]>
IBM Linux Technology Center
-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys - and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Libhugetlbfs-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/libhugetlbfs-devel
