Re: [RFC] Initial alpha-0 for new page allocator API

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Friday 22 September 2006 22:10, Alan Cox wrote:
> Ar Gwe, 2006-09-22 am 21:10 +0200, ysgrifennodd Andi Kleen:
> > We already have that scheme. Any existing driver should be already converted
> > away from GFP_DMA towards dma_*/pci_*. dma_* knows all the magic
> > how to get memory for the various ranges. No need to mess up the 
> > main allocator.
> 
> Add an isa_device class and that'll fall into place nicely. isa_alloc_*
> will end up asking for 20bit DMA and it will work nicely.


The old school way is to pass NULL to pci_alloc_coherent()

> > that basically goes through the buddy lists freeing in >O(1) 
> > and does some directed reclaim, but that would likely be a separate
> > path anyways and not need your new structure to impact the O(1)
> > allocator.
> 
> Just search within the candidate 4MB (or whatever it is these days)
> chunks.
> 

What chunks?

> Ok the examples I know about are
> - ESS Maestro series audio - PCI, common on 32bit boxes a few years ago,
> no longer shipped and unlikely to be met on 64bit. Also slow allocations
> is fine.

And is fine with 16MB anyways I think.

> - Some aacraid, mostly only for control structures. Those found on 64bit
> are probably fine with slow alloc.

That is the only case where there are rumours they are not fine with 16MB.

> - Broadcom stuff - not sure if 30 or 31bit, around today and on 64bit

b44 is 30bit. That's true. I even got one here.

But it doesn't count really because we can handle it fine with existing 
16MB GFP_DMA

> - Floppy controller

That one only needs one page or so. In the worst case memory could be preallocated
in .bss for it. 

-Andi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux