Re: [PATCH 3/3] reuse __free_pages_exact() in __alloc_pages_exact()

[Michal Nazarewicz]

On Tue, 12 Apr 2011 17:24:24 +0200, Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>  
wrote:

> On Tue, 2011-04-12 at 12:29 +0200, Michal Nazarewicz wrote:
> > On Tue, 12 Apr 2011 00:03:48 +0200, Dave Hansen  
> > <dave@xxxxxxxxxxxxxxxxxx>
> > wrote:
> > > diff -puN mm/page_alloc.c~reuse-free-exact mm/page_alloc.c
> > > --- linux-2.6.git/mm/page_alloc.c~reuse-free-exact	2011-04-11
> > > 15:01:17.701822598 -0700
> > > +++ linux-2.6.git-dave/mm/page_alloc.c	2011-04-11 15:01:17.713822594
> > > -0700
> > > @@ -2338,14 +2338,11 @@ struct page *__alloc_pages_exact(gfp_t g
> > > 	page = alloc_pages(gfp_mask, order);
> > >  	if (page) {
> > > -		struct page *alloc_end = page + (1 << order);
> > > -		struct page *used = page + nr_pages;
> > > +		struct page *unused_start = page + nr_pages;
> > > +		int nr_unused = (1 << order) - nr_pages;
> >
> > How about unsigned long?
>
> Personally, I'd rather leave this up to the poor sucker that tries to
> set MAX_ORDER to 33.  If someone did that, we'd end up with kernels that
> couldn't even boot on systems with less than 16GB of RAM since the
> (required) flatmem mem_map[] would take up ~14.3GB.  They couldn't
> handle memory holes and couldn't be NUMA-aware, either.

I was thinking more about the fact that the int will get converted
anyway when calling __free_pages_exact() and it makes no sense for
number of pages to be negative.  Just a suggestion, no strong
feelings.

--
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michal "mina86" Nazarewicz    (o o)
ooo +-----<email/xmpp: mnazarewicz@xxxxxxxxxx>-----ooO--(_)--Ooo--
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