Re: [patch 0/9] Critical Mempools

[Sridhar Samudrala <sri@us.ibm.com>]

Benjamin LaHaise wrote:
> On Thu, Jan 26, 2006 at 03:32:14PM -0800, Matthew Dobson wrote:
>   
>>> I thought the earlier __GFP_CRITICAL was a good idea.
>>>       
>> Well, I certainly could have used that feedback a month ago! ;)  The
>> general response to that patchset was overwhelmingly negative.  Yours is
>> the first vote in favor of that approach, that I'm aware of.
>>     
>
> Personally, I'm more in favour of a proper reservation system.  mempools 
> are pretty inefficient.  Reservations have useful properties, too -- one 
> could reserve memory for a critical process to use, but allow the system 
> to use that memory for easy to reclaim caches or to help with memory 
> defragmentation (more free pages really helps the buddy allocator).
>
>   
>>> Gfp flag? Better memory reclaim functionality?
>>>       
>> Well, I've got patches that implement the GFP flag approach, but as I
>> mentioned above, that was poorly received.  Better memory reclaim is a
>> broad and general approach that I agree is useful, but will not necessarily
>> solve the same set of problems (though it would likely lessen the severity
>> somewhat).
>>     
>
> Which areas are the priorities for getting this functionality into?  
> Networking over particular sockets?  A GFP_ flag would plug into the current 
> network stack trivially, as sockets already have a field to store the memory 
> allocation flags.
>   
Yes, i have posted patches that use this exact approach last month that 
use a critical page pool with
GFP_CRITICAL flag.
      http://lkml.org/lkml/2005/12/14/65
      http://lkml.org/lkml/2005/12/14/66

Thanks
Sridhar