kmalloc question

kmalloc question

[Andre.Messerschmidt]

Hi.

I always thought that it is save to use kmalloc in an interrupt handler as
long as you use GFP_ATOMIC. 
Now someone told me that it is not allowed to use these functions in any way
in an interrupt.

Can please someone clarify me here? 

regards
--
Andre Messerschmidt

Application Engineer
Infineon Technologies AG

Re: kmalloc question

[Alan Cox]

On Wed, 2002-06-05 at 06:25, Andre.Messerschmidt@infineon.com wrote:
> Hi.
> 
> I always thought that it is save to use kmalloc in an interrupt handler as
> long as you use GFP_ATOMIC. 
> Now someone told me that it is not allowed to use these functions in any way
> in an interrupt.
> 
> Can please someone clarify me here? 

GFP_ATOMIC is safe in an interrupt handler. You might get NULL back and
that it is your problem, but the kmalloc is safe

kmalloc question

[Finney, Steve]

Is kmalloc (GFP_KERNEL) on a 32 bit HIGHMEM enabled MIPS kernel (BCM/Sibyte processor) guaranteed to allocate memory from the low, KSEG0/1 addressible region? I'm having trouble sorting through the slab.c code. On this processor, only 256 MB of DRAM is directly addressible; with more than 256 MB of RAM, there is 256 MB in zone 0, and the remainder in zone 2. Zone 1 is empty.

Thanks,
sf

kmalloc question

[Finney, Steve]

Is kmalloc (GFP_KERNEL) on a 32 bit HIGHMEM enabled MIPS kernel (BCM/Sibyte processor) guaranteed to allocate memory from the low, KSEG0/1 addressible region? I'm having trouble sorting through the slab.c code. On this processor, only 256 MB of DRAM is directly addressible; with more than 256 MB of RAM, there is 256 MB in zone 0, and the remainder in zone 2. Zone 1 is empty.

Thanks,
sf

Re: kmalloc question

[Ralf Baechle]

On Wed, Oct 08, 2003 at 03:06:50PM -1000, Finney, Steve wrote:

> Is kmalloc (GFP_KERNEL) on a 32 bit HIGHMEM enabled MIPS kernel (BCM/Sibyte processor) guaranteed to allocate memory from the low, KSEG0/1 addressible region? I'm having trouble sorting through the slab.c code. On this processor, only 256 MB of DRAM is directly addressible; with more than 256 MB of RAM, there is 256 MB in zone 0, and the remainder in zone 2. Zone 1 is empty.

Yes.

  Ralf