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* How to allocate hugepage in kernel module?
@ 2012-08-09  7:14 J.Hwan Kim
  2012-08-09  8:59 ` Denis Kirjanov
  0 siblings, 1 reply; 6+ messages in thread
From: J.Hwan Kim @ 2012-08-09  7:14 UTC (permalink / raw)
  To: kernelnewbies

Hi, everyone

How can I allocate physically contiguous huge page in kernel module ?
The routine of _get_fee_pages() fails whenever there are much free
memory in system.

I found the procedures for set hugepages with sysctl or
/proc/sys/vm/nr_hugepages
but I've not found the api for allocate the huge page in kernel.

Thanks in advnace.

Best Regards,
J.Hwan Kim

^ permalink raw reply	[flat|nested] 6+ messages in thread
* How to allocate hugepage in kernel module?
@ 2012-08-12  6:48 Murali Annamneni
  0 siblings, 0 replies; 6+ messages in thread
From: Murali Annamneni @ 2012-08-12  6:48 UTC (permalink / raw)
  To: kernelnewbies

Hi,
You can try by passing the flag GFP_KERNEL to __get_free_pages(). 
Eg: __get_free_pages(GFP_KERNEL,9)  where "9" represents -  Order of 9; means requesting for 2^9(=512) contiguous pages in virtual address space
         in order to allocate 2MB of contiguous memory.


Thanks & Regards
Murali 



-----Original Message-----
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Sent: Friday, August 10, 2012 9:30 PM
To: kernelnewbies at kernelnewbies.org
Subject: Kernelnewbies Digest, Vol 21, Issue 13

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Today's Topics:

   1. Re: How to allocate hugepage in kernel module? (J.Hwan Kim)
   2. Re: How to allocate hugepage in kernel module? (anish kumar)


----------------------------------------------------------------------

Message: 1
Date: Fri, 10 Aug 2012 09:00:12 +0900
From: "J.Hwan Kim" <frog1120@gmail.com>
Subject: Re: How to allocate hugepage in kernel module?
To: Denis Kirjanov <kirjanov@gmail.com>
Cc: kernelnewbies at kernelnewbies.org
Message-ID: <50244F0C.90109@gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

I set the __GFP_COMP flag to __get_free_pages(), but the result was same.

2012? 08? 09? 17:59, Denis Kirjanov ? ?:
> Forgot to CC kernelnewbies:
>
> Did you pass the __GFP_COMP flag to __get_free_pages?
>
>
> On 8/9/12, J.Hwan Kim<frog1120@gmail.com>  wrote:
>> Hi, everyone
>>
>> How can I allocate physically contiguous huge page in kernel module ?
>> The routine of _get_fee_pages() fails whenever there are much free 
>> memory in system.
>>
>> I found the procedures for set hugepages with sysctl or 
>> /proc/sys/vm/nr_hugepages but I've not found the api for allocate the 
>> huge page in kernel.
>>
>> Thanks in advnace.
>>
>> Best Regards,
>> J.Hwan Kim
>>
>>
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>




------------------------------

Message: 2
Date: Thu, 09 Aug 2012 20:18:02 -0700
From: anish kumar <anish198519851985@gmail.com>
Subject: Re: How to allocate hugepage in kernel module?
To: "J.Hwan Kim" <frog1120@gmail.com>
Cc: Denis Kirjanov <kirjanov@gmail.com>,
	kernelnewbies at kernelnewbies.org
Message-ID: <1344568682.1532.30.camel@anish-Inspiron-N5050>
Content-Type: text/plain; charset="UTF-8"

On Fri, 2012-08-10 at 09:00 +0900, J.Hwan Kim wrote:
> I set the __GFP_COMP flag to __get_free_pages(), but the result was 
> same.

Does this help?
sourd/core/memalloc.c +170

> 2012? 08? 09? 17:59, Denis Kirjanov ? ?:
> > Forgot to CC kernelnewbies:
> >
> > Did you pass the __GFP_COMP flag to __get_free_pages?
> >
> >
> > On 8/9/12, J.Hwan Kim<frog1120@gmail.com>  wrote:
> >> Hi, everyone
> >>
> >> How can I allocate physically contiguous huge page in kernel module ?
> >> The routine of _get_fee_pages() fails whenever there are much free 
> >> memory in system.
> >>
> >> I found the procedures for set hugepages with sysctl or 
> >> /proc/sys/vm/nr_hugepages but I've not found the api for allocate 
> >> the huge page in kernel.
> >>
> >> Thanks in advnace.
> >>
> >> Best Regards,
> >> J.Hwan Kim
> >>
> >>
> >>
> >> _______________________________________________
> >> Kernelnewbies mailing list
> >> Kernelnewbies at kernelnewbies.org
> >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >>
> >
> 
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies





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^ permalink raw reply	[flat|nested] 6+ messages in thread
* How to allocate hugepage in kernel module?
@ 2012-08-12  7:47 aurum spark
  0 siblings, 0 replies; 6+ messages in thread
From: aurum spark @ 2012-08-12  7:47 UTC (permalink / raw)
  To: kernelnewbies

Hi J.Hwan Kim,

Before we talk about APIs let's understand few things about requirement
1. How much contiguous memory do you require for you module ?
2. Should it be DMAble ?
3. Are you going to use that as shared memory with any other card or processor ?

So there are certain API which can provide you huge chunk of contiguous memory.
1. One of them as you are using is get_free_pages(). Try suggestions
by others to get rid of error.
2. Another thing you can use is dma_alloc_coherent(). But there is
limit on this and you should consider that other modules will also
required DMAble memory.
3. Depending on the kernel version you are using you can do
bootmem_reserve() API during initialization code of kernel and you can
keep this memory reserved for your module. Pass that as platform data.
4. You can try passing say mem=768M parameter through kernel
commandline(assuming you have 1G of memory). That will force kernel to
use 768M and you can use rest of the 256M memory by doing ioremap in
your module.

Regards,
~/Aurum

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2012-08-12  7:47 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-08-09  7:14 How to allocate hugepage in kernel module? J.Hwan Kim
2012-08-09  8:59 ` Denis Kirjanov
2012-08-10  0:00   ` J.Hwan Kim
2012-08-10  3:18     ` anish kumar
  -- strict thread matches above, loose matches on Subject: below --
2012-08-12  6:48 Murali Annamneni
2012-08-12  7:47 aurum spark

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