[Click] Kernel BufferQueue

[Eddie Kohler]

Hi Beyers,

So Click actually supports a type of allocation that dynamically decides 
whether to use kmalloc() or vmalloc(), based on the size of the data to be 
allocated.  The allocation and freeing functions are

   void *ptr = CLICK_LALLOC(size_t size);
   CLICK_LFREE(void *ptr, size_t size);

Note that you have to specify the size when you delete the object as well as 
when you allocate it.

I've gone ahead and changed the Queue-derived elements to use LALLOC and LFREE 
instead of new[] and delete[].  That should mean that you can use regular 
Queues with huge capacities, no need for a special element.

Thanks,
Eddie


Beyers Cronje wrote:
> Hi Eddie, all,
> 
> I had a need to buffer incoming packets in Click kernel module for two 
> seconds on an interface with around 350+mbps traffic load with an 
> average packet count of 80,000pps. In other words I needed to buffer at 
> least 160,000 packets at any given time in the kernel module. Any 
> SimpleQueue derived queue's maximum capacity is 32761, limited by 
> kmalloc's maximum bucket size of 131048 bytes.  Click-install will crash 
> the kernel if you specify any larger capacity.
> 
> The attached element is a linuxmodule only element that uses vmalloc 
> instead of kmalloc to allocate queue memory. It installs and seems to 
> run fine on my system with a queue capacity of 500,000. It is derived 
> from NotifierQueue and overrides methods used in SimpleQueue to allocate 
> and free memory (initialize, live_reconfigure & cleanup).
> 
> Feel free to use or include in Click. Also feel free to rename as I 
> couldnt come up with a better name than BufferQueue :)
> 
> One drawback of calling vmalloc directly is that click/meminfo will not 
> reflect this allocation. Maybe a Click newvm(size_t) function can help 
> with this.
> 
> Cheers
> 
> Beyers Cronje