From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [RFC] Initial alpha-0 for new page allocator API Date: Fri, 22 Sep 2006 22:02:41 +0200 References: <200609222110.25118.ak@suse.de> <1158955850.24572.37.camel@localhost.localdomain> In-Reply-To: <1158955850.24572.37.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200609222202.41692.ak@suse.de> Sender: owner-linux-mm@kvack.org Return-Path: To: Alan Cox Cc: Christoph Lameter , Martin Bligh , akpm@google.com, linux-kernel@vger.kernel.org, Christoph Hellwig , James Bottomley , linux-mm@kvack.org List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org