From: "Michal Nazarewicz" <mina86@mina86.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Timur Tabi <timur@freescale.com>,
Andi Kleen <andi@firstfloor.org>, Mel Gorman <mel@csn.ul.ie>,
Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>
Subject: Re: [PATCH 3/3] reuse __free_pages_exact() in __alloc_pages_exact()
Date: Tue, 12 Apr 2011 17:57:23 +0200 [thread overview]
Message-ID: <op.vtt09xt73l0zgt@mnazarewicz-glaptop> (raw)
In-Reply-To: <1302621864.8321.1856.camel@nimitz>
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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next prev parent reply other threads:[~2011-04-12 15:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-11 22:03 [PATCH 1/3] rename alloc_pages_exact() Dave Hansen
2011-04-11 22:03 ` [PATCH 2/3] make new alloc_pages_exact() Dave Hansen
2011-04-11 22:22 ` Andrew Morton
2011-04-11 22:36 ` Dave Hansen
2011-04-11 22:42 ` Timur Tabi
2011-04-12 10:28 ` Michal Nazarewicz
2011-04-12 15:04 ` Dave Hansen
2011-04-12 15:58 ` Michal Nazarewicz
2011-04-13 23:23 ` Dave Hansen
2011-04-11 22:03 ` [PATCH 3/3] reuse __free_pages_exact() in __alloc_pages_exact() Dave Hansen
2011-04-12 10:29 ` Michal Nazarewicz
2011-04-12 15:24 ` Dave Hansen
2011-04-12 15:57 ` Michal Nazarewicz [this message]
2011-04-12 17:07 ` [PATCH 1/3] rename alloc_pages_exact() Namhyung Kim
2011-04-12 17:11 ` Dave Hansen
2011-04-14 20:01 Dave Hansen
2011-04-14 20:01 ` [PATCH 3/3] reuse __free_pages_exact() in __alloc_pages_exact() Dave Hansen
2011-04-14 22:00 ` David Rientjes
2011-04-14 22:07 ` Dave Hansen
2011-04-14 22:09 ` David Rientjes
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