Re: __GFP flags and kmalloc failures

[Pierre Ossman <drzeus-list@drzeus.cx>]

Marcelo Tosatti wrote:

>On Tue, Nov 02, 2004 at 07:01:55PM +0100, Pierre Ossman wrote:
>  
>
>>Is there any other way of increasing the chances of actually getting the 
>>pages I need? Since it is DMA it needs to be one big block.
>>    
>>
>
>__GFP_NOFAIL, from gfp.h:
>
> * Action modifiers - doesn't change the zoning
> *
> * __GFP_REPEAT: Try hard to allocate the memory, but the allocation attempt
> * _might_ fail.  This depends upon the particular VM implementation.
> *
> * __GFP_NOFAIL: The VM implementation _must_ retry infinitely: the caller
> * cannot handle allocation failures.
> *
> * __GFP_NORETRY: The VM implementation must not retry indefinitely.
> */
>
>  
>
Yes, I've browsed through these. __GFP_NOFAIL seems like it can hang for 
a very long time (I don't know if there is an upper bound on how long it 
will have to wait for a free page). __GFP_REPEAT seems to work good 
enough in this case.
My question was meant to be more along the lines of "Is there anything I 
can do without resorting to unstable/interal API:s?".

Rgds
Pierre