Re: [PATCH, RFD]: Unbreak no-mmu mmap

[Greg Ungerer <gerg@snapgear.com>]

Bryan Wu wrote:
> On Wed, 2007-06-20 at 12:00 +0900, Paul Mundt wrote:
> > On Fri, Jun 08, 2007 at 03:53:49PM +0200, Bernd Schmidt wrote:
> > > diff --git a/mm/nommu.c b/mm/nommu.c
> > > index 2b16b00..7480a95 100644
> > > --- a/mm/nommu.c
> > > +++ b/mm/nommu.c
> > [snip]
> > > +	/*
> > > +	 * Must always set the VM_SPLIT_PAGES flag for single-page allocations,
> > > +	 * to avoid trying to get the order of the compound page later on.
> > > +	 */
> > > +	if (len == PAGE_SIZE)
> > > +		vma->vm_flags |= VM_SPLIT_PAGES;
> > > +	else if (flags & MAP_SPLIT_PAGES
> > And now you've just broken every non-blackfin nommu platform, as you've
> > only defined MAP_SPLIT_PAGES in asm-blackfin/mman.h.
> >
> > > +#ifdef CONFIG_NP2
> > > +	    || len < total_len
> > > +#endif
> > And what is this? It only shows up in the blackfin defconfig. This is not
> > the place to be putting board-specific hacks.
>
> Yes, it is our own NP2 memory allocator option. I think Bernd will fix
> it.

Theres no reason you can't add the MAP_SPLIT_PAGES define in
all the necessary places too.


> > On Tue, Jun 19, 2007 at 07:26:19PM -0400, Robin Getz wrote:
> > > I'm assuming that since no one had any large objections, that this is OK, and 
> > > we should send to Andrew to live in -mm for awhile?
> > No real objections to the approach, but it would be nice if these sorts
> > of things were test compiled for at least one platform that isn't yours,
> > so the obviously broken stuff is fixed before it's posted and someone
> > else has to find out about it later.
>
> Exactly, Could please do some simple test on your SH-NOMMU platform? And
> we are waiting for some feedback from other nommu arch maintainers.
>
> David and Grep could you please help on this? Maybe Robin got some m68k
> nommu by hand which can be used for testing, I only have Blackfin, -:))

I have compiled the patch on m68knommu (after adding a MAP_SPLIT_PAGES
define). And it seems to work ok with simple testing.

I don't have a problem with the change, though please do add that
MAP_SPLIT_PAGES define in the appropriate mman.h includes. And like Paul
said there is no place for CONFIG_NP2 in it currently. Please take
that out.

Regards
Greg




------------------------------------------------------------------------
Greg Ungerer  --  Chief Software Dude       EMAIL:     gerg@snapgear.com
Secure Computing Corporation                PHONE:       +61 7 3435 2888
825 Stanley St,                             FAX:         +61 7 3891 3630
Woolloongabba, QLD, 4102, Australia         WEB: http://www.SnapGear.com
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