?? man malloc ??


On Mon, 03 Jan 2005 01:33:08 +0000, David Frascone wrote:

>
> I need to allocate 2mb for a brain dead driver. The existing driver likes to get it's memory by using mem=, then ioremaping the top of physical memory to get raw access to it.
>
> Basically, the area is for DMA / shared memory for a pci card.
>
> So, I'm trying to remove the mem= dependency, and just allocate a large buffer to use with the driver. But, kmalloc doesn't like to give out chunks that size.
>
> So, how do I malloc 2Mb of contiguous space?
>
> -Dave

I can only assume that this is a troll. Otherwise it would take a pretty big idiot to ignore the word "kernel" in the subject, and ignoring the sentence in the body where I said that kmalloc will not return me 2mb of memory.

Unless I'm the moron, and malloc was added to kernel space . . . let me know.

-Dave

On Sun, 02 Jan 2005 23:31:13 -0600
root wrote:

> ?? man malloc ??
>
>
> On Mon, 03 Jan 2005 01:33:08 +0000, David Frascone wrote:
>
> >
> > I need to allocate 2mb for a brain dead driver. The existing driver likes to get it's memory by using mem=, then ioremaping the top of physical memory to get raw access to it.
> >
> > Basically, the area is for DMA / shared memory for a pci card.
> >
> > So, I'm trying to remove the mem= dependency, and just allocate a large buffer to use with the driver. But, kmalloc doesn't like to give out chunks that size.
> >
> > So, how do I malloc 2Mb of contiguous space?
> >
> > -Dave
>


--
David Frascone

Psychiatrists stay on your mind.

David Frascone wrote:

>I need to allocate 2mb for a brain dead driver. The existing driver likes to get it's memory by using mem=, then ioremaping the top of physical memory to get raw access to it.
>
>Basically, the area is for DMA / shared memory for a pci card.
>
>So, I'm trying to remove the mem= dependency, and just allocate a large buffer to use with the driver. But, kmalloc doesn't like to give out chunks that size.
>
>So, how do I malloc 2Mb of contiguous space?
>
>-Dave
>
>
>
Hi Dave,

Perhaps __get_dma_pages ? Never used this function myself, but it's
described in http://www.xml.com/ldd/chapter/book/ch07.html
Anyway, linux.kernel might be a better newsgroup for you to ask.

Mihai

On Mon, 03 Jan 2005 15:58:17 +0100
Mihai Osian wrote:

> David Frascone wrote:
>
> >I need to allocate 2mb for a brain dead driver. The existing driver likes to get it's memory by using mem=, then ioremaping the top of physical memory to get raw access to it.
> >
> >Basically, the area is for DMA / shared memory for a pci card.
> >
> >So, I'm trying to remove the mem= dependency, and just allocate a large buffer to use with the driver. But, kmalloc doesn't like to give out chunks that size.
> >
> >So, how do I malloc 2Mb of contiguous space?
> >
> >-Dave
> >
> >
> >
> Hi Dave,
>
> Perhaps __get_dma_pages ? Never used this function myself, but it's
> described in http://www.xml.com/ldd/chapter/book/ch07.html
> Anyway, linux.kernel might be a better newsgroup for you to ask.
>

Thanks, that is exactly the direction I'm looking.

I still don't think that's going to be enough, though. Looks like it maxes out at 2mb, and I might need two 2mb chunks. I'll give it a try though. I'm leaning toward the bigphysmem patch now. It might give me what I need.

I'll post when I find a solution.

-Dave


--
David Frascone

Don't ask me, I'm making this up as I go!

On Mon, 03 Jan 2005 15:02:08 GMT
David Frascone wrote:

> On Mon, 03 Jan 2005 15:58:17 +0100
> Mihai Osian wrote:
>
> > David Frascone wrote:
> >
> > >I need to allocate 2mb for a brain dead driver. The existing driver likes to get it's memory by using mem=, then ioremaping the top of physical memory to get raw access to it.
> > >
> > >Basically, the area is for DMA / shared memory for a pci card.
> > >
> > >So, I'm trying to remove the mem= dependency, and just allocate a large buffer to use with the driver. But, kmalloc doesn't like to give out chunks that size.
> > >
> > >So, how do I malloc 2Mb of contiguous space?
> > >
> > >-Dave
> > >
> > >
> > >
> > Hi Dave,
> >
> > Perhaps __get_dma_pages ? Never used this function myself, but it's
> > described in http://www.xml.com/ldd/chapter/book/ch07.html
> > Anyway, linux.kernel might be a better newsgroup for you to ask.
> >
>
> Thanks, that is exactly the direction I'm looking.
>
> I still don't think that's going to be enough, though. Looks like it maxes out at 2mb, and I might need two 2mb chunks. I'll give it a try though. I'm leaning toward the bigphysmem patch now. It might give me what I need.
>
> I'll post when I find a solution.
>

Get DMA pages worked! It let me use an order of 9, for 512 4k pages (2mb). And, I was able to allocate both that I needed.

Thanks so much for your help!

-Dave

--
David Frascone

Computers are not intelligent. They only think they are.