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SubjectRe: [PATCH 3/3] reuse __free_pages_exact() in __alloc_pages_exact()
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On Tue, 12 Apr 2011 17:24:24 +0200, Dave Hansen <dave@linux.vnet.ibm.com>  
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@linux.vnet.ibm.com>
>> 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@google.com>-----ooO--(_)--Ooo--


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